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Fiber-Coupled, Benchtop Tunable Laser Sources

  • General Purpose Telecom Tunable Lasers for C-Band or L-Band
  • +13 dBm Laser, 10 kHz Linewidth, Low Noise
  • Built-In Variable Optical Attenuator for Power Control
  • Dither Function Stabilizes Wavelength


Tunable Laser Source,

Touchscreen Interface

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Block Diagram for TLX Tunable Lasers
Click to Enlarge

Block Diagram of the TLX Series Tunable Lasers. See the Operation tab for details.
*Monitor 1 is for internal use within the laser's control loop only.

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

We Design, Develop, and Manufacture
Equipment up to 70 GHz


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Custom or OEM Applications?

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  • Telecom Lasers Tunable on ITU 50 GHz Frequency Grid
    • TLX1: 1528 - 1566 nm (C-Band)
    • TLX2: 1570 - 1609 nm (L-Band)
  • Narrow 10 kHz Linewidth
  • +13 dBm Output Power and Low Noise Operation
  • Built-In Variable Optical Attenuator (VOA) for Automatic or Manual Power Control
  • Frequency Dither Option Aids in Wavelength Stabilization
  • Temperature-Controlled External Cavity Laser with Isolator
  • Full PM Fiber Optical Path
  • Control via Intuitive Touchscreen Interface or Remotely using USB or RS-232 Connections

These Tunable Laser Sources emit light that can be swept over commonly used telecommunication wavelength ranges. They are used in the research and design of wavelength division multiplexers (WDMs) and related components, during manufacturing testing, and in the implementation of full optical links. The TLX1 emits in the C-band, while the TLX2 emits in the L-band. The optical output has a narrow typical linewidth of 10 kHz, and operation with the frequency dither option stabilizes the laser wavelength. The wavelength tuning resolution is 50 GHz. Complete control over the optical output power is provided by the built-in variable optical attenuator, which can operate in Constant Attenuation or Constant Power modes. For complete specifications, see the Specs tab. 

The optical fiber path from the internal laser module through the optical output port is fully polarization maintaining (PM), and all external optical connections are made using FC/PC connectors. As shown in the above diagram, emission from the internal laser is coupled to the Laser Out port. The user has the option to couple this emission to the VOA In port via the supplied PM loop-back cable, or the user may alternatively couple an external laser to the VOA. Laser light input to the VOA In port should have a maximum input power of 20 dBm (100 mW), and the light should be linearly polarized along the slow axis (aligned to the connector key). See the Front & Back Panels tab for details on the input and output ports.

These laser sources 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.  

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
C-Band Laser Noise Spectrum
Click to Enlarge

FM Noise Spectrum of the tunable laser. The dither function helps stabilize the wavelength. Turning the dither off provides lower noise.
Laser Tuning
Item # TLX1 TLX2
Tunable Wavelength Range 1528 - 1566 nm 1570 - 1609 nm
Tunable Frequency Range 191.50 - 196.25 THz 186.35 - 190.95 THz
Laser Specifications
Parameter Unit Min Typ Max
Optical Output Power dBm 12.5 13.5 14.5
Frequency Accuracy GHz -1.5 - 1.5
Tuning Resolution GHz - 50 -
Tuning Speed (Between Wavelengths) s - 10 -
Side Mode Suppression Ratio dB 40 55 -
Optical Signal Noise Ratio dB 40 60 -
Intrinsic Linewidth kHz - 10 15
Relative Intensity Noise dB/Hz - - -145
Back Reflection dB - - -14
Polarization Extinction Ratio dB 18 - -
VOA Specifications
Optical Input Power 20 dBm (Max)a
External Laser Wavelength Range 1525 nm - 1610 nm
Optical Insertion Lossb 0.7 dB (Typ)
Power Monitors Accuracyc ±0.5 dBm
Power Monitors Resolution 0.01 dBm
VOA Response Time ≤1 s
  • 22 dBm Absolute Max
  • VOA In to VOA Out
  • At 1550 nm
Housing Specifications
Outer Dimensions (W x D x H)a 250.0 mm x 300.0 mm x 122.0 mm
(9.84" x 11.81" x 4.80")
Internal Fiber PM Panda-Style Fiber
Input/Output Port Fiber Connectors FC/PCb
  • For detailed dimensions, see the mechanical drawing by clicking on the red Docs icon () below.
  • See the Front & Back Panels tab for more details on the input and output ports.

Internal Setup

The block diagram below provides a basic illustration of the internal setup of the tunable lasers. The internal laser is routed via the loop-back cable on the front panel and input to the variable optical attenuator (VOA). Alternatively, the user can connect an external laser to the VOA input port. After the laser passes through the VOA, it exits through the optical output port on the front panel. The rear panel features ports for several additional monitor and control functions.

Block Diagram of TLX Series Tunable Lasers
Block Diagram of the Internal Setup of the Tunable Lasers.
*Monitor 1 is for internal use within the laser's control loop only.
Home Screen of the TLX1 and TLX2
Click to Enlarge

Main Menu (Home Screen) of the TLX1 and TLX2

Touchscreen Interface

These devices can be fully controlled by using the resistive touchscreen display for all functions. Either a finger or plastic stylus can be used to make selections on the screen. Additionally, 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.

The home screen is organized in three main sections.

  • Left Column: Buttons to turn each instrument function on or off.
  • Middle Column: Reports the current operating parameters of each instrument function. Tap in this column to go to the Settings page for each function.
  • Right Column: Buttons that provide access to various utility and help functions (e.g., control of audio and visual features).

The basic layout can be seen in the screenshots to the right.

Laser Settings Screen of the TLX1 and TLX2
Click to Enlarge

Laser Settings Screen

Laser Settings
From this screen, the user can tune the laser's output wavelength (see the Specs tab for the frequency and wavelength ranges of each device). The laser settings page also allows the user to set the dither function to aid in stabilizing the wavelength. Turning the dither off will result in lower phase and intensity noise; however, the wavelength may drift slightly over time.The noise performance of the laser with and without dither can be seen on the Specs tab. The laser settings screen also provides a readout of many of the laser operating parameters.

VOA Settings Screen of the TLX1 and TLX2
Click to Enlarge

VOA Settings Screen

VOA Settings
On this screen, the user can control the optical output power via the Variable Optical Attenuator (VOA). The VOA can be operated in one of two modes: Constant Attenuation or Constant Output Power. In Constant Attenuation mode, the attenuation level between the output of the laser and the output of the VOA remains fixed, allowing power changes at the input 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.

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 the 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. The electrical specifications for that function can be found in the manual (PDF link).

Front Panel

Front Panel of the TLX1 and TLX2
Click to Enlarge

TLX1 Front Panel
Callout Description
1 Touchscreen Display and Control
2 Value Adjustment Knob
3 Key Switch and Indicator Light for Internal Laser
4a Laser Output,
Accepts PM Fiber with FC/PC Connector
5a VOA Input (External Laser Input),
Accepts PM Fiber with FC/PC Connector
6a VOA Output,
Accepts PM Fiber with FC/PC Connector
7 On/Standby Button
  • Uses PM Panda Fiber for Internal Connection

Back Panel

Back Panel of the TLX1 and TLX2
Click to Enlarge

TLX1 Back Panel
Callout Description
1a I/O Control Port
Outputs from Two 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 (Female)

The I/O connector provides analog outputs from the two power monitors.

Pin Description Pin Description
1 Reserved for Future Use 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 Reserved for Future Use
6 Analog Ground 14 Monitor 2 Gain Indicator
7 Analog Ground 15 Monitor 3 Gain Indicator
8 Analog Ground - -

RS-232 Connector (Male)

The RS-232 connector is provided for firmware upgrades and will support remote operation in the future.

Pin Description
1 Not Connected
2 RS-232 Input
3 RS-232 Output
4 Not Connected
5 Digital Ground
6 Not Connected
7 Not Connected
8 Not Connected
9 Not Connected

USB, Type B (Female)

The USB connector is provided for firmware upgrades and will support remote operation in the future.

Each Tunable Laser Source includes:

  • Laser Source Main Unit
  • Power Cord According to Local Supply (Determined by Ordering Location)
  • PM Loop-Back Fiber Optic Cable
  • Interlock Keys for Front Panel
  • 2.5 mm Interlock Pin (Pre-installed in Back Panel)
  • 1.25 A, 250 VAC Fuse
  • USB Type A to Type B Cable, 6' Long
Screen Capture of the TLX Laser Remote Control Tool Software V1.6
Click to Enlarge

The GUI of the Remote Control Software Tool 

Software for the TLX1 and TLX2 Tunable Laser Sources 

Control the TLX Series Lasers Remotely via Serial Commands
Serial commands sent to the TLX1 or TLX2 can control the functionality of internal laser module and variable optical attenuator (VOA), as well as set general system parameters. The commands can be sent from a computer running any operating system to the RS-232 port on the back panel of the TLX series laser. 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 TLX series laser. The touchscreen interface remains active while the laser is controlled remotely. Descriptions of how to connect a controlling computer to the TLX series laser, the serial command set, and descriptions of each command are included in the Remote Control User Guide.

Application Demonstrating GUI-Based Remote Control of the TLX1 and TLX2
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 TLX1 or TLX2 remotely. It opens a connection to the laser source and sends commands in response to buttons clicked by users. Commands sent to the TLX series laser, 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 1.6.1 (September 26, 2017)

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

Software Download

Firmware Update

Version 1.6.2 (November 15, 2017)

Click on the link below to download the latest firmware.

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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+1 Qty Docs Part Number - Universal Price Available / Ships
TLX1 Support Documentation
TLX1Benchtop Tunable Laser Source, C-Band
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TLX2 Support Documentation
TLX2Benchtop Tunable Laser Source, L-Band
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