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High-Speed, Fiber-Optic, Linear Reference Transmitters

  • Linear Reference Transmitters with 35 or 65 GHz Analog Bandwidth
  • Integrated Linear RF Amplifier and Modulator with Bias Control
  • Integrated C-Band Tunable, L-Band Tunable, or 1310 nm Laser
  • Support PAM4 Modulation up to 64 Gbaud/s


65 GHz Reference Transmitter, 1310 nm Internal Laser


35 GHz Reference Transmitter, C-Band Internal Laser

32 Gb/s Eye Diagram from MX35E

Related Items

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All Reference Transmitters Include:

  • Mach-Zehnder Intensity Modulator
  • Bias Controller with Manual and Fully Automatic Operation Modes
  • RF Amplifier
  • Integrated C-Band Tunable, L-Band Tunable, or 1310 nm Fixed-Wavelength Laser (Contact Tech Support for an 850 nm Fixed-Wavelength Laser)
  • Variable Optical Attenuator (VOA) for Automatic or Manual Power Control
Key System Specificationsa
Item # MX35E Series MX65E Series
Amplifier Type Linear (Analog)
Bandwidth 35 GHz (Typical) 65 GHz (Typical)
Typical Frequency Response
(Click Icon to View Graph)
MX35E Frequency Response MX65E Frequency Response
Internal Laser Wavelength C-Band, L-Band, or 1310 nmb C-Band, L-Band, or 1310 nm
Internal Laser Output Power 13.5 dBm (Typical)
External Input Laser Wavelength Rangec 1250 nm - 1610 nm
RF Amplifier Gain 10 dB to 23 dB 11 dB
Low Frequency Cutoff 200 kHz 70 kHz
Optical Extinction Ratio 13 dB (Typical)
Modulator Type Intensity
  • For additional specifications, see the Specs tab and the manuals.
  • Please contact Tech Support to order an MX35E transmitter with an 850 nm fixed-wavelength internal laser.
  • User-Provided
Linear Reference Transmitter Eye Diagram
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20 Gb/s NRZ Eye Diagram from MX35E Series
Linear Reference Transmitter PAM4 Multi-Level Eye Diagram
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25 GBaud/s PAM4 Eye Diagram from MX35E Series
Linear Reference Transmitter Eye Diagram
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40 Gb/s NRZ Eye Diagram from MX35E Series
Linear Reference Transmitter PAM4 Multi-Level Eye Diagram
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56 GBaud/s PAM4 Eye Diagram from MX65E Series


  • Turnkey Reference Transmitter Solution
  • Linear RF Amplifier
  • Integrated Laser, Intensity Modulator, and Optical Power Control
  • External Loop-Back Cables Support Custom Configurations
  • Control via Intuitive Touchscreen Interface or Remotely Using USB or RS-232 Connections
  • Custom Systems Available by Contacting the Ultrafast Optoelectronics Team

Thorlabs' all-in-one linear reference transmitters are based on proven lithium niobate (LiNbO3) modulator technology driven by high-fidelity RF amplifiers. They are designed for high-speed fiber optic test and measurement applications. These user-configurable systems integrate a Mach-Zehnder intensity modulator (MZM) with fully featured bias control, a tunable or fixed-wavelength laser source, RF amplifier, and variable optical attenuator. These instruments are ideal for use in either an R&D laboratory or in a manufacturing environment for linear applications that require frequency responses up to 35 GHz (MX35E series) or 65 GHz (MX65E series), including high bit-rate modulation schemes that rely on multi-level encoding, such as PAM4.

The transmitters on this page are based on the use of an RF amplifier that provides a linear relationship between the input and output voltages. Note, however, that the linear range of the whole system is still limited by the non-linear response of the lithium niobate (LiNbO3) modulator. As a result, large RF output signals will experience some compression, which can be advantageous in some applications.

Internal Laser
Each reference transmitter has a built-in telecom-grade laser. Internal C- and L-band lasers are tunable on the ITU 50 GHz grid. A dither feature for wavelength stabilization is available in both tunable internal laser options (see the Operation tab for more information). An internal 1310 nm fixed-wavelength laser is also available as an option for all reference transmitters. MX35E series reference transmitters with an integrated 850 nm fixed-wavelength laser are also available upon request (contact Tech Support). An external laser source between 1250 and 1610 nm can also be used to provide the optical input.

System Connections
The laser input port uses PM fiber with light linearly polarized along the slow axis (aligned to the connector key) and can accept a maximum input power of 20 dBm (100 mW). Each fiber bulkhead accepts FC/PC connectors. The amplifier RF port connector type is either SMA or 1.85 mm (V), depending on the frequency response of the device. See the Front & Back Panel tab for more information.

We offer a selection of microwave cables and adapters for incorporating these transmitters into a system.

These reference transmitters can be controlled in two ways. The simplest method is using the intuitive touchscreen interface, which gives the user complete control over all instrument functionality. These instruments can also be operated remotely via the RS-232 or USB ports on the back panel. The Operation tab describes the graphical user interface (GUI) and user-customizable features, and we provide a remote control user guide and a remote control software tool (see the Software tab) for download.  

We also offer digital reference transmitters with speeds up to 40 Gb/s and optical transmitters based on phase modulators. Please see the Selection Guide tab above for all of our transmitter instruments.

Reference Transmitter Block Diagram
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Block diagram Showing Internal Setup of the High-Speed, Linear Reference Transmitters.
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This plot demonstrates the usable bandwidth provided by each series of linear reference transmitters.
System Specifications
Series MX35E Series MX65E Series
Amplifier Type Linear (Analog)
Usable Bandwidth 35 GHz 65 GHz
Internal Laser Three Options - See Table Below
External Lasera Wavelength Rangeb 1250 nm - 1610 nm
Optical Input Power 20 dBm (Max); 22 dBm (Absolute Max)
Power Calibration Points 1310 nm, 1550 nm, and 1590 nm
Optical Extinction Ratio 13 dB (at 32 Gb/s)
Modulator Type Intensity
Modulator Drive Voltage (Vpi) 5.5 V
Optical Insertion Loss 5 dB (1550 nm); 7 dB (1310 nm)
Small Signal Bandwidthc 35 GHz 60 GHz
Low Frequency Cutoff 200 kHz 70 kHz
System Linearity <3.5% THDd at 1 GHz
Amplifier RF Input 250 mV (Typical)
500 mV (Max)
700 mV (Absolute Max)
500 mV (Typical)
2 V (Absolute Max)
RF Amplifier Gain (Small Signal) 10 dB to 23 dB
(User Adjustable)
11 dB
  • User Provided
  • Using the modulator at wavelengths outside this range may cause an increase in insertion loss and will void the warranty.
  • Linear, Analog Response
  • Total Harmonic Distortion
Linear Reference Transmitter Eye Diagram
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Linear amplifiers provide a linear relationship between voltage input and output. Different line slopes indicate different gain settings in the MX35E series. Gain is user-adjustable in 1 dB increments.
Internal Laser Specificationsa
Item # MX35E
Laser Type C-Band Tunable L-Band Tunable Fixed Wavelength
Wavelength Range 1527.6 - 1565.5 nm 1570.0 - 1608.8 nm 1310 nm
Frequency Range 191.50 - 196.25 THz 186.35 - 190.95 THz -
Optical Output Power 13.5 dBm 13.5 dBm 13.5 dBm
Frequency Accuracy ±1.5 GHz ±1.5 GHz -
Tuning Resolution 50 GHz 50 GHz N/A
Tuning Speed (Between Wavelengths) 10 s 10 s N/A
Side Mode Suppression Ratio 55 dB 55 dB 35 dB (Min)
Optical Signal Noise Ratio 60 dB 60 dB -
Intrinsic Linewidth 10 kHz 10 kHz 2 MHz
Relative Intensity Noise -145 dB/Hz (Max) -145 dB/Hz (Max) -
Back Reflection -14 dB (Max) -14 dB (Max) -
Polarization Extinction Ratio 18 dB (Min) 18 dB (Min) 20 dB
  • Values are typical unless otherwise stated.
Power Monitor and VOAa Specifications
Power Monitor Accuracyb ±0.5 dBm at Power Calibration Points
Power Monitor Resolutionb 0.01 dBm
Power Monitor Insertion Loss 0.1 dB (Typical) per Monitor
VOA Insertion Loss 0.4 dB (Typical)
VOA Response Time 1 s
  • Variable Optical Attenuator
  • Applies to each of the three internal power monitors.
Power and Environmental Specifications
Parameter Min Max
Main AC Voltage 100 VAC 250 VAC
Power Consumption - 60 VA
Line Frequency 50 Hz 60 Hz
Operating Temperature 10 °C 40 °C
Storage Temperature 0 °C 50 °C
Humiditya 5% Relative Humidity 85% Relative Humidity
  • Non-Condensing Environment

System Overview

These Linear Reference Transmitters are fully integrated and contain both the laser source and the lithium niobate (LiNbO3) Mach-Zehnder intensity modulator; the only required external input is the signal source to the Amplifier RF In port. Either the internal laser or an external laser source may be coupled to the Laser In port, which can be seen at the bottom-left corner of the diagram below. This port uses polarization maintaining (PM) fiber with light linearly polarized along the slow axis, as shown on the front panel of the instrument. Optical power is monitored in three places (Monitor 1, Monitor 2, and Monitor 3) for the purpose of enabling bias and power control. These power values are also available at the I/O port. Monitor 1 is at the laser input, Monitor 2 is at the output of the modulator, and Monitor 3 is at the final optical output.

Reference Transmitter Block Diagram
A Block Diagram of the Internal Setup of the High-Speed Reference Transmitters

Instrument Control

The graphical user interface (GUI) gives the user complete control over all instrument functionality. It is a resistive touchscreen display sensitive to both finger pressure and taps from a plastic stylus. The knob on the front panel of the housing can be used in place of the on-screen arrow buttons for quickly changing set-point values. Pressing (clicking) the knob will confirm a new set-point value. Additionally, the instruments can be driven using serial commands delivered via connectors on the rear panel.

The home screen is shown in Figure 1. It is organized into three main sections:

Linear Reference Transmitter Main Menu
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Figure 1: Home Screen of the MX35E Series
  • Left Column:
    • Buttons show the on/off status of the different instrument functions.
    • Tap a button to toggle the function on/off.
  • Middle Column:
    • Current operating parameters of each control function are shown.
    • Tap in this column to access the Settings page for each function.
  • Right Column:
    • Buttons provide access to various utility and help functions.
    • Tap to review and customize system settings.

The green dot that appears in the upper-right of the center column panels indicates that those functions are stable. The dot will blink if that function is still stabilizing. 

Functions and controls enabled by the GUI are further discussed in the following sections.

Laser and System Wavelength Settings

Reference Transmitter System Wavelength Selection Screen
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Figure 3: System Wavelength Selection Screen
Reference Transmitter Laser Settings GUI
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Figure 2: Laser Settings Screen

The laser setting screen shown in Figure 2 is accessed directly from the home screen. Each instrument includes a C- or L-band telecom-style laser that is tunable on the ITU 50 GHz grid or a 1310 nm fixed-wavelength laser. An 850 nm fixed-wavelength laser can be substituted by contacting Tech Support. ITU Channel wavelengths are indexed for convenience; use the arrow buttons to step through the indices to select the desired wavelength. This screen also allows the user to control whether or not the dither feature (available for tunable C- and L-band lasers only) is used to stabilize the wavelength. Turning dither off results in lower phase and intensity noise (see the Specs tab for a representative plot), but doing so may also result in the wavelength drifting slightly over time. If an external laser is used, the internal laser can be turned off by tapping the laser button on the home screen.

If an external laser is used, it may be necessary to change the power monitor calibration settings. These instruments can be used at wavelengths anywhere between 1250 nm and 1610 nm, and calibration settings are supplied for three wavelengths: 1310 nm, 1550 nm, and 1590 nm. These wavelengths represent the centers of the O-Band, C-Band, and L-Band. The default calibration setting corresponds to the wavelength range of the internal laser. If operating outside that wavelength range, change the power monitor calibration settings by tapping the Menu button on the home page. Select the System Wavelength setting, shown in Figure 3, to change the power monitor calibration wavelength to the value closest to the wavelength of the laser source being used.

Reference Transmitter Linear Amplifier Voltage In vs. Voltage Out
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Figure 5: Linear amplifiers provide a linear relationship between voltage input and output. Different line slopes indicate different gain settings in the MX35E series. Gain is user-adjustable in 1 dB increments.
Reference Transmitter Linear Amplifier Settings Screen
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Figure 4: Linear RF Amplifier Settings Screen for the MX35E Series

Linear RF Amplifier

The amplifier used in these reference transmittes is a linear amplifier that accurately reproduces the input signal with minimal distortion. In addition, the MX35E series has adjustable gain that can be controlled from the Amplifier Settings page shown in Figure 4. This allows for linear amplification for a wide range of input signal levels before being applied to the RF input port of the modulator. Figure 5 shows how the gain setting changes the slope of the output vs. input signal relationship. Note, however, that the linear range of the whole system is still limited by the non-linear response of the lithium niobate modulator. See the specifications in the Specs tab and manual for signal limitations in this regard.

Modulator Bias Controller

Intensity Modulator Bias Control Settings
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Figure 7: Bias Settings Screen
LiNbO3 EO Modulator Transmission Function
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Figure 6: Bias Points for an Intensity Modulator, in which Vpi is the Half-Wave Voltage

There are four bias control modes, which provide the option of operating with fully automatic bias control or under manual control. Three of the four automated operating modes, Peak, Quadrature, and Null, reference the regions labeled on the modulation transmission function, which is illustrated in Figure 6. When one of these modes is selected, a dither tone is used to hold the modulator at the respective bias point. The dither tone is part of a lock-in approach that maintains a stable bias point by compensating for modulator drift, which occurs over time due to the temperature sensitivity of the modulator. The dither tone can be set to a frequency between 1 and 10 kHz, and the amplitude of the tone can also be selected. Quadrature mode gives the option of operating on either the positive or negative slope of the function.

For those applications that require an automated, but ditherless, approach to maintaining a stable bias set point, select the Constant Ratio mode. It is enabled by tapping the MAN function on the right of the screen shown in Figure 7 and configuring the Ratio Set Point and Slope values. This mode adjusts the bias voltage to maintain a chosen ratio between the intensity values reported by Monitor 1 and Monitor 2. The Slope setting allows the user to choose whether increasing voltage on the modulator increases or decreases the optical output power.

It can be useful to operate for brief periods of time at a bias fixed voltage and without a dither tone. A fixed bias voltage can applied in one of two ways. When operating in Quadrature, Peak, or Null modes, tapping the value of Dither will toggle it between on and off states. When dither is toggled off, the value of the fixed bias voltage is held at the most recent automated bias voltage. This enables the user to make quick measurements, without the dither tone present, while the modulator is biased at one of the common modulator transmission function set points. The Constant Bias mode can also be accessed by tapping the Mode value and then the MAN function on the right of the screen. This page allows either the automated Constant Ratio or fixed-voltage Constant Bias modes to be enabled and configured.

Variable Optical Attenuator

Reference Transmitter Variable Optical Amplifier Settings
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Figure 8: VOA Settings Screen

The VOA provides the means for adjusting and stabilizing the modulated optical output power. The VOA settings screen, which is shown in Figure 11, allows the user to choose between and adjust the parameters of the two operational modes. In Constant Attenuation mode, the attenuation level between the Return from Modulator input port and the Final Optical Output port is fixed, which allows power fluctuations at the input of the power controller to be transferred to the output. In Constant Output Power Mode, the final optical output power is held constant independent of the input fluctuations. In this mode, the VOA is effectively used as a power stabilizer. Tap the Step function button at the right of the screen to change the step size by which the arrows increment or decrement the set point values.

The VOA settings screen also allows the user to select the units used to report the power readings and parameters on all pages. Use the Power Units field to choose whether power values are reported as mW or dBm.

Rear Panel

The rear panel provides additional safety and utility functions such as the laser safety interlock and the power monitor output, RS-232, and USB ports. The USB interface is currently used only for firmware upgrades that are made available on Thorlabs website. Future revisions of the firmware will provide for remote control of the instrument's functions.

All units are shipped from Thorlabs with a shorting device that is already installed in the interlock connector, thus allowing the instrument to be operated normally right out of the box. To make use of the interlock feature, a 2.5 mm plug can be wired to the remote interlock switch and plugged into the back-panel interlock jack in place of the shorting plug. Electrical specifications for this function are provided in the manuals, which can be accessed by clicking on the red document icons () below.

Front Panel

MX65E and MX35E Reference Transmitter Front Panel
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Linear Reference Transmitters Front Panel

Back Panel

Reference Transmitter Back Panel
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Linear Reference Transmitter Back Panel
Front Panel of the MX35E and MX65E Series
Callout Description
1 Touchscreen Display and Control
2 Value Adjustment Knob
3 Key Switch and Indicator Light for Internal Laser
4 Earth Ground Port for ESD Wrist Strap Banana Plug
5a Laser Out for Internal Laser Source,
Accepts PM Fiber with FC/PC Connector (Narrow Key)
6a Laser In to Modulator,
Accepts PM Fiber with FC/PC Connector (Narrow Key)
7b Optical Out: Final Output from Modulator
FC/PC Connector (Narrow Key)
8c Amplifier RF In: Signal Input to Amplifier
SMA Female (MX35E)
1.85 mm Female (MX65E)
9 On/Standby Button
  • Uses PM PANDA Fiber for Internal Connection
  • Uses SMF-28-Compatible Fiber for Internal Connection
  • On the MX35E series housing, this connector is located next to the On/Standby button.
Back Panel of all Reference Transmitters
Callout Description
1a I/O Control Port
Outputs from Three Integrated Power Monitors
2 Laser Interlock Jack
3a RS-232 Control Port
4 USB Port (Type B)
5 AC Power Cord Connector
6 Fuse Tray
7 AC Power Switch
  • See the Pin Diagrams tab for pin assignments.

 I/O DB15 Connector

I/O DB15 Connector
The I/O connector provides analog outputs from the three power monitors.
Pin Description Pin Description
1 Power Monitor 1 9 Analog Ground
2 Power Monitor 2 10 Analog Ground
3 Power Monitor 3 11 Reserved for Future Use
4 Reserved for Future Use 12 Reserved for Future Use
5 Analog Ground 13 Monitor 1 Gain Indicator
6 Analog Ground 14 Monitor 2 Gain Indicator
7 Analog Ground 15 Monitor 3 Gain Indicator
8 Analog Ground - -

RS-232 Connector

RS-232 Connector
The RS-232 connector is included to support future remote operation that will be enabled by future firmware upgrades.
Pin Description
1 Not Connected
2 RS232 Input
3 RS232 Output
4 Not Connected
5 Digital Ground
6 Not Connected
7 Not Connected
8 Not Connected
9 Not Connected

USB Type B Connector

USB Type B Connector
The USB connector is provided for firmware upgrades and future remote operation.
High-Speed Reference Transmitter
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Each reference transmitter offers the option to customize the color of the underbody accent lights or turn them off.

Included with Thorlabs' High-Speed Reference Transmitters:

  • Optical Transmitter Main Unit
  • Power Cord According to Local Supply (Determined by Ordering Location, Not Shown)
  • PM Loop-Back Fiber Optic Cable
  • Interlock Keys for Front Panel
  • 2.5 mm Interlock Pin (Pre-installed in Back Panel, Not Shown)
  • 1.25 A, 250 VAC Fuse (Not Shown)
  • USB Type A to Type B Cable, 6' Long (Not Shown)

Software for the Linear Reference Transmitters

Screen Capture of the TLX Laser Remote Control Tool Software V1.6
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The GUI of the Remote Control Software Tool 

Control Our Reference Transmitters Remotely via Serial Commands
Serial commands sent to the MX35E and MX65E series of reference transmitters can control the functionality of the internal laser, RF amplifier, bias controller for the built-in modulator, and variable optical attenuator (VOA), as well as general system parameter settings. The commands can be sent from a computer running any operating system to the RS-232 port on the back panel of the reference transmitter. Computers running Windows® 7, or later versions of the operating system, can send serial commands to the USB port on the back panel of reference transmitter. The touchscreen interface remains active while the reference transmitter is controlled remotely. Descriptions of how to connect a controlling computer to the reference transmitter, the serial command set, and descriptions of each command are included in the Remote Control User Guide.

Application Demonstrating GUI-Based Remote Control of Our Reference Transmitters
The Remote Control Software Tool, which is available for download, is an example graphical user interface (GUI) provided for testing, demonstrating, and exploring the use of the different serial commands. This program is not required to operate the reference transmitter remotely. It opens a connection to the laser source and sends commands in response to buttons clicked by users. Commands sent to the reference transmitter, responses from it, and status information messages are logged to the three rectangular fields located beneath the buttons. Please see the Remote Control User Guide for more information. This program can be used as a basis for the development of custom applications. Please contact us to request the source code.

Software Downloads

Software Version 1.6.1 (September 26, 2017)

Firmware Update Version 1.6.2 (November 15, 2017)

The Remote Control Software Tool and firmware updates are available by clicking on the links below.

Software Download
Software Download

Janis Valdmanis, Ph.D. Optics
Ultrafast Optoelectronics
General Manager

Custom and OEM Options

When your application requirements are not met by our range of catalog products or their variety of user-configurable features, please contact me to discuss how we may serve your custom or OEM needs.  

Request a Demo Unit

Explore the benefits of using a Thorlabs high-speed instrument in your setup and under your test conditions with a demo unit. Contact me for details.

Contact Me

MX40B with cover removed
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 The MX40B Digital Reference Transmitter

Design, Manufacturing, and Testing Capabilities

Thorlabs' Ultrafast Optoelectronics Team designs, develops, and manufactures high-speed components and instrumentation for a variety of photonics applications having frequency responses up to 70 GHz. Our extensive experience in high-speed photonics is supported by core expertise in RF/microwave design, optics, fiber optics, optomechanical design, and mixed-signal electronics. As a division of Thorlabs, a company with deep vertical integration and a portfolio of over 20,000 products, we are able to provide and support a wide selection of equipment and continually expand our offerings.

Our catalog and custom products include a range of integrated fiber-optic transmitters, modulator drivers and controllers, detectors, receivers, pulsed lasers, variable optical attenuators, and a variety of accessories. Beyond these products, we welcome opportunities to design and produce custom and OEM products that fall within our range of capabilities and expertise. Some of our key capabilities are:

  • Detector and Receiver Design, to 70 GHz
  • Fiber-Optic Transmitter Design, to 70 GHz
  • RF & Microwave Design and Simulation
  • Design of Fiber-Optic and Photonics Sub-Assemblies
  • High-Speed Testing, to 70 GHz
  • Micro-Assembly and Wire Bonding
  • Hermetic Sealing of Microwave Modules
  • Fiber Splicing of Assemblies
  • Custom Laser Engraving
  • Qualification Testing

Overview of Custom and Catalog Products  

Our catalog product line includes a range of integrated fiber-optic transmitters, modulator drivers and controllers, detectors, pulsed lasers, and accessories. In addition to these, we offer related items, such as receivers and customized catalog products. The following sections give an overview of our spectrum of custom and catalog products, from fully integrated instruments to component-level modules.  

Fiber-Optic Instruments

To meet a range of requirements, our fiber-optic instruments span a variety of integration levels. Each complete transmitter includes a tunable laser, a modulator with driver amplifier and bias controller, full control of optical output power, and an intuitive touchscreen interface. The tunable lasers, modulator drivers, and modulator bias controllers are also available separately. These instruments have full remote control capability and can be addressed using serial commands sent from a PC.

  • Fiber-Optic Transmitters, to 70 GHz
  • Linear and Digital Transmitters
  • Electrical-to-Optical Converters, to 70 GHz
  • Modulator Drivers
  • Modulator Bias Controllers
  • C- and L-Band Tunable Lasers 

Customization options include internal laser sources, operating wavelength ranges, optical fiber types, and amplifier types.

Fiber-Optic Components

Our component-level, custom and catalog fiber-optic products take advantage of our module design and hermetic sealing capability. Products include detectors with frequency responses up to 50 GHz, and we also specialize in developing fiber-optic receivers, operating up to and beyond 40 GHz, for instrumentation markets. Closely related products include our amplifier modules, which we offer upon request, variable optical attenuators, microwave cables, and cable accessories.

  • Hermetically-Sealed Detectors, to 50 GHz
  • Fiber-Optic Receivers, to 40 GHz
  • Amplifier Modules
  • Electronic Variable Optical Attenuators
  • Microwave Cables and Accessories 

Customization options include single mode and multimode optical fiber options, where applicable, and detectors optimized for time or frequency domain operation.

Free-Space Instruments

Our free-space instruments include detectors with frequency responses around 1 GHz and pulsed lasers. Our pulsed lasers generate variable-width, nanosecond-duration pulses, and a range of models with different wavelengths and optical output powers are offered. User-adjustable repetition rates and trigger in/out signals provide additional flexibility, and electronic delay-line products enable experimental synchronization of multiple lasers. We can also adapt our pulsed laser catalog offerings to provide gain-switching capability for the generation of pulses in the 100 ps range.

  • Pulsed Lasers with Fixed 10 ns Pulse Duration
  • Pulsed Lasers with Variable Pulse Width and Repetition Rates
  • Electronic Delay Units to Synchronize NPL Series Pulsed Lasers
  • Amplified Detectors

Customization options for the pulsed lasers include emission wavelength, optical output powers, and sub-nanosecond pulse widths.

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Transmitter Instruments and Tunable Lasers
Item # Speed Internal Laser Internal Modulator
RF Amplifier
Variable Optical
Attenuator (VOA)
Automatic Bias Controller
MBX N/A - - - yes yes
Tunable Telecom-Grade Laser Sources
TLX1 N/A C-Band, Tunable - - - yes
TLX2 N/A L-Band, Tunable
High-Speed Modulator Drivers
MX10A 12.5 Gb/sa - - Digital yes yes
MX40A 40 Gb/sa
High-Speed Optical Transmitters
MX10B 12.5 Gb/sa C-Band, Tunable Intensity Digital yes yes
MX10B-LB 12.5 Gb/sa L-Band, Tunable
MX10B-1310 12.5 Gb/sa 1310 nm, Fixed
MX10C 12.5 Gb/sa C-Band, Tunable Phase Digital - yes
MX10C-LB 12.5 Gb/sa L-Band, Tunable
MX10C-1310 12.5 Gb/sa 1310 nm, Fixed
MX35E 35 GHzb C-Band, Tunable Intensity Linear yes yes
MX35E-LB 35 GHzb L-Band, Tunable
MX35E-1310 35 GHzb 1310 nm, Fixed
MX40B 40 Gb/sa C-Band, Tunable Intensity Digital yes yes info
MX40B-LB 40 Gb/sa L-Band, Tunable
MX40B-1310 40 Gb/sa 1310 nm, Fixed
MX40C 40 Gb/sa C-Band, Tunable Phase Digital - yes
MX40C-LB 40 Gb/sa L-Band, Tunable
MX40C-1310 40 Gb/sa 1310 nm, Fixed
MX65E 65 GHzb C-Band, Tunable Intensity Linear yes yes
MX65E-LB 65 GHzb L-Band, Tunable
MX65E-1310 65 GHzb 1310 nm, Fixed
E-O Converters for VNA Applications
MX40G 40 GHzb C-Band, Tunable Intensity - yes yes
MX40G-LB 40 GHzb L-Band, Tunable
MX40G-1310 40 GHzb 1310 nm, Fixed
MX70G 70 GHzb C-Band, Tunable Intensity - yes yes
MX70G-LB 70 GHzb L-Band, Tunable
MX70G-1310 70 GHzb 1310 nm, Fixed
  • Maximum Supported Digital Bit Rate
  • Maximum Analog Bandwidth

Selection Guide for Transmitter Instruments

The capabilities of Thorlabs' extensive range of transmitter instruments are summarized in the text and table below. All members of this product series share a similar interface, as well as a common remote control command set.

Automatic Bias Controller
Thorlabs' fully-featured automatic bias controller provides complete and precise control of DC bias and optical output power for any fiber-coupled LiNbO3 EO intensity modulator, regardless of signal speed. Automatic bias controllers are ideal for use within a customized setup that uses an external laser, intensity modulator, signal source, and RF amplifier.

Tunable Telecom-Grade Laser Sources
Emitting in the C-band or the L-band, these lasers have narrow typical linewidths of 10 kHz. A frequency dither option aids in stabilizing the laser wavelength, and the integrated variable optical attenuator (VOA) provides optical output power control. These lasers are tunable in 50 GHz steps across the ITU frequency grid, and feature a 1 MHz step size fine-tune capability, as well.

High-Speed Modulator Drivers
With an operational wavelength range of 1250 nm to 1610 nm, each modulator driver provides control for an external fiber-coupled LiNbO3 EO modulator. Each modulator driver includes an RF amplifier with amplitude and eye-crossing controls and accepts an external drive signal source. Models with integrated automatic bias controllers are offered for use with intensity EO modulators.

High-Speed Optical Transmitters
Designed to provide fully-integrated solutions for high-speed light modulation, these systems are built around a LiNbO3 intensity or phase modulator. The MX10B, MX40B, MX10C, and MX40C series of systems include a digital (limiting) RF amplifier, which offers fixed gain and an adjustable output voltage swing. The MX35E and MX65E series include a high-bandwidth linear (analog) RF amplifier with adjustable gain, making it well suited for pulse amplitude modulation and related applications.

E-O Converters for VNA Applications
With our MX40G and MX70G series of E-O converters, any E-E vector network analyzer can be used to perform optical testing up to 40 GHz or 70 GHz respectively. The E-O converter is a fully-integrated solution that includes a laser, a modulator, and bias control.

35 GHz Linear Reference Transmitters

Key System Specificationsa
Item # MX35E MX35E-LB MX35E-1310
Bandwidth (Maximum) 35 GHz (-3 dB)
Internal Laser Typeb C-Band, Tunable L-Band, Tunable Fixed Wavelength
Internal Laser Wavelengthb 1527.6 - 1565.5 nm 1570.0 - 1608.8 nm 1310 nm
RF Amplifier Gain 10 dB to 23 dB (User-Adjustable)
Small Signal Bandwidth 35 GHz
Low Frequency Cutoff 200 kHz
  • For complete specifications, see the manual.
  • An 850 nm fixed-wavelength laser is also available upon request. Please contact Tech Support for details.
  • 35 GHz Analog Bandwidth
  • User-Adjustable RF Amplifier Gain
  • Integrated Internal Laser Options:
    • C-Band Laser Tunable on ITU 50 GHz Grid
    • L-Band Laser Tunable on ITU 50 GHz Grid
    • 1310 nm Fixed-Wavelength Laser
    • Contact Tech Support for Integrated 850 nm Laser

The transmitters are designed for linear applications that require frequency response up to 35 GHz, which makes them compatible with high bit-rate modulation schemes that rely on multi-level encoding, such as PAM4.

The RF amplifier has user-adjustable gain from 10 dB to 23 dB, which changes the slope of output versus input voltage curves. The adjustable gain control allows the output of the amplifier to remain linear across a broad range of input signal levels.

Please note: The MX35E-LB and MX35E-1310 transmitters will ship from the US within 7 to 10 days of placing an order if all component parts are available.
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
MX35E Support Documentation
MX35E35 GHz Max Linear Reference Transmitter, C-Band Laser, Linear Amplifier
MX35E-LB Support Documentation
MX35E-LB35 GHz Max Linear Reference Transmitter, L-Band Laser, Linear Amplifier
Lead Time
MX35E-1310 Support Documentation
MX35E-131035 GHz Max Linear Reference Transmitter, 1310 nm Laser, Linear Amplifier
Lead Time

65 GHz Linear Reference Transmitters

Key System Specificationsa
Item # MX65E MX65E-LB MX65E-1310
Bandwidth (Maximum) 65 GHz (-6 dB)
Internal Laser Type C-Band, Tunable L-Band, Tunable Fixed Wavelength
Internal Laser Wavelength 1527.6 - 1565.5 nm 1570.0 - 1608.8 nm 1310 nm
RF Amplifier Gain 11 dB
Small Signal Bandwidth 65 GHz
Low Frequency Cutoff 70 kHz
  • For complete specifications, see the manual.
  • 65 GHz Analog Bandwidth
  • Designed for 56 Gbaud/s Applications
  • Integrated Internal Laser Options:
    • C-Band Laser Tunable on ITU 50 GHz Grid
    • L-Band Laser Tunable on ITU 50 GHz Grid
    • 1310 nm Fixed-Wavelength Laser

These transmitters have a usable bandwidth of 65 GHz, which makes them compatible with high bit-rate modulation schemes that rely on multi-level encoding, such as PAM4. The system has a smooth response over its entire frequency range (see the graph on the Specs tab). The RF amplifier has a fixed gain of 11 dB.

Please note: The MX65E and MX65E-LB transmitters will ship from the US within 7 to 10 days of placing an order if all component parts are available.
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
MX65E Support Documentation
MX65ENEW!65 GHz Max Linear Reference Transmitter, C-Band Laser, Linear Amplifier
Lead Time
MX65E-LB Support Documentation
MX65E-LBNEW!65 GHz Max Linear Reference Transmitter, L-Band Laser, Linear Amplifier
Lead Time
MX65E-1310 Support Documentation
MX65E-1310NEW!65 GHz Max Linear Reference Transmitter, 1310 nm Laser, Linear Amplifier
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