Swept Source Lasers


Rapidly Swept Tunable Laser

  • Center Wavelength: 1325 nm
  • Broad 3 dB Wavelength Range: 125 nm
  • Designed for Swept-Source OCT and OEM Applications
  • Integrated MZI Enables Easy Wavenumber Triggering


  • Ideal for Optical Coherence Tomography
  • Center Wavelength: 1325 nm
  • 3 dB Tuning Range: 125 nm
  • Real-Time 2D Imaging at 16,000 Lines per Second in OCT Applications

Thorlabs' SL1325-P16 OCT-proven frequency swept tunable laser is specifically designed for Swept Source Optical Coherence Tomography (SS-OCT) and Optical Frequency Domain Reflectometry (OFDR) applications. This laser utilizes Thorlabs' patented Cat-Eye external cavity laser design to continuously sweep across a broad wavelength range. Each laser includes an integrated Mach-Zehnder Interferometer, which can be used for easy wavenumber triggering. A BNC connection is located on the rear panel of the laser to access the interferometer's signal.

The SL1325-P16 has a typical center wavelength of 1325 nm, which is able to penetrate multi-layer biological tissues. The laser can continuously scan at a rate of 16 kHz over its tuning range to provide real-time 2D and 3D imaging capabilities when used in an OCT system. The image at the top right corner of this page shows an example screenshot of 2D imaging that is possible when building a SS-OCT system with these lasers. Please see the OCT Integration tab for details on how the lasers are used in our SS-OCT imaging systems. The broad wavelength tuning range of this laser is important for SS-OCT because the broader the spectral range, the higher axial resolution.

Front Panel Controls
The front overlay of this laser features a power switch, a Laser Enable button, a Tuning Enable button, an FC/APC fiber connection, and indicator lights. When the power switch is flipped on, a "Power On" light will illuminate. The Laser Enable button will turn the laser on, but the laser's output will not be swept across its wavelength range until the Tuning Enable button is pressed. Indicator lights alert the user if the laser has not yet reached its set temperature (during startup) or if the laser has overheated. If the laser has overheated, the unit will automatically turn off the laser, scanner, and TEC to protect them from damage. Once the unit has cooled, the TEC will turn back on, but the laser and tuning must be re-enabled by the user.


Item #Center Wavelength*3 dB Tuning Range*Optical Power*
SL1325-P16 1325 nm 125 nm 15 mW


Center Wavelength 1310 nm 1325 nm 1340 nm
Tuning Range (-3 dB Cutoff Point) 110 nm 125 nm -
Tuning Range (-10 dB Cutoff Point) 120 nm 140 nm -
Repetition Rate 15.7 kHz 15.9 kHz 16.1 kHz
Average Optical Output Power* 10 mW 15 mW -
Optical Power Stability** - ±0.5 dB -
Optical Isolation 50 dB
Linear Polarization >80:1
Coherence Length 5 mm 6 mm 7 mm
Operating Temperature 10 °C 25 °C 40 °C
Storage Temperature 10 °C 25 °C 40 °C
Humidity >85%, Non-condensing Environment
Laser Classification (per IEC 60825-1) Class 1M
Physical Size (w x d x h) 315 mm x 295 mm x 146 mm

*Averaged over 1 s
**Forward to forward scan or backward to backward scan during 1 hr usage



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