Optical wavelength meters or OSA
A wavelength calibration service has been established to support fibre optic communication systems. The service operates from 1270 to 1650 nm and is optimised for the 1300 and 1550 nm telecoms windows. The wavelength scale of optical spectrum analysers and wavelength meters can be calibrated in addition to measurements of the wavelength of cw fibre optic sources.
Wavelength calibrations are made using a tuneable laser locked to atomic or molecular transition in both the 1300 and 1550 nm windows.
Wavelength Meters
Calibration of wavelength scale using a laser locked to molecular and excited-state atomic transitions. Measurements are possible over the wavelength range 1275 nm to 1650 nm. Transitions cover all bands O to U.
Typical sources used are:
| Source* | Wavelength (nm) |
| Krypton optogalvanic | 1286.541 and 1547.826 |
| CO unsaturated absorption | lines in the range 1560 - 1568 |
| 13C2H2 Acetylene unsaturated absorption | lines in the range 1520 - 1550 |
* Other sources are available on request. UKAS accredited best measurement capability is ± 0.13 pm.
A copy of a typical Calibration Certificate is available to download.
Optical Spectrum Analyser (OSA)
Calibration of the wavelength scale of an OSA is made by employing a number of different techniques. A single wavelength point calibration can be made using a transition locked laser source. The wavelength scale linearity can be determined by using an etalon calibration artefact or a tuneable laser and wavelength meter combination. Both of these can provide a full calibration covering the range 1285 to 1665 nm. Uncertainties are dependent on the device under test, but for a modern instrument a figure of around ± 10.5 pm is expected.
Absolute power scale and power linearity measurements are possible on request.
Reference sources
Calibration of the wavelength of single-line, DFB and frequency stabilised fibre optic sources. Measurements are made by comparing the wavelength of the source under test to that of a reference source of known wavelength using a calibrated wavelength meter. Higher accuracy measurements are possible by employing a heterodyne measurement technique; this measures directly the frequency difference between a known reference source and the source under test.
Associated service
An on-site calibration service for wavelength meters and optical spectrum analysers is also available on request.
Contact
Customer Service tel: +44 20 8943 6151
E-mail: optical_enquiries@npl.co.uk