Thulium-Doped Fiber Lasers

Features

• CW Lasers in the Thulium Emission Band
  • 1900 nm, 1950 nm, or 2000 nm Emission Wavelengths Available from Stock
  • Custom Versions Available at Discrete Wavelengths from 1800 to 2050 nm
• Fiber-Bragg-Grating (FBG)-Stabilized ≤0.2 nm RMS Linewidth
• Adjustable Output Power
• Intuitive Turnkey Operation Through Panel Interface or Remote USB Commands
• Single Mode Fiber Output
• FC/APC Bulkhead

Thorlabs' Thulium-Doped (Tm) Fiber Lasers are benchtop Fabry-Perot fiber laser sources featuring single mode fiber output in the 2 µm band and simple operation for test and measurement applications. Each fiber laser is constructed using a thulium-doped fiber as the gain medium and two fiber Bragg gratings to select the laser wavelength. In contrast to Fabry-Perot semiconductor lasers, the FBG-based Fabry-Perot fiber laser design has narrow-bandwidth FBG reflectors and smaller longitudinal mode spacing (typically <200 MHz compared to >100 GHz for semiconductor lasers). This enables the RMS spectrum to be much narrower (≤0.2 nm versus a few nm) with both short-term and long-term spectral stability. These features make the Tm-doped fiber lasers ideal for applications where spectral stability or narrow spectral width is required.

Three wavelength options are available from stock: 1900 nm, 1950 nm, and 2000 nm. Tm-doped fiber can also support other emission wavelengths from 1800 nm to 2050 nm. Custom fiber lasers with different emission wavelengths are available upon request by contacting Tech Support. The graph below shows the typical output power for a sample of possible custom emission wavelengths.

The laser output is accessible via a fiber connector bulkhead that is compatible with 2.0 mm narrow key FC/APC connectors. An integrated isolator at the output minimizes the impact of back reflections on the laser cavity. For best results, use a fiber patch cable with SM2000 fiber (e.g., Item # P3-2000-FC-2) to connect the output of the laser source to other fiber-coupled devices or free-space optics.

An LCD display allows the user to view the parameters for the fiber laser. The user can adjust the drive current of the pump laser to control the fiber laser output power; each laser is shipped with test data that shows output power scaling as a function of the pump drive current. A USB interface allows control of the laser source through a command line interface. Please see the Software tab for Windows drivers. Each laser source also includes a universal power supply rated for 100 to 240 VAC without the need for selecting the voltage.

For added safety, there is an interlock located on the rear panel that must be shorted in order for the output to be enabled. This can easily be configured to be triggered by lab doors to disable the fiber laser in unsafe conditions. The power switch is a key-lock system to prevent accidental or unwanted use. An enable button must be set to activate the unit with a green LED indicator to easily determine its current state. There is a 3-second delay before the fiber laser turns on, and the user is warned by the rapidly blinking LED.

Custom Fiber Lasers

Thorlabs can produce custom fiber lasers with any emission wavelength from 1800 nm to 2050 nm with a ≤0.2 nm RMS linewidth. Thulium-doped fiber lasers use fiber Bragg gratings for wavelength selection. Please contact Tech Support for details.

Click to Enlarge
This example spectrum shows the narrow linewidth produced by the double FBG design of these Tm-doped fiber lasers. For more details, see the Graphs tab above.