Lithium Niobate Electro-Optic Modulators, Fiber-Coupled

10 GHz, 20 GHz, or 40 GHz Lithium Niobate (LiNbO₃) Modulators
Fiber-Coupled, High-Speed Modulation
Intensity, Phase, or IQ
X-Cut or Z-Cut Devices

LN27S-FC

40 GHz Phase Modulator with Polarizer, Z-Cut

LN81S-FC

10 GHz Intensity Modulator, X-Cut

LNLVL-IM-Z

Low V_π 40 GHz Intensity Modulator, Z-Cut

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Overview
Specs
Pin Diagrams
Lab Facts
Feedback

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Z-Cut LiNbO₃ Intensity Modulator Cross-Section

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X-Cut LiNbO₃ Intensity Modulator Cross-Section

Features

Titanium-Indiffused Waveguides
Low Optical Loss
Long-Term Bias Stability
Hermetically Sealed Packaging
Field-Replaceable RF Input Connectors
FC/PC Fiber Connectors

Thorlabs Quantum Electronics manufactures a variety of lithium niobate (LiNbO₃) optical phase and intensity modulators. These high-performance devices are based on titanium-indiffused waveguide technology, offer large bandwidths, and are ideal for developing high-speed modulation systems.

The modulators are fabricated from either X-cut or Z-cut LiNbO₃ (see the example diagrams to the right). X-cut intensity modulators employ a symmetrical design that provides low frequency-chirp in the modulated signal, while Z-cut intensity modulators provide more efficient modulation (i.e., lower V_π or half-wave voltage) at the expense of higher frequency-chirp. Phase modulators are only offered as Z-cut devices because their single optical path does not benefit from the symmetry of the X-cut design. The IQ modulator fully exploits the advantages of symmetry as an X-cut device.

The Z-cut devices are also capable of supporting both the ordinary and extraordinary optical modes, which have different modulation efficiencies. An integrated optical polarizer, positioned before the output port of the device, is included in Z-cut devices as only one mode is desirable for most applications. For applications where the polarizer is not desired, there is an option to have it removed. Please contact Tech Support with inquiries.

The modulators come with a polarization-maintaining (PM) input fiber pigtail and a single-mode (SM) output fiber pigtail that are terminated with FC/PC connectors. The PM fiber is keyed to the slow axis, which is also aligned to the extraordinary mode of the modulator. Please note that options for PM output fiber pigtails and FC/APC connectors are available for all LiNbO₃ modulators. For more information on custom configurations (e.g., fiber type, connectors) and quotes, please contact Tech Support.

All Thorlabs fiber-coupled lithium niobate modulators are compatible with our EO modulator drivers. Our fiber-coupled tunable lasers provide an ideal C-band or L-band source for use with these modulators. For all-in-one solutions in high-speed fiber optic test and measurement, we offer reference transmitters, optical transmitter with phase modulators, and calibrated electrical-to-optical converters.

Maximum Ratings for LiNbO₃ Modulators
Input Optical Power	100 mW
Input RF Power	24 dBm
Operating Temperature Range	0 °C - 70 °C
Storage Temperature Range	-40 °C - 85 °C

Intensity Modulator Specifications

Item #	LN81S-FC	LN82S-FC	LN05S-FC	LNLVL-IM-Z
Optical
Operating Wavelength^a	1525 nm - 1605 nm
Optical Insertion Loss	≤5.0 dB (4.0 dB Typ.)		≤5.5 dB (4.5 dB Typ.)
Optical Return Loss	≥40 dB
Optical Extinction Ratio (@ DC)	≥20 dB
Optical Input Power	≤100 mW
Electrical
E/O Bandwidth (-3 dB)	≥10 GHz (14 GHz Typ.)	≥10 GHz (14 GHz Typ.)	≥30 GHz (35 GHz Typ.)	10 GHz (Typ.)
Operating Frequency Range	DC to 15 GHz (Min)	DC to 15 GHz (Min)	DC to 40 GHz (Min)	DC to 40 GHz (Min)
RF V_π(@ 1 GHz)	≤6.5 V (5.6 V Typ.)	≤6.5 V (5.2 V Typ.)	≤6.0 V (5.5 V Typ.)	2.2 V (Typ.)
RF V_π(@ 20 GHz)	-	-	-	≤3.9 V (3.5 V Typ.)
RF V_π(@ 40 GHz)	-	-	-	≤6.0 V (5.0 V Typ.)
DC Bias V_π(@ 1 kHz)	≤10.0 V (6.5 V Typ.)	≤3.0 V (2.7 V Typ.)^b	≤5.0 V (3.5 V Typ.)	≤11.0 V (9.0 V Typ.)
S11	-12 dB (-10 dB Max), DC to 10 GHz		-12 dB (-10 dB Max), DC to 30 GHz -10 dB (-8 dB Max), 30 to 40 GHz	-12 dB (-10 dB Max), DC to 25 GHz -8 dB (-6 dB Max), 25 to 40 GHz
RF Input Power	24 dBm Maximum
Photodetector
Reverse Bias Voltage	-5.5 V to -3.0 V		N/A	N/A
Responsivity	0.1 mA/mW to 0.5 mA/mW		N/A	N/A
Output Optical Power Monitoring Range	-5 dBm to 10 dBm		N/A	N/A
Mechanical
Crystal Orientation	X-Cut	Z-Cut	Z-Cut	Z-Cut
RF Connection	Male SMP (GPO^®† Compatible), Full Detent		Female 1.85 mm (V)	Female 2.92 mm (K)
Fiber Type	Input: PANDA Polarization Maintaining Output: SMF-28^®‡ Single Mode
Fiber Lead Length	1.5 m Typ.
Environmental
Operating Case Temperature	0 °C - 70 °C
Storage Temperature	-40 °C - 85 °C

These modulators are designed for use at the specified wavelengths. Using the modulator at other wavelengths may cause an increase in the optical loss that is not covered under warranty. In some cases, this loss can be temporary; for instance, the increase in loss caused by shorter wavelengths can usually be reversed by heating the modulator to 80 °C for an hour.
The LN82S-FC includes a bias circuit that couples the DC bias onto the RF drive electrode. Depending on the application, an external DC block may be needed at the RF input.

Phase Modulator Specifications

Item #	LN53S-FC	LN27S-FC
Optical
Operating Wavelength^a	1525 nm - 1605 nm
Optical Insertion Loss	≤4.5 dB (3.0 dB Typ.)	≤4.5 dB (4.0 dB Typ.)
Optical Return Loss	≥40 dB
Optical Input Power	≤100 mW
Electrical
S11	-12 dB Typ. (-10 dB Max), DC to 10 GHz	-12 dB (-10 dB Max), DC to 30 GHz -10 dB (-8 dB Max), 30 to 40 GHz
E/O Bandwidth (-3 dB)	10 GHz Typ.	35 GHz Typ.
Operating Frequency Range	DC to 15 GHz (Typ.)	DC to 40 GHz (Typ.)
RF V_π	≤8.0 V (7.0 V Typ.) @ 10 GHz	≤9.5 V (7.5 V Typ.) @ 30 GHz
RF Input Power	24 dBm Maximum
Mechanical
Crystal Orientation	Z-Cut
RF Connection	Male SMP (GPO^® Compatible), Full Detent	Female 1.85 mm (V)
Fiber Type	Input: PANDA Polarization Maintaining Output: SMF-28^® Single Mode
Fiber Lead Length	1.5 m Typ.
Environmental
Operating Case Temperature	0 °C - 70 °C
Storage Temperature	-40 °C - 85 °C

These modulators are designed for use at the specified wavelengths. Using the modulator at other wavelengths may cause an increase in the optical loss that is not covered under warranty. In some cases, this loss can be temporary; for instance, the increase in loss caused by shorter wavelengths can usually be reversed by heating the modulator to 80 °C for an hour.

IQ Modulator Specifications

Item #	LN86S-FC
Optical
Operating Wavelength^a	1525 nm - 1575 nm
Optical Insertion Loss	≤6.0 dB (5.0 dB Typ.)
Optical Return Loss	≥40 dB
Optical Extinction Ratio (@ DC)	≥20 dB
Optical Input Power	≤100 mW
Electrical
S11	-12 dB (-10 dB Max), DC to 10 GHz
E/O Bandwidth (-3 dB)	≥14 GHz
Operating Frequency Range	DC to 18 GHz (Min)
RF V_π(@ 1 GHz)	≤6.0 V (4.5 V Typ.)
DC Bias V_π(@ 1 kHz), Modulator	≤5.5 V (4.5 V Typ.)^b
DC Bias V_π(@ 1 kHz), Phase Shifter	≤6.0 V
RF Input Power	24 dBm Maximum
Mechanical
Crystal Orientation	X-Cut
RF Connection	Male SMP (GPO^® Compatible), Full Detent
Fiber Type	Input: PANDA Polarization Maintaining Output: SMF-28^® Single Mode
Fiber Lead Length	1.5 m Typ.
Environmental
Operating Case Temperature	0 °C - 70 °C
Storage Temperature	-40 °C - 85 °C

These modulators are designed for use at the specified wavelengths. Using the modulator at other wavelengths may cause an increase in the optical loss that is not covered under warranty. In some cases, this loss can be temporary; for instance, the increase in loss caused by shorter wavelengths can usually be reversed by heating the modulator to 80 °C for an hour.
The LN86S-FC modulator includes bias circuits that couple the DC biases for the modulators onto the RF drive electrodes. Depending on the application, external DC blocks may be needed at the RF inputs.

† GPO is a registered trademark of Corning Optical Communications RF.
‡ SMF-28 is a registered trademark of Corning.

Intensity Modulator Pin Diagrams

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10 GHz Intensity Modulator Pin Diagram

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LN05S-FC 40 GHz Intensity Modulator Pin Diagram

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LNLVL-IM-Z Low V_π 40 GHz Intensity Modulator Pin Diagram

Phase Modulator Pin Diagrams

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10 GHz Phase Modulator Pin Diagram

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40 GHz Phase Modulator Pin Diagram

IQ Modulator Pin Diagrams

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20 Gb/s IQ Modulator Pin Diagram

Click for Full Lab Facts Summary

Driving an Electro-Optic Phase Modulator with the Amplified Output of a Function Generator

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Figure 1: Experimental Setup Used to Evaluate Whether a Basic RF Source Built Around a Function Generator Could be Sufficient to Drive a Fiber-Coupled EO Phase Modulator

Thorlabs offers a selection of fiber-coupled electro-optic (EO) modulators, which are ideal for modulating light from fiber-coupled laser sources. Applications frequently require EO modulators to be driven at rates of 1 GHz or higher, which places significant demands on the driving radio frequency (RF) voltage source. We investigated whether it would be possible to use a basic setup built around a function generator to drive a fiber-coupled EO phase modulator. The experimental setup we designed and implemented to test this possibility included instrumentation to record the spectrum of the modulated optical signal. By analyzing the modulated optical spectrum, we confirmed this basic RF source is a viable option for driving a fiber-coupled EO phase modulator. Our approach and results are documented in this Lab Fact.

Experimental Design and Setup

The design of the RF voltage source portion of the setup required first determining the power the RF source should supply to drive the fiber-coupled EO phase modulator. The power requirements were calculated after we made an estimate of the driving voltage needed to achieve the modulation depth desired for this application. Details describing our process for selecting a modulation depth, the relationship between modulation depth and driving voltage, and the calculations we used to estimate the power required from the RF voltage source are included in the Lab Facts document. From our investigations, we determined the power from the function generator alone would not be sufficient for our application. Our solution was to insert a low noise amplifier between the function generator and EO modulator. We also included an electrical low pass filter before the modulator to remove signal distortion that appeared to originate with the function generator. We drove the EO phase modulator with a sinusoidal RF voltage, which imparted a sinusoidal phase modulation on the 1550 nm CW laser signal.

A scanning Fabry-Perot interferometer, whose output was sent to an oscilloscope, was placed after the EO phase modulator and used to measure and monitor the spectrum of the modulated optical signal. It was necessary to use the Fabry-Perot interferometer for this purpose as it has the ability to resolve the very fine spectral features of the phase-modulated optical spectra: at a wavelength of 1550 nm, a frequency difference of 1 GHz is equivalent to a wavelength difference of 0.8 pm. The measured spectra were recorded as functions of scan time. In the Lab Facts document, we describe a straight-forward method to convert from units of Fabry-Perot scan time to units of relative optical frequency. For this work, we estimate Δf = (1.17 GHz/ms)Δt.

Experimental Results

As is described in the Lab Facts document, theory predicts the spectra of our phase modulated optical signals would include sets of symmetric sidebands arranged around the laser carrier peak at frequency f_o. The sidebands are displaced from the laser carrier peak frequency at integer multiples of the modulation frequency f_m (f_o ± Nf_m with N = 1, 2, ...). The relative heights of the sidebands are a function of the modulation depth, which is in turn a function of the peak-to-peak value of the RF driving voltage. Given the modulation depth, the relative amplitudes of the laser carrier peak and modulation sidebands can be calculated. This makes it possible to tailor the power distribution across the various peaks to meet an application's needs. We used the predictive power of this model to confirm our RF source was adequately driving the EO modulator.

The spectra shown in Figures 2 and 4 are representative of the modulation spectra we measured. The theoretical curves in Figure 3 are a function of modulation depth and plot the expected relative powers of the laser carrier peak (solid red curve), first order sidebands (dotted blue curve), second order sidebands (dotted green curve), and third order sidebands (dotted violet curve). The black arrow points to the modulation depth corresponding to the spectrum in Figure 2, and the gray arrow points to the modulation depth corresponding to the spectrum in Figure 4. From our results, we determined our measured and applied modulation frequencies agreed, and we confirmed the spectral power distributions in our optical spectra were consistent with the peak-to-peak driving voltage of the RF source. We conclude that the good agreement between the expected and recorded results validates the use of a basic RF source built around a function generator as a driver for fiber-coupled EO phase modulators.

EO Phase Modulator Spectrum for Vpp 3.63

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Figure 4: EO Phase Modulator Spectrum When V_pp = 3.63 V
The carrier frequency is f_o; the modulation frequency is f_m = 1 GHz. The X-axis reports the scanning time of the Fabry-Perot interferometer and can be directly related to the signal's relative frequency spectrum.

EO Phase Modulator Sideband Relative Power for 0.44 Modulation Depth

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Figure 3: Curves Relating the Power in the Carrier and Several Sideband Peaks as A Function of Modulatrion Depth
The 0.44 modulation depth indicated by the black arrow corresponds to Figure 2, and the 0.56 modulation depth indicated by the gray arrow corresponds to Figure 4.

EO Phase Modulator Spectrum for Vpp 2.85

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Figure 2: EO Phase Modulator Spectrum When V_pp = 2.85 V
The carrier frequency is f_o; the modulation frequency is f_m = 1 GHz. The X-axis reports the scanning time of the Fabry-Perot interferometer and can be directly related to the signal's relative frequency spectrum.

Posted Comments:

user (posted 2021-06-12 12:36:31.3)

I would like to reproduce the modulator EO bandwidth (S21) measurement for this modulator. My expectation is that I would sweep the RF input and monitor the output power on an optical power meter. If I have a single wavelength into a photodiode I obtain half the power at the DC term because of the square law nature of the detector. If I have multiple sidebands, these will beat to produce DC terms and IF terms in the photodiode. In heterodyne systems where I care about the RF I must ensure the photodiode amplifier has the appropriate bandwidth to pass those sidebands. My question is whether the IF beating terms created from the modulated sidebands are irrelevant to an optical power meter and if only the total DC power is used to determine the incident optical power. In other words, is the optical power meter only concerned with the DC power, or is it necessary to consider any IF generated? How does Thorlabs perform this measurement? Thank you.

YLohia (posted 2021-06-15 11:04:54.0)

We make the S21 measurement using a Vector Network Analyzer (VNA). For S21 in our test configuration, Port 1 of the VNA supplies a small-signal, frequency swept source that is coupled into the RF port of the modulator. A voltage is applied to the DC bias of the modulator in order to bias the modulator at quadrature (the half-power point). The optical output from the modulator is coupled into a high-speed photodetector; the bandwidth of the detector should meet or exceed the frequency range of the source. The output of the photodetector is coupled into Port 2 of the VNA, which measures the received signal. The response of the photodetector will need to be removed from the VNA measurement in order to get the response of the modulator (for Thorlabs’ ultrafast photoreceivers (https://www.thorlabs.com/navigation.cfm?guide_id=2558), a file with the response data for a specific device is available upon request).

Jim Zhang (posted 2021-05-24 12:21:30.1)

From specifications, it seems this product is for 1500 - 1600 nm wavelength application. My interest is at 1064 nm. Do you have similar product for 1064 nm wavelength applications?

YLohia (posted 2021-05-24 02:13:51.0)

Thank you for contacting Thorlabs. I have reached out to you directly regarding this.

mogendi Mogendi (posted 2021-05-06 19:58:31.46)

With show of diagrams, explain how intensity modulator functions, specifically LiNbO 3 modulator.

YLohia (posted 2021-05-07 10:45:35.0)

The lithium niobate intensity modulator is controlled by applying a voltage to the RF input. This directly changes the refractive index of the lithium niobate waveguide via the electro-optic effect. It is a Mach Zehnder Interferometer configuration, so the relative phase between the two arms of the MZI results in controllable constructive and destructive interference. This is how the intensity is changed. The input fiber is PM, so it is required to have the polarization aligned with the slow axis of the fiber to operate correctly. The source should be around 1550nm. The voltage required to switch between max signal level and minimum is called Vpi. Equivalently it is the voltage to cause a relative phase shift of pi radians in the MZI. The units are set to be biased around the middle of the negative slope. What this means is that, to reach about a maximum signal level, the user should apply –Vpi/2. To reach a minimum, the user should apply +Vpi/2. The bias point can also be separately adjusted with two of the pins on the package. The remaining two pins on the package are for photodiode feedback. The photodiode signal is low when the output into fiber is maximized. The photodiode signal is high when output into fiber is minimum. This is simply a direct connection to the photodiode, so it should be considered a current source. The current has to be detected by traversing some load resistance and measuring the voltage across the resistance. Typical current levels are uA to low mA range. More information, including diagrams and equations, can be found in online literature or in textbooks.

Markus Schmidt (posted 2021-05-01 18:44:45.22)

Hello, I read the datasheet of LN81S-FC. in page 2 you wrote "field replaceable smp connector" for it's RF connector. what do you mean about field replaceable ? Is that mean we can replace it with another RF connector?

YLohia (posted 2021-05-03 01:59:59.0)

Hello, thank you for contacting Thorlabs. The "field replaceable" connector is intended to be changed with another RF connector of the same type by the end-user in the event there is some damage to the existing connector.

Michael S (posted 2021-03-24 05:41:54.99)

Hello, The specs of the phase modulators state that the max input power is 24 dBm, consequently the maximum V_p2p should be 10 V. This in turn limits the achievable modulation depth, given that the typical V_pi is 7V. I am asking to verify that I have read and understood the specs correctly in order to respect the power limitations of the device. Thanks a lot.

YLohia (posted 2021-03-25 10:53:43.0)

Hello, thank you for contacting Thorlabs. Yes, your understanding here is correct -- the modulation depth will be limited by the 24 dBm max RF power (10.02 Vpp) and the Vpi spec of your device.

william B (posted 2021-03-18 15:46:45.29)

I am using a LN86S-FC. I observe much higher insertion losses (18db) when biased for max throughput. This test datasheet states a measured insertion loss of 5db. I have checked the input polarization and ensured it is aligned for maximum output power. What other things should I check? I am interested in buying more units, but I need to solve the excess loss issue first. Thanks in advance for your help.

YLohia (posted 2021-03-29 02:43:20.0)

Hello, thank you for contacting Thorlabs. Based on the description of the problem, it appears that there may be an issue with the fiber/connector. Please inspect the two fiber connectors under a fiberscope for damage and use a (low power) fiber fault tester to check for breaks along the length of the input and output fibers.

Preeti Yadav (posted 2021-02-09 05:25:29.177)

Hello! For our quantum key distribution setup, we want to inquire about the electro-optic phase modulator to achieve polarization control. Can the phase modulator be used to generate one of the four polarization states, say, linearly diagonal states at 45 degrees and -45 degrees, and circularly polarized states, left and right, upon inputting a linearly polarized light at 45 degrees to the modulator. At the moment we require the modulation frequency to be around 100 MHz, is that a possibility with the 10 GHz phase modulators? Thank you!

YLohia (posted 2021-03-15 03:34:56.0)

Hello, thank you for contacting Thorlabs. In theory, without the polarizer in the LN65S-FC (so the correct part number being LN53S-FC), you could use the modulator as a polarization controller. That being said, these modulators are not optimized for such applications and we wouldn't be able to spec performance. Additionally, there would be significant drift. Please also note that the output fiber is a regular single mode fiber, which is not designed to maintain any specific polarization state.

Van Rudd (posted 2020-12-29 19:38:47.09)

You have a nice plot showing how V_pi varies with frequency for the intensity modulators, but not the phase modulators. Do you have that data? Also, from what is listed on the spec page it looks like the intensity modulator has a lower V-pi than the phase modulator. Why is this? Thanks.

YLohia (posted 2021-01-15 02:08:45.0)

Unfortunately, we do not have plots of the EO Frequency Response for the Phase Modulators as this is not an easy measurement to make for Phase Modulators because an external interferometer is needed to characterize this data. The Vpi is different in the intensity and phase modulators because they have fundamentally different structures. The biggest difference is layout of the optical waveguides (the intensity modulator layout allows for a push-pull configuration, see the diagrams in the Overview section of this page). There are also other aspects of the device design that can affect the Vpi.

bo-Hun choi (posted 2020-07-22 01:30:45.28)

Hi I purchased a couple of your product "LN82S-FC" and am doing experiment. I want to use bias controller for LN82S because of the condition change as time. I wonder that the pin3 and 4 can be used for this purpose. Are these pins alive for this purpose? I am looking forward to hearing from you Adam

YLohia (posted 2020-07-22 09:37:20.0)

Hello Adam, thank you for contacting Thorlabs. Yes, Pins 3 & 4 are intended to be used for DC bias control. You may use our MBX bias controller for such an application.

user (posted 2020-06-09 12:14:14.403)

Does this device come with loose tube 900 micron or tight buffer 900 micron fiber?

YLohia (posted 2020-06-09 02:43:00.0)

Thank you for contacting Thorlabs. We use tight buffer fibers for these devices.

Zichao Zhou (posted 2020-03-04 22:58:45.923)

Hi I am a Ph.D student in University of Ottawa. I am planning to buy a single side band modulator. Here I have a few questions about this IQ modulator. I want to use this IQ modulator as a single side band modulator. I am wondering how should I give a RF frequency to this modulator. Should I give the the two frequency with exact 90 degree phase shift if I want to use it as a single side band modulator. How can I apply this frequency if I only have one radio frequency generator. Another question is that would the single side band modulator shift the original optical frequency to a lower frequency or a higher frequency. Can I control the direction of the frequency shifting. Looking forward to your reply. Thank you! Regards Zichao

asundararaj (posted 2020-03-06 10:08:07.0)

Thank you for contacting Thorlabs. I have reached out to you via email with this information.

Il-Bum Kwon (posted 2020-02-03 03:26:15.293)

When I modulate the light with sinusoidal pattern using LN81S-FC, Is it necessary to control bias voltage of LN81S-FC? This modulator will experience temperature change. If I need to control bias control to compensate the temperature effect, then what should I do? Can you support any electric board to control bias voltage?

YLohia (posted 2020-02-03 11:52:42.0)

Thank you for contacting Thorlabs. We do recommend using a bias controller for the intensity modulators, especially for applications where the ambient temperature will be unstable. We offer the MBX bias controller for this.

user (posted 2019-12-23 21:54:52.6)

too expensive

YLohia (posted 2019-12-26 04:16:51.0)

Thank you for your feedback. We are sorry to hear that you find our lithium niobate modulators too expensive. If you are looking to use this in an OEM application and/or are looking to purchase a large quantity, please email us at Sales-TQE@thorlabs.com to discuss volume pricing.

Alexey Kokhanovskiy (posted 2019-12-01 23:40:37.953)

Dear Sir/Mme Could you recommend a controller for bias voltages applied to IQ modulator DC bias input ports? With respect, Alexey Kokhanovskiy

llamb (posted 2019-12-04 04:35:36.0)

Hello Alexey, thank you for contacting Thorlabs. We do not have a recommended bias voltage controller for the LN86S-FC; a controller that meets our DC Bias voltage specs will suffice.

Muhammad Adeek (posted 2019-09-16 19:36:09.46)

Dear Representative, I want to purchase an optical modulator that must support 10GHz pulses for setting up the Phase-OTDR system. Kindly guide me which out of the three models (LN82S-FC, LN81S-FC, LN53S-FC) are suitable in my case?

YLohia (posted 2019-09-16 03:01:35.0)

Hello, thank you for contacting Thorlabs. The first two are intensity modulators while the third is a phase modulator. I have reached out to you directly to discuss your application further.

gregory.gaeumann (posted 2018-08-31 11:52:53.037)

Hello, I would like to use your 10 GHz Phase modulator to generate large phase modulations (for serrodyne frequency shifting). Unfortunately, the maximal RF input power is limited to 24 dBm, which is quite low. Is this limit really critical or does it only lead to a slow warm-up of the device? In case it is critical, can you tell me the limiting factor? Thank you.

llamb (posted 2018-09-07 11:21:10.0)

Thank you for contacting Thorlabs. We have only qualified these devices up to 24 dBm for the RF input power and for lifetime testing. The primary limiting factor is the termination circuit that utilizes thin film resistors. These resistors should be able to handle higher power levels if the device is properly heat sunk. I will reach out to you directly to discuss your application and some limitations further.

mchen (posted 2018-05-22 15:06:44.77)

Hello, If using LN66S-FC or LN27S-FC at 1064nm, how high the insertion loss roughly will be? Thanks, Mike

YLohia (posted 2018-05-22 04:54:09.0)

Hello Mike, thank you for contacting Thorlabs. At 1064 nm, while these modulators can technically be used, the waveguides will definitely not be single mode; they will be multi-mode due the cut-off wavelength being specified at 1290-1450 nm. The insertion loss, modulation efficiency (Vpi), extinction ratio, etc. will all change considerably from the values that we specify at 1550nm. Unfortunately, we have not performed testing outside of the specified operating wavelength range.

hnguyen43 (posted 2018-05-07 11:00:34.96)

Can this modulator work for the wavelength range between 1100-1180nm? If not, can you customize an intensity modulator for that wavelength range?

YLohia (posted 2018-05-09 10:29:58.0)

Thank you for contacting Thorlabs. At 1100-1180 nm, while these modulators can technically be used, the waveguides will definitely not be single mode; they will be multi-mode due the cut-off wavelength being specified at 1290-1450 nm. The insertion loss, modulation efficiency (Vpi), extinction ratio, etc. will all change considerably from the values that we specify at 1550nm. Unfortunately, we are unable to offer a custom GHz modulators based on wavelength range at the moment.

jlpeng (posted 2018-03-09 08:26:35.26)

This is not phase and intensity modulator, but phase or intensity modulator. I need an integrated phase and intensity modulator with compact package, i.e. a modulator can change the phase and the amplitude of input light signal. Do you have such kind of modulator(PM fiber pigtailed, bandwidth DC-10 MHz)?

YLohia (posted 2018-03-16 10:17:22.0)

Hello, thank you for contacting Thorlabs. Are you looking to control the phase and intensity independently or simultaneously? The LN86S-FC is the only modulator we currently offer that can be used to modulate the intensity and phase of light simultaneously (but not independently) with the proper biasing and drive signals. This may require fairly complex drive and bias control depending on the desired output. This style of modulator has been used for advanced telecommunication modulation schemes (for example, 16-QAM). If you wish to control the intensity and phase independently using our parts, you will have to cascade two different intensity and phase modulators.

cristhian_alex19 (posted 2018-02-20 12:20:49.237)

Hello! Please tell me what would be the optimal voltages that should enter the iq modulator from the BIAS,to work as a phase or intensity modulator in the LN86-S modulator?

YLohia (posted 2018-04-09 05:47:34.0)

Hello, thank you for contacting Thorlabs. I will reach out to you directly to get more details about your application to better answer your question.

akg (posted 2018-01-31 22:22:19.57)

Hello, I am looking for a setup which looks like: SFL1550P ---> LN82S-FC (or LN81S-FC) ---> LN53S-FC Please suggest if there will be issues in above interconnections. Specifically input of LN53S-FC is polarization maintaining while the output of LN82S-FC is not. Please comment on this and contact me as I wish to proceed quickly. Atul

tfrisch (posted 2018-02-06 10:04:01.0)

Hello Atul, thank you for contacting Thorlabs. You will need to be sure that the SM fiber of LN82S-FC launches the light aligned to the PM ax is of LN53S-FC. This could be achieved with a fiber polarization controller. Alternatively, we are able to offer LN82S-FC with a PM fiber on both the input and output. I will reach out to you directly to discuss which of these options is more suitable for your application.

jason.a.willis99 (posted 2018-01-04 14:32:16.553)

Could you please send me the application note for this product?

tfrisch (posted 2018-01-04 03:06:47.0)

Hello, thank you for contacting Thorlabs. I will send you the application note as well as a link to our Lab Fact presentation which has some information on driving modulators which may be relevant to these amplitude modulators as well as the phase modulators used in the experiment.

arjan.meskers (posted 2017-07-21 15:50:31.39)

The description states "PM input fiber pigtail and a SM output fiber pigtail." PM fibers are by definition single mode (i.e. SM), however SM fibers are not by definition polarization maintaining. It is not clear to me if the output fiber is also polarization maintaining, this also holds for the product '10 GHz Intensity Modulator, Zero Chirp'. Could you clarify the type of output fiber?

tfrisch (posted 2017-07-26 01:11:34.0)

Hello, thank you for contacting Thorlabs. The input fiber is polarization maintaining as the modulation will only occur for one linear input state. The output will be modulated, but since a single mode (and not PM) fiber is used, the polarization of the modulated signal can vary with stress and bends in the fiber. We can offer versions that have PM fibers on both sides as a custom if you need. I will reach out to you directly as well.

user (posted 2017-07-21 07:25:06.81)

For the phase and intensity modulators you should offer them with FC/APC connectors and/or not connectorized as depending on the system they will be used in the reflection from the end face of the connector will cause feedback.

tfrisch (posted 2017-07-26 01:44:08.0)

Thank you for contacting Thorlabs. We can offer these connectorized according to your needs. Please email TechSupport@Thorlabs.com for a quote.

benjamin.haylock2 (posted 2017-05-04 15:46:46.647)

Is it safe to solder the DC pins?

nbayconich (posted 2017-05-22 09:43:08.0)

Thank you for contacting Thorlabs. The pins on our Lithium Niobate Intensity Modulators are intended to be soldered. A Techsupport representative will contact you directly.

nasertrus (posted 2017-03-21 08:43:05.833)

Hello! How to manage optical modulator LN82S-FC? It have SMP connector and 4 pin? What I must do to modulate input signal? Sorry, but I can't find this information in the Manual.

tfrisch (posted 2017-03-30 05:10:52.0)

Hello, thank you for contacting Thorlabs. I see you have already been in contact with a member of our Technical Support Team about the pin diagrams and operation techniques.

mlaroton (posted 2017-03-15 08:24:51.667)

Hi, do your 10 GHz intensity modulators (LN82S-FC, or LN81S-FC) include a built-in polarizer? We plan to use them in a double pass setup with a reflection upon a faraday mirror so it is crucial that both polarizations can circulate through the device. Thank you very much, Miguel

tfrisch (posted 2017-03-15 09:38:00.0)

Hello, thank you for contacting Thorlabs. While these modulators do not have internal polarizers, they are sensitive to polarization. Furthermore, they are not fully bidirection, and performance would be very limited in the reverse direction. I will reach out to you directly with details.

yingwah.wu.civ (posted 2016-09-27 18:14:56.25)

Can LN65S-FC be used for transceiver pair for delay line purpose? Thanks,

jlow (posted 2016-10-05 02:06:00.0)

Response from Jeremy at Thorlabs: I will contact you directly about your application.

saranha1001 (posted 2016-07-12 10:44:28.417)

What is the polarization dependent loss of this product? I couldn't find it in the spec.

user (posted 2016-06-20 15:38:57.803)

Hello, What is the phase transition in this modulator? Is it standard 2 state 180 deg. or it's controlled by RF signal bias?

besembeson (posted 2016-06-22 09:23:40.0)

Response from Bweh at Thorlabs USA: No it is not a two state modulator. The phase is controlled by the RF signal input.

user (posted 2016-06-20 13:02:19.567)

Hello, It seems like my int. modulator react only for increasing slope of modulating RF signal (3,5-4,5V, 0-15Mhz, square signal). (Modulated signal is similar to triangles). I would like to ask, is it too low rf signal frequency, or maybe this modulator feature is to react only for that slope? But if yes, then how to demodulate logical 0 ?

besembeson (posted 2016-06-22 09:12:51.0)

Response from Bweh at Thorlabs USA: Please contact me at techsupport@thorlabs.com to further discuss your application.

yue.s (posted 2016-05-19 06:06:14.71)

What is the max input optical power for the intensity modulator LN82S-FC? moreover is the RF and DC voltage mentioned in the spec are the average value or the peak value?

besembeson (posted 2016-05-19 04:11:36.0)

Response from Bweh at Thorlabs USA: We recommend keeping the input power to under 100mW. That is the RMS voltage.

stefano.minardi (posted 2015-11-19 12:45:30.847)

Dear Sirs, In order to select the RF driver I should use for the NL05-FC amplitude modulator at 30GHz, I would need the RF input power in dBm. Could you please provide this value? Thank you and best regards Stefano Minardi

besembeson (posted 2015-11-20 11:48:33.0)

Response from Bweh at Thorlabs USA: If you are using a sinusoidal signal, with the 10V peak to peak maximum input voltage, the maximum RF power you would need will be about 24dBm. In practice you would not need up 10V (especially if you only need half-wave) so the power will be lower than this.

tbarrett (posted 2014-01-08 13:37:44.233)

Does this product have a users manual?

jlow (posted 2014-01-09 04:08:34.0)

Response from Jeremy at Thorlabs: The LiNbO3 modulators come with a characterization sheet with a drawing showing the pin-outs of the modulators. There's no user manual but I will send to you an application note for your reference.

blwpgs (posted 2013-07-29 11:49:45.217)

Hello! Please tell me what the nominal the bias voltage at the modulator LN05S-FC? (DC Bias Voltage) On your website I can not find this information. In the Data datasheet does not say anything about the bias voltage (minimum, maximum). Please let me know in what range are the data voltage. Best regards, Alex.

jlow (posted 2013-08-01 10:31:00.0)

Response from Jeremy at Thorlabs: The modulator is set to be on the negative slope when used with 0V bias. However, one would generally use a feedback loop to control the DC bias voltage to minimize DC drift. The DC bias voltage range should be -8V to 8V.

tcohen (posted 2012-12-28 13:06:00.0)

Response from Tim at Thorlabs: This is a Mg doped LiNbO3 crystal. This material will form color centers when exposed to light at 780nm, causing higher loss. This is temporary as charge carriers become displaced and trapped in defects, forming dipoles within the crystal, and may be removed by heating. For modulation, there are suitable RF amplifiers available from companies such as SHF, Triquint, Oki, Inphi, Centellax, Picosecond, etc. We will contact you directly to discuss your application in more detail.

gnishi (posted 2012-12-17 00:46:58.797)

Dear Sir: I have a question on the modulator. (1) Can it be used for the modulation with 780nm wavelength? If so, is there any problem with such wavelength region or anything to concern for the opearation? (2) Do you have a product for driving this modulator? Thank you for advance.

jlow (posted 2012-10-25 11:40:00.0)

Response from Jeremy at Thorlabs: The typical Vpi is about 9-10 Volts at 30GHz. The maximum voltage is 14Vp-p for frequencies > 30GHz and about 10Vp-p for frequencies < 30GHz. Therefore the 2pi phase modulation at 30GHz exceeds our normal maximum RF power (the limiting factor is the power handling capability of the internal termination). We might be able to provide a customized option for higher RF powers at high frequencies. I will get in contact with you directly regarding this possibility.

sz292 (posted 2012-10-19 11:54:56.99)

hi, I am about to buy one 40GHz Phase Modulator, I am wondering what is the maximum phase modulation it can reach？ is 2pi possible?

bdada (posted 2012-03-21 18:02:00.0)

Response from Buki at Thorlabs to ok: Thank you for participating in our feedback forum. We have contacted you to discuss your application to make sure the LN66S modulator is suitable and to provide additional support. Please note that the "Overview" and "Specs" tab on this web page provide the specifications you requested.

ok (posted 2012-03-18 13:12:14.0)

Whom it may concern, Sir, I am a regular purchaser of your products. Now we need some device to spread the spectrum of our optical pulse (output of semiconductor laser; 10ns-pulses with 100Hz-rep.rate and max.power near of 1W). Looks like LN66S is good for this purpose. It is a quite new issue for me, so I need to know some questions: - how much is maximum applicable RF Drive Voltage? - is negative value of RF Drive Voltage acceptable or it should be positive pulses only? - is some DC Bias necessary or we can operate without it? - could you give a definition of of Insertion Loss Variation? Do you mean optical losses? Would you be so kind as to answer it? Thank you in advance, Oleg Kulagin Senior Scientist Institute of Applied Physics

tcohen (posted 2012-02-28 11:36:00.0)

Response from Tim at Thorlabs: The LN27 and LN66 are high-speed phase modulators. A single device imparts pure phase modulation on the optical carrier. In that sense they can be considered as frequency shifters as energy is transferred from the optical carrier into the modulation sidebands. However, this is probably not the frequency shifting that you had in mind, as all energy is transferred symmetrically to +/- sidebands around the carrier -- it is not true frequency shifting. If you want to shift the energy from the optical carrier into just one modulation sideband, this type of modulation is called single-side band suppressed carrier (SSB-SC) and the LN86 is the appropriate device for this. By proper DC biasing each of the Mach-Zehnders and phasing of the RF drive signals SSB-SC can be obtained. This acts as a true frequency shifter and the amount of frequency shift is determined by the RF modulation frequency. I have contacted you directly with some more information.

a.j.h.meskers (posted 2012-02-28 07:40:37.0)

Dear Sir/Madam, In the specifications of product LN27S-FC is stated that this device could also shift the optical frequency. How does this exactly work? Could you give me some more information regarding this frequency shifting operation? Kind regards, Arjan Meskers

bdada (posted 2011-11-01 12:37:00.0)

Response from Buki at Thorlabs: Thank you for your feedback. Our production team will review your suggestion. Please contact TechSupport@thorlabs.com if you would like to discuss your application further.

user (posted 2011-10-31 12:57:03.0)

Please look at adding a SMA to SMP connector as you sell SMA cables but not SMP.

jjurado (posted 2011-06-15 09:54:00.0)

Response from Javier at Thorlabs to jikim: Thank you very much for contacting us. At the moment, we do not have the capability to offer such a product. Free-space modulators do not have the capability to achieve 40 dB extinction ratio performance, and producing a fiber coupled LN-type modulator with free-space output would require a significant amount of development. Alternatively, we could supply a short length of PM fiber at the output pigtail, which could be then fitted with a collimator. However, we cannot commit to a 40 dB PER specification. I will contact you directly to get more details about your application.

jikim (posted 2011-06-14 15:17:06.0)

Could you provide a customized phase modulator with a PM input (FC/APC) and a free space collimated output to obtain the linear polarization output with extinction ratio more than 40 dB and without ellipticity? In the fiber output there exists thermal effects.

jikim (posted 2011-03-08 16:13:26.0)

Is a zero chirp intensity modulator (LN56S-FC) with a PM fiber in the output available? I would appreciate if you could send me a quotation for it.

user (posted 2011-02-13 22:03:34.0)

jjurado (posted 2011-02-07 10:26:00.0)

Response from Javier at Thorlabs to jikim: Thank you very much for submitting your inquiry. The LN53S does not rotate polarization. However, it functions as a variable waveplate, just like a Soleil-Babinet Compensator, when a voltage is applied to the modulator. The voltage changes the relative retardance between two orthogonal polarization modes. No intensity modulation would be observed if the input polarization is perfectly linear *and* if the linear polarization is launched on-axis to the PM input fiber. It is possible that the input polarization is not linear and/or not launched on axis to the modulator. Small misalignments between the PM fiber and LN crystal will create a small intensity modulated signal when passed through a linear analyzer. Also, use of single mode fiber at the output will allow the amplitude of the intensity modulated signal you observed to vary; just gently press on the fiber. The LN65S modulator, with an internal polarizer, will greatly suppress the undesired intensity modulation. If you need to retain the state of polarization at the output of the modulator, PM output fiber should be used. Also, this modulator can be supplied with FC/APC connectors.

jikim (posted 2011-02-04 17:31:35.0)

I have a question on the output polarization of the phase modulator. A simple experiment has been performed. A single mode laser beam with linear polarization passes through a LN53S-FC modulator to which a sinusoidal signal at few tens of MHz is applied. The output of the modulator passes through a linear polarizer, i.e. a polarization analyzer. A photo diode (PD) observes the intensity of the transmitted beam through the polarizer. Then I could observe the same sinusoidal signal at the PD indicating that the output polarization of the modulator is varied with respect to the phase modulation. Such polarization variation of the output is absolutely not desirable in my application. When a PM fiber is used in the output port of the phase modulator instead of a SMF, is there any polarization change depending on the phase modulation? Or is there any suggestion from you to escape such a polarization change?

jjurado (posted 2011-02-02 11:54:00.0)

Response from Javier at Thorlabs to jikim: Thank you very much for submitting your inquiry. We can certainly provide an LN65S-FC modulators with PM input and output fiber pigtails. I will contact you directly with pricing and lead time information.

jikim (posted 2011-02-02 16:14:34.0)

Could you provide a LN65S-FC with PM fibers in both input and output ports?

Thorlabs (posted 2010-10-19 19:23:08.0)

Response from Javier at Thorlabs to jikim: There are some slight differences between the x-cut (LN56/LN81) and z-cut (LN63/LN82) 10G intensity modulators, but the variation in the Vpi of the RF port is typically in the following range: DC to 1 GHz = 5V, 3GHz = 5.5V, 10 GHz = 7V. Note, the Vpi @ DC quoted in the specification sheet is for the DC bias port - not the RF port. The Vpi of the RF port is tested and specified with a 10Gb/s pseudo-random bit sequency (PRBS) which has a frequency spectrum that is roughly equivalent to a fixed frequency in the 3-4 GHz range, that is why the Vpi @ 3 GHz above is indicated as being equivalent to the Vpi for the 10 Gb/s PRBS.

jikim (posted 2010-10-19 11:00:14.0)

According to the specification, the Vp is mentioned to be in the range of 3 to 8 V. Could you show the frequency dependence of such a voltage on the frequency (from 0 to 10 GHz)?

Thorlabs (posted 2010-10-11 17:47:13.0)

Response from Javier at Thorlabs to jikim: We can certainly quote a special FC/APC version of the LN53S-FC. I will contact you directly with more information.

jikim (posted 2010-10-11 13:02:11.0)

Is it possible to make FC/APC instead of FC/PC connector of this phase modulator (LN53S-SC)?

Thorlabs (posted 2010-10-07 15:08:16.0)

Response from Javier at Thorlabs to Andres: I will contact you directly to discuss your application. We have to first consider your lasers wavelength and power output, among other parameters.

andres.aragoneses (posted 2010-10-07 11:57:04.0)

Dear sir/madam I need an optic amplifier that multiplies the intensity of one laser an integer number of times (2, 3 or 4). Which is the product I need? thank you Aragoneses

Adam (posted 2010-05-06 16:24:13.0)

A response from Adam at Thorlabs: We are working on getting these drawings on the web. In the meantime, if you need the drawings please email techsupport@THorlabs.com and we will provide with the necessary documentation.

user (posted 2010-05-05 21:38:35.0)

can you please provide mechanical drawings for those products?

Intensity Modulators

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Lithium Niobate Intensity Modulator Diagram

Click to Enlarge
This operational diagram of an intensity modulator shows the waveguide (blue lines) splitting into two paths embedded in the surface of the lithium niobate (green). The input light is first affected by the modulating RF drive voltage and then the DC bias voltage, as shown by the translucent regions.

Applications

RF-Over-Fiber (RFOF) and Microwave Photonics
High-Speed Telecommunications
WDM Transmission

LiNbO₃ optical intensity modulators use a Mach-Zehnder interferometer structure to allow modulation of the optical output power of the device, as shown by the operational diagram to the right. The devices include two electrical ports: one for the modulation driving signal and one for biasing the modulator. X-cut or Z-cut devices are available.

X-cut devices allow for both arms of the Mach-Zehnder interferometer to be symmetrically modulated. This symmetry ensures that the modulated output is not also shifted in phase/frequency (chirped).

Z-cut devices have an inequality in the push-pull phase shift between the two arms of the Mach-Zehnder interferometer. This results in a phase/frequency shift (chirp) in the output in addition to the intensity modulation. Z-cut devices also have a better overlap of the electrical and optical fields in the Mach-Zehnder structure, resulting in higher drive efficiencies.

The LN81S-FC and LN82S-FC 10 GHz modulators include an integrated photodetector for optical power monitoring and modulator bias control, eliminating the need for an external fiber tap.

Thorlabs offers two high-speed intensity modulators that can operate up to 40 GHz. The LN05S-FC modulator is a high bandwidth device designed to provide minimum variation in modulation over the operating frequency range. The LNLVL-IM-Z modulator provides the lowest RF V_π, or half-wave voltage, at any specific frequency over the operating frequency range. The graphs below show a typical drive voltage (left) and electro-optic response (right) over the operating frequency range for these two modulators. See the Specs tab for complete specifications.

Click to Enlarge

Click to Enlarge

Phase Modulators

Zoom

Click to Enlarge
This operational diagram of a phase modulator shows the waveguide (blue line) as one through optical path embedded in the surface of the lithium niobate (green). The input light is affected only by the modulating RF drive voltage, as shown by the translucent region.

Applications

Chirp Control for High-Speed Communications
Coherent Communications
Optical Sensing

LiNbO₃ optical phase modulators consist of a single, through optical waveguide, as shown by the operational diagram to the right. As there is only one optical path to modulate, all of the phase modulators are Z-cut devices in order to optimize drive efficiency.

While most applications benefit from the integrated polarizer in Z-cut modulators, the LN53S-FC and LN66S-FC modulators are offered for applications where the polarizer is undesirable.

IQ Modulator

Zoom

Click to Enlarge
This operational diagram of an IQ modulator shows the waveguides (blue lines) split into four paths embedded in the surface of the lithium niobate (green). The input light is first affected by each MZI's modulating RF drive voltages, and then by each MZI's DC bias voltages, as shown by the translucent regions.

Dual, Parallel MZIs on a Single X-Cut Lithium Niobate Chip

Applications

Coherent Communications, Including QPSK and DQPSK Encoding
Single Side Band Suppressed Carrier (SSB-SC) Transmission

LiNbO₃ IQ modulators use a dual-parallel Mach-Zehnder interferometer (MZI) structure in order to allow modulation of both the phase and amplitude of light for advanced optical transmission schemes. As shown in the operational diagram to the right, the modulator consists of two independently-controlled MZIs whose outputs are combined. The combining structure also includes a bias electrode that applies a phase delay between the two MZIs, allowing for the required phase control between the two modulator arms.

Two IQ modulators can be used together in a polarization-multiplexed arrangement to double data transmission rates, e.g. two LN86S-FC devices can provide a 40 Gb/s link on the same optical channel/wavelength.