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40 GHz or 40 Gb/s Lithium Niobate Modulators

  • 40 GHz Phase or Intensity Modulators
  • 40 Gb/s DQPSK/4QAM Modulator
  • FC/PC Connectors


40 Gb/s DQPSK Modulator


40 GHz Phase Modulator without Polarizer

FC/PC Connectors

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40 GHz Phase and Intensity Modulators

Item # LN05S-FC LN27S-FC and LN66S-FC
Operating Wavelengtha 1525 - 1605 nm 1525 - 1605 nm
E/O Bandwidth (-3 dB) 35 GHz (Typ.) 35 GHz (Typ.)
RF Vπ (Typical) 5.5 V @ 1 GHz 7.5 V @ 30 GHz
  • The modulator is 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.


  • 40 GHz Phase or Intensity Modulators
  • C- and L-Band Operation
  • Phase Modulators Available With or Without Optical Polarizer
  • Hermetically Sealed Packaging


  • Chirp Control for High-Speed Communications
    - SONET OC-768 Interfaces
    - SDH STM-256 Interfaces
  • Coherent Communications
  • Optical Sensing
  • All-Optical Frequency Shifting

The LN05S-FC, LN27S-FC, and the LN66S-FC are 40 GHz modulators manufactured by Thorlabs. These three revolutionary, high-performance, titanium-indiffused Z-cut lithium niobate optical modulators were designed for ease of system integration; they offer large bandwidths and are ideal for developing high-speed modulation systems.

The LN05S-FC intensity modulator with external DC bias is a high-performance 40 GHz modulator that has a single-ended drive configuration with a fixed chirp coefficient of ±0.7. The LN05S-FC has a Mach-Zehnder interferometric architecture with external DC bias, ideal for both NRZ and RZ data format solutions. The LN27S-FC and the LN66S-FC are high-performance 40 GHz phase modulators, allowing for chirp control in high-speed data communications. These modulators, which can support data rates up to 43 Gb/s, are also ideal for applications in coherent communications, sensing, all-optical frequency shifting, and data encryption.

The LN27S-FC and LN66S-FC modulators both offer internal RF terminations, but the LN27S-FC also offers an optical polarizer not included with the LN66S-FC. All three modulators are based on Z-cut titanium-indiffused LiNbO3 and are hermetically packaged in a dual-port housing with PM and SM fiber pigtails on the device input and output, respectively. The fiber pigtails are offered connectorized with FC/PC connectors. Please note that polarization-maintaining fiber and a full range of connectorization options are available for all Lithium Niobate Modulators. Please contact Tech Support for assistance and details.

Item # LN05S-FC LN66S-FC and LN27S-FC
Parameters Min Typ. Max Min Typ. Max
Optical Specifications
Operating Wavelengtha 1525 nm - 1605 nm 1525 nm - 1605 nm
Optical Insertion Loss - 4.5 dB 5.5 dB - 4.0 dB 4.5 dB
Optical Return Loss 40 dB - 40 dB - -
Optical Extinction Ratio (@ DC) 20 dB - - N/A N/A N/A
Optical Input Power - - 100 mW - - 100 mW
Electrical Specifications
E/O Bandwidth (-3 dB) 30 GHz 35 GHz - - 35 GHz -
Operating Frequency Range DC to 40 GHz (Min) DC - 40 GHz (Typ.)
RF Vπ - 5.5 V @ 1 GHz 6.0 V @ 1 GHz - 7.5 V @ 30 GHz 9.5 V @ 30 GHz
DC Bias Vπ (@ 1 kHz) 3.5 V 5.0 V N/A N/A N/A
S11 (DC to 30 GHz) - -12 dB -10 dB - -12 dB -10 dB
S11 (30 GHz to 40 GHz) - -10 dB -8 dB - -10 dB -8 dB
RF Port Input Power - - 24 dBm - - 24 dBm
Mechanical Specifications
Crystal Orientation Z-cut
RF Connection Female 1.85 mm (V)
Fiber Type Input: PANDA Polarization Maintaining
Output: SMF-28® Single Mode
Fiber Lead Length 1.5 m (Typ.)
Environmental Specifications
Operating Temperature 0 °C - 70 °C 0 °C - 70 °C
Storage Temperature -40 °C - 85 °C -40 °C - 85 °C
  • The modulator is 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.

RF Input

Anritsu V™ Type Female

SMA Female

DC Bias

SMA Female

SMA Female

Posted Comments:
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.
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.
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 for a quote.
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.
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.
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
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
LN05S-FC Support Documentation
LN05S-FC40 GHz Intensity Modulator with Polarizer, FC/PC Connectors
Lead Time
LN27S-FC Support Documentation
LN27S-FC40 GHz Phase Modulator with Polarizer, FC/PC Connectors
LN66S-FC Support Documentation
LN66S-FC40 GHz Phase Modulator without Polarizer, FC/PC Connectors

40 Gb/s DQPSK/4QAM Modulator

Parameter Min Max
Operating Wavelengtha 1525 nm 1575 nm
Optical Extinction Ratio (Typical) 20 dB -
E/O Bandwidth (-3 dB) (Typical) 14.0 GHz -
RF Port S11 (0.05 MHz to 10 GHz) - -10 dB
RF Detector Threshold - 0.5 V
  • See Note Below


  • Dual, Parallel MZIs on a Single X-Cut Lithium Niobate Chip
  • Separate DC Bias for Both MZIs
  • High Reliability
  • Long-Term Bias Stability
  • Hermetically Sealed Packaging
  • Can be used in (D)QPSK and SSB-SC Transmission for Telecom

The LN86S-FC is a Dual-Parallel, Titanium-Indiffused, X-Cut Lithium Niobate Modulator. It is capable of providing a 40 Gb/s signaling rate and offers a large bandwidth to benefit customers developing high-speed modulation systems. Each Mach-Zehnder Interferometer (MZI) has an independently-controlled bias section to achieve maximum performance. The front end of the modulator consists of two MZIs in parallel. Each MZI is an intensity modulator with separate external DC bias controls, giving the user the ability to perform multi-level signaling. The back end of the LN86S-FC is a phase modulator which allows for the required phase control in the signal channel. The LN86S-FC is designed for quadrature modulation (QPSK or 4QAM) and single side-band suppressed carrier (SSB-SC) transmission. This modulator is part of a family of high-performance, Telcordia-compliant, external optical modulators with industry-leading long-term stability. It is hermetically packaged in a durable housing with PM and SM fiber pigtails on the device input and output, respectively. The standard device has fiber pigtails connectorized with FC/PC connectors. Please contact Tech Support for customization of these products.

Mach-Zehnder Modulator Operation

Dual Modulation Schematic

In this dual-parallel modulator, the incoming signal is equally split into two legs and sent through separate intensity modulators. Each intensity modulator can be modulated with a DPSK format. The outputs of each intensity modulator's legs are re-combined then sent through a low speed phase modulator. The phase modulator serves the purpose of applying a phase delay between the legs. The resultant output of the phase modulation section is then recombined and can form a DQPSK signal.

Note: The modulator is designed for use at 1550 nm. Using the modulator at another wavelength may cause a temporary increase in loss that is not covered under warranty. For instance, the increase in loss caused by shorter wavelengths can be reversed by heating the modulator to 50 °C for an hour.

Item # LN86S-FC
Parameter Min Typ Max
Optical Extinction Ratio (@ DC)a 20 dB - -
Optical Insertion Loss (Connectorized) (I.L.) - 5 dB 6 dB
Insertion Loss Variation (EOL) (Δ I.L.) -0.5 dB - 0.5 dB
Optical Return Loss 40 dB - -
Operating Wavelength (λ)a 1525 nm - 1575 nm
Operating Case Temperature (TCASE) 0 °C - 70 °C
Storage Temperature -40 °C - 85 °C
Vπ RF Ports (@ DC) - 3.5 V 4.5 V
Vπ RF Ports (@ 1 GHz) - 4.5 V 6 V
Vπ RF Bias Ports (@ DC) - 4.5 V 5.5 V
RF Port S11 (0.05 MHZ to 10 GHz) - -12 dB -10 dB
Fiber Lead Length - 1.5 m -
RF Parameters
RF Input Power - - 24 dBm
E/O Bandwidth (-3 dB) (Fc-3 dB) 14.0 GHz - -
S21 Amplitude difference (50 MHz to 20 GHz) -1.5 dB - -1.5 dB
S21 Phase Difference (50 MHz to 14 GHz) -10° - 10°
S21 Phase Ripple (50 MHz to 10 GHz) -10° - 10°
Differential RF Delay -5 ps - 5 ps
Phase Modulator
DC Vπ - - 6 V
E/O Bandwidth 1 MHz - -
RF Detectors
Threshold - - 0.5 V
Slope 0.1 V/Vpp - 0.4 V/Vpp
Linearity -5% - 5%
  • The modulators are designed for use in the 1550 nm window. Using a modulator at another wavelength (e.g., visible light) may cause a temporary increase in loss that is not covered under warranty. For instance, the increase in loss caused by shorter wavelengths can be reversed by heating a modulator to 50 °C for an hour.

RF Input

GPO Connector


Posted Comments:
No Comments Posted
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
LN86S-FC Support Documentation
LN86S-FC40 Gb/s DQPSK Modulator, FC/PC Connectors
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