Automatic Bias Controllers for Lithium Niobate (LiNbO3) Modulators

  • Quadrature, Peak, and Null Automated Modes
  • Ditherless and Constant Bias Modes
  • Built-In VOA for Power Control
  • Models for 770 – 980 nm or 1250 – 1610 nm

Touchscreen interface shown with external laser source
and fiber-coupled EO modulator connected to the bias controller.


Bias and Power Controller for External Modulators,
770 - 980 nm Wavelength Range

Related Items

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MBX Bias Controller Block Diagram
Click to Enlarge

Block Diagram of the Internal Setup of MBX Series Modulator Bias Controllers
See the Operation tab for details.

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

If you are not sure whether our catalog items meet your needs, we invite you to contact us. Or ask about a loan, so you can try them out for yourself, in your own lab. We can also support custom or OEM requirements you may have.

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  • Designed for Fiber-Coupled LiNbO3 Intensity Modulators
  • Two Versions for Different Wavelength Ranges:
    • MBX2 Controller: 770 - 980 nm
    • MBX Controller: 1250 - 1610 nm
  • Fully Automated or Fixed-Voltage Bias Control for Intensity Modulators
    • Dithered Operation in Automated Quadrature, Peak, and Null Set Point Modes
    • Ditherless Operation in Automated Constant Ratio Mode
    • Ditherless Operation in Fixed-Voltage (Constant Bias) Mode
  • Built-In Variable Optical Attenuator (VOA) for Automatic or Manual Power Control
  • Three Calibration Wavelengths:
    • MBX2 Controller: 785 nm, 852 nm, and 940 nm
    • MBX Controller: 1310 nm, 1550 nm, and 1590 nm
  • Control via Intuitive Touchscreen Interface or Remotely using USB or RS-232 Connections

Thorlabs' MBX Series Bias Controllers provide complete and precise control of DC bias and optical output power for fiber-coupled lithium niobate (LiNbO3) electro-optic intensity modulators, regardless of signal speed. The operational wavelength range of the MBX2 controller extends from 770 nm to 980 nm and the user may select from power calibration points at 785 nm, 852 nm, and 940 nm. The operational wavelength range of the MBX controller extends from 1250 nm to 1610 nm (O- through L-band) and the user may select from power calibration points at 1310 nm, 1550 nm, and 1590 nm. Whether operated in an R&D laboratory or manufacturing environment, these fully-featured modulator bias controllers are ideal for use within a customized setup that uses an external laser, LiNbO3 intensity modulator, signal source, and RF amplifier.

Several operation modes are provided. Automated bias control operation continuously adjusts the DC bias voltage to maintain the correct set point, and there are dithered and ditherless options. When operating in a dithered control mode, an adjustable dither tone with a user-selectable frequency between 1 and 10 kHz is used as a pilot tone. Each automated dithered mode biases the modulator at a different operating point (Peak, Null, or Quadrature); all operating points are referenced to the modulator transmission function described in the Operation tab. If the application requires automated, but ditherless, bias control of the modulator, Constant Ratio mode may be chosen. It is also possible to operate each controller in the fixed-voltage and ditherless Constant Bias mode, in which a user-selected DC bias voltage is applied to the modulator. This mode can be useful for brief measurements, but its inability to track modulator drift renders it impractical for measurements longer than a few minutes.

MBX series controllers 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 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.

Closely Related Items
These controllers are part of a range of fiber-coupled LiNbO3 electro-optic modulator driver and control instruments developed by Thorlabs to meet a variety of application requirements. The key features of each instrument in the range are listed in the Selection Guide tab above. Please contact the Ultrafast Optoelectronics Team if your application requires a driver or controller with additional customization. We also offer a full range of LiNbO3 modulators for use with these instruments.

General System Specificationsa
Item # MBX2 MBX
Optical Input Power
(from External Laser)
20 dBm (Maximum)
22 dBm (Absolute Maximum)
Wavelength Range 770 - 980 nm 1250 - 1610 nm
Power Calibration Points 785 nm, 852 nm, and 940 nm 1310 nm, 1550 nm, and 1590 nm
Bias Voltage Range ±10 V
Bias Modes Quadrature (Positive and Negative Slope)
Manual (Constant Ratio and Constant Bias)
Dither Frequency Rangeb 1 to 10 kHz
Dither Amplitude Rangeb 20 mV to 2 V
Internal Optical Fiber PM780-HP PM Ports: PM1300-XP
SM Ports: SMF-28c
Internal Controld
Power Monitor Accuracye ±0.5 dBm
Power Monitor Resolutione 0.01 dBm
Power Monitor Insertion Lossf 0.15 dB 0.1 dB
VOA Insertion Loss 0.75 dB 0.4 dB
VOA Response Time 1 s
Fiber Connectors FC/APC, 2.0 mm Narrow Key FC/PC, 2.0 mm Narrow Key
Bias Out SMA Female
RS-232 DB9
Dimensions 322.3 mm x 250.0 mm x 134.8 mm
(12.69" x 9.84" x 5.31")
Weight 3.8 kg (8.4 lbs)
  • All values are typical unless noted otherwise.
  • Adjustable
  • Laser Input and Output to Modulator ports are PM fiber; Return from Modulator and Final Output are SM fiber.
  • Specified at the Calibration Wavelengths
  • Applies to all three internal monitors.
  • Per Monitor
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
MBX Series Bias Controller Block Diagram
Click to Enlarge

Block Diagram of the Internal Setup of MBX Series Modulator Bias Controllers
See the Operation tab for details.

System Overview

The block diagram shown to the right illustrates the internal setup of MBX series modulator bias controllers. The fiber-coupled light path is traced by the red arrows, and the blue arrows show the electrical connections. The optical laser power is coupled to the Laser Input port and read by Monitor 1 before exiting to the external modulator. The optical output of the modulator is coupled to the Return from Modulator port and routed through the variable optical attenuator (VOA)-based power control system before exiting as the Final Optical Output. Automatic and Manual bias control is performed by referencing intensity readings from Monitor 1 and Monitor 2, and the power controller uses intensity readings from Monitor 2 and Monitor 3 to control and stabilize the output optical power. The rear panel features output ports for several additional monitor and control functions.

Modulator Bias Controller System Wavelength Settings Screen
Click to Enlarge

Figure 2: System Wavelength Selection Screen
Bias Controller Main Menu
Click to Enlarge

Figure 1: Home Screen
Modulator Bias Controller Dither Settings Screen
Click to Enlarge

Figure 3: Bias Controller Settings Screen to Adjust Dither
Modulator Bias Controller Modulator Operating Mode Settings Screen
Click to Enlarge

Figure 4: Bias Controller Settings Screen to Adjust
Operating Mode
Modulator Bias Controller LiNbO3 EO Modulator Transmission Function
Click to Enlarge

Figure 5: Bias Points for an Intensity Modulator
Vπ is the half-wave voltage.
Modulator Bias Controller Variable Optical Attenuator Settings Screen
Click to Enlarge

Figure 6: VOA Settings Screen to Adjust Output Power

Instrument Control

The graphical user interface (GUI) gives the user complete control over all instrument functionality. Each modulator controller uses 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 to quickly change setpoint values. Pressing (clicking) the knob will confirm a new setpoint value. Additionally, the instruments can be driven using serial commands delivered via connectors on the rear panel. This is described in the remote control user guide, and a Windows program that demonstrates remote control of the converter is available in the Software tab.

The home screen of the controller, shown in Figure 1, is organized into three main sections. 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.

  • 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.

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

System Wavelength Settings

The system wavelength may be selected on the Menu page, which is shown in Figure 2. The choice of system wavelength specifies which calibration settings to apply to the intensity monitors in the controller. Change the power monitor calibration wavelength to the value closest to the wavelength of the laser source being used.

The MBX modulator controller 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 MBX2 controller can be used at wavelengths anywhere between 780 nm and 980 nm and calibration settings are supplied for 785 nm, 852 nm, and 940 nm.

Modulator Bias Controller

The bias controller and VOA settings can be adjusted using pages accessed by touching the center region of the Home page. A setting screen for the Quadrature mode of the bias controller is shown in Figure 3. The parameters written in white font are modified using the function buttons, which are customized for each parameter and stacked in the column to the right of the screen. The parameters in orange font may be monitored here, but not set. Toggle Dither on and off by tapping its value in the center column of the screen. Dither is discussed in more detail in the following section. In this screen shot, Dither Amplitude is selected and its set point value can be adjusted by tapping the arrows on the right of the touchscreen. Tap the check mark to confirm a value, and the X to cancel any changes. Set point values may also be quickly changed by dialing the knob on the front panel of the housing. Pressing (clicking) the knob will confirm a new set point value.

Bias Settings
The Bias Settings screens allow the operator to select among and customize the different operating modes, which are chosen by touching the Mode value and then navigating using the function buttons on the right of the screen. Figure 4 shows these function buttons, which are labeled PEAK, QUAD, NULL, and MAN.

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 5. 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, MBX series controllers include the Constant Ratio mode. It is enabled by tapping the MAN function on the right of the screen shown in Figure 4 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. The controller allows a fixed bias voltage to be 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

The VOA provides the means for adjusting and stabilizing the modulated optical output power. The VOA settings screen, which is shown in Figure 6, 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 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 utility functions such as the power monitor output, RS-232, and USB ports. Both the USB and RS-232 interfaces can be used for remote control operation of the modulator bias and power controller. The serial commands and control features available are fully described in the remote control user guide. The USB interface is also used for installing firmware upgrades as they become available.

MBX Series Modulator Bias Controller Front Panel
Click to Enlarge

MBX Series Modulator Bias Controller Front Panel
Screenshot taken with external laser source and fiber-coupled EO modulator connected.
Callout Description
1 Touchscreen Display and Control
2 Value Adjustment Knob
3 Laser Input to Bias Controller
MBX2 Accepts PM Fiber with FC/APC Connectora
MBX Accepts PM Fiber with FC/PC Connectorb
4 Laser Output to Modulator Input
MBX2 Accepts PM Fiber with FC/APC Connectora
MBX Accepts PM Fiber with FC/PC Connectorb
5 Return from Modulator Output to Power Controller
MBX2 Accepts PM Fiber with FC/APC Connectora
MBX FC/PC Connectorc
6 Optical Output: Final Optical Output
MBX2 Accepts PM Fiber with FC/APC Connectora
MBX FC/PC Connectorc
7 Bias Output to Modulator Input, SMA Female
8 On/Standby Button
  • Uses PM780-HP Fiber for Internal Connection
  • Uses PM1300-XP Fiber for Internal Connection
  • Uses SMF-28 Fiber for Internal Connection
MBX Series Modulator Bias Controller Back Panel
Click to Enlarge

MBX Series Modulator Bias Controller Back Panel
Callout Description
1a I/O Control Port, Female HD-DB15 Connector
Outputs from Three Integrated Power Monitors
2a RS-232 Control Port, Male DB9 Connector
3 USB Port (Type B)
4 AC Power Cord Connector
5 Fuse Tray
6 AC Power Switch
  • See the Pin Diagrams tab for pin assignments.

 I/O HD-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 Power Monitor 1 Gain Indicator
6 Analog Ground 14 Power Monitor 2 Gain Indicator
7 Analog Ground 15 Power Monitor 3 Gain Indicator
8 Analog Ground - -

RS-232 DB9 Connector

The RS-232 DB9 connector is included to support remote operation.
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
The USB connector is provided for firmware upgrades and remote operation.

Each Modulator Bias Controller Includes:

  • Modulator Bias Controller Main Unit
  • Region-Specific Power Cord (Determined by Ordering Location)
  • 1.25 A, 250 VAC Fuse
  • USB Type A to Type B Cable, 6' Long
Screen Capture of the Remote Control Tool Software
Click to Enlarge

The GUI of the Remote Control Software Tool

Software for MBX Series Automated Bias Controllers

Control the Bias Controller Remotely via Serial Commands
Serial commands sent to the bias controller can control the functionality of the internal EO modulator bias controller 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 controller. Computers running Windows® 7, or later versions of the operating system, can send serial commands to the USB port on the back panel of the controller. The touchscreen interface remains active while the controller is controlled remotely. Descriptions of how to connect a controlling computer to the controller, the serial command set, and descriptions of each command are included in the Remote Control User Guide.

Application Demonstrating GUI-Based Remote Control of MBX Series Bias Controllers
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 controller remotely. It opens a connection to the controller and sends commands in response to buttons clicked by users. Commands sent to the controller, 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.


Version 1.8.8 (March 26, 2024)

Click on the link below to download the Remote Control Software Tool.

Software Download

Firmware Update

MBX2 - Version 2.1.0 (March 26, 2024)
MBX - Version 1.8.3
(January 13, 2020)

Click on the link below to download the latest firmware.

Firmware 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
Click to Enlarge

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 110 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 110 GHz
  • RF & Microwave Design and Simulation
  • Design of Fiber-Optic and Photonics Sub-Assemblies
  • High-Speed Testing, to 110 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 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 110 GHz
  • Linear and Digital Transmitters
  • Electrical-to-Optical Converters, to 110 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.

Posted Comments:
user  (posted 2021-08-20 17:51:59.73)
We are conducting a two-tone IMD test with an EO modulator using the MBX. When increasing the power of the input tones at f1 and f2 monotonically, the power of the output tones go up and down randomly. We believe the MBX is trying to maintain quad bias as the input power is changing. One possible solution we're thinking about is using the MBX to set the DC bias before starting the measurements, then take the MBX offline while conducting the measurements. Should the MBX be able to keep track of the bias changes due to the RF signals?
YLohia  (posted 2021-09-01 10:45:56.0)
Thank you for contacting Thorlabs. It certainly appears that the MBX is trying to maintain the set point while the input is changing. What's not clear is if the tones are riding on some CW level. The MBX monitors average power, so if the ratio of average power to the tone changes then the final output will be affected by that. We have reached out to you directly to troubleshoot further.

Choose Optical Transmitter by Application

  1. Beginning at the left side of the table, choose your desired system characteristics.
  2. Follow the table to the right and continue to select characteristics from the options within the same row as your previous selection.
  3. After reaching a Base Item #, choose a laser type. Your system's item # will be your base item # combined with the suffix for your laser type, e.g. MX40B-1310.
Start Here Follow the Table to the Right and Choose From These Options Find Your System Here
Modulator Type Primary Application Modulation Format Speed RF Input Base Item # Item # Suffix:
Laser Type
Amplitude Time Domain / Eye Diagram Linear / 4-Level PAM4 32 GBaud Differential MX35D No Suffix:
C-Band Tunable Laser

L-Band Tunable Laser

1310 nm Fixed Laser

850 nm Fixed Lasera,b
Single Ended MX35E
56 GBaud MX65E
Digital / 2-Level NRZ / OOK 10 Gbps MX10B
40 Gbps MX40B
56 Gbps MX50E
56 Gbps MX65E
Frequency Domain / VNA 40 GHz MX40G
70 GHz MX70G
110 GHz MX110G
Phase 10 Gbps MX10C
40 Gbps MX40C
  • The 850 nm fixed laser is not available for the following base item #s:
    • MX10C
    • MX40C
    • MX65E
    • MX70G
    • MX110G
  • The MX40G-850 transmitter is available through the website. For other systems with an 850 nm fixed laser, excluding those listed in footnote a, please contact Tech Support.

Choose Optical Transmitter Instrument by Features

Transmitter Instruments and Tunable Lasers
Item # Speed Internal Laser Internal Modulator
RF Amplifier
Variable Optical
Attenuator (VOA)
Automatic Bias Controller
(770 - 980 nm)
N/A - - - yes yes
(1250 - 1610 nm)
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
(1250 - 1610 nm)
12.5 Gb/sa - - Digital yes yes
(1250 - 1610 nm)
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
MX35D 35 GHzb C-Band, Tunable Intensity Linear with
yes yes
MX35D-LB 35 GHzb L-Band, Tunable
MX35D-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
MX50E-850 50 GHzb 852 nm, Fixed Intensity Linear yes yes
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-850 40 GHzb 850 nm, Fixed
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
MX70G-DB1 70 GHzb C-Band, Tunable Intensity - yes yes
1310 nm, Fixed
MX110G 110 GHzb C-Band, Tunable Intensity - yes yes
MX110G-1310 110 GHzb 1310 nm, Fixed
  • Maximum Supported Digital Bit Rate
  • Maximum Analog Bandwidth

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, MX50E, and MX65E series include a high-bandwidth linear (analog) RF amplifier, making it well suited for pulse amplitude modulation and related applications.

E-O Converters for VNA Applications
With our MX40G, MX70G, and MX110G series of E-O converters, any E-E vector network analyzer can be used to perform optical testing up to 40 GHz, 70 GHz, and 110 GHz respectively. The E-O converter is a fully-integrated solution that includes a laser, a modulator, and bias control.

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Modulator Bias and Power Controllers

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
MBX2 Support Documentation
MBX2Modulator Bias and Power Controller, 770 - 980 nm Wavelength Range
MBX Support Documentation
MBXModulator Bias and Power Controller, 1250 - 1610 nm Wavelength Range