Light sources are paired with optical power meters to create optical loss test sets or OLTs for testing optical loss through fiber. Light sources emitting light wavelengths between 850nm and 1300nm are for multimode applications.
Light sources emitting light wavelengths between 1310nm and 1550nm are for singlemode applications. 1490nm and 1625nm wavelengths are also for singlemode applications and are reserved for passive testing of optical networks. Multimode light sources typically use an LED while singlemode light sources typically use a laser source.
An optical light source injects a stable test light signal into a fiber. They often provide output light of more than one wavelength 850nm, 1310nm and 1550nm. Low power for short distance.
For reliable results, the power output of the light must be very stable over the period of the test, typically within 0.1dB over 1 hour. The output is able to be switched between a test tone of 2KHz, 270Hz or 10KHz and a continuous output called CW (Continuous Wave). The choice of test tones allows easy identification of fibers under test. Measurement should be carried out with unmodulated light (CW).
Before measurement, the light source and the laser diode module should be turned ON for at least 10 minutes (heating time) to ensure a stable light flow.
Choose a light source with the following feature
- Stabilized light sources.
- Laser or LED’s Wavelength.
- Multi-mode light sources with 850nm and 1300nm sources.
- Single mode light sources with 1310nm and 1550nm wavelengths.
- Universal connectors features.
- Standard batteries for stable performance.
- Small size & weight.
- 2Khz required for use with fiber identifiers.