The Thorlabs WM202 Wavelength Meter measures the wavelength, coherence length, and power of a CW laser that is coupled to the device through an FC/APC input fiber by using a scanning Michelson interferometer and a reference laser. The wavelength measurement absolute accuracy is 1 ppm when using the internal reference laser, or 0.3 ppm when using an external reference laser with ±25 MHz accuracy (after a 15-minute warm-up, if the device is calibrated annually with a known wavelength laser). The annual calibration can be performed by the user if an appropriate laser is available or by Thorlabs, if needed.
- 600 to 1700 nm Wavelength Meter With Accuracy as Low as 0.3 ppm
- Simultaneously Measure the Wavelength, Coherence Length, and Power of a CW Laser with Bandwidth ≤10 GHz
- Control the Device through the Touchscreen Interface, Thorlabs' Software, or SCPI Commands
Features
- Scanning Michelson Interferometer with Internal Stable Reference Laser
- Measures the Wavelength, Coherence Length, and Power of a CW Laser from 600 to 1700 nm
- Use with Internal Reference Laser or an External Reference Laser (Thorlabs' LLD1530 Frequency-Locked Laser Recommended)
- Slow Scanning Mode at 1 Hz or Fast Scanning Mode at 10 Hz to Trade Off Accuracy for Measurement Speed
- Device Control Options:
- Directly With the Touchscreen Interface
- Remotely With a PC and Thorlabs’ OPM Software (USB or Ethernet Connection)
- Monitor Data Through a Web Viewer (Ethernet)
- Remote Control With SCPI Commands (USB, Ethernet, or RS232 Connection)
- Configurable Analog Output Error Signal for Feedback Loops
The WM202 Wavelength Meter is a compact, general-purpose wavelength meter designed for measuring the center wavelength of a CW laser from 600 to 1700 nm (bandwidth ≤10 GHz) with an absolute accuracy down to 0.3 parts per million. The power and coherence length of the laser are also measured simultaneously, allowing for the single longitudinal mode behavior of the input laser to be monitored. The input light is coupled into the device using an FC/APC fiber.
The wavelength meter consists of a scanning Michelson interferometer with an internal reference laser, enabling high-accuracy measurements and a quick start-up. Please see the Theory tab for details on the theory of operation of the device. The internal temperature-stabilized, distributed feedback (DFB) reference laser provides an absolute measurement accuracy of 1 ppm (1.5 pm at 1500 nm, 200 MHz at 200 THz). For improved accuracy, the wavelength meter can be used with an external reference laser (required accuracy ±25 MHz) in the 1520 to 1580 nm range, such as Thorlabs' LLD1530 Frequency-Locked Laser, with an accuracy of 0.3 ppm (0.45 pm at 1500 nm, 60 MHz at 200 THz).
Figure G1.1 The measurement absolute accuracy in wavelength and frequency are graphed, for reference. The graph corresponds to the 1 ppm accuracy specified when using the internal reference after 15 minute warm-up, if the instrument is calibrated annually.
| Table 1.1 Key Specifications | |
|---|---|
| Item # | WM202 |
| Wavelength Rangea | 600 to 1700 nm |
| Maximum Input Bandwidth | 10 GHz |
| Minimum Required Input Powerb | 2 to 40 µW |
| Wavelength Measurement Absolute Accuracy, Internal Reference | 1 ppm (1.5 pm at 1500 nm, 200 MHz at 200 THz)c,d |
| Wavelength Measurement Absolute Accuracy, External Reference | 0.3 ppm (0.45 pm at 1500 nm, 60 MHz at 200 THz)c,d,e |
| External Reference Laser Input | Wavelength Range: 1520 - 1580 nm Input Power Range: 0.2 - 5 mW Required Accuracy: ±25 MHz (±0.2 pm at 1550 nm) Maximum Bandwidth: 1 GHz |
| Power Measurement Accuracyf | ±1 dB |
| Coherence Length Measurement Rangeg | <10 mm/<1 mm |
| Measurement Speedg | 1 Hz/10 Hz |
| Optical Return Loss | >50 dB |
| Fiber Connector Type | Input: FC/APC, Wide Key (2.2 mm) External Reference Input: FC/APC, Narrow Key (2.0 mm) |