Wavelength manager
AssigneeMarconi Communications, Inc.
InventorNigel R Wood
Life of this patent
Estimating the term…
Abstract
Scanning based wavelength measurement systems which are suitable for both localised and distributed WDM, High Density WDM, and coherent systems are based around the use of a fixed cavity Fabry-Perot Etalon which when the output of a tuneable laser is passed through it produces a number of reference equispaced transmission maxima. These maxima are used in a Scanning Heterodyne or Scanning Filter based Spectrometer for detection of the wavelength position of the transmitter.
Claims9
A method of thermally calibrating a scan range of an optical spectrometer operative for measuring frequencies of a plurality of optical transmitter signals from a plurality of optical transmitters, comprising the steps of:
- a) optically scanning a Fabry-Perot etalon with a local oscillator to generate a plurality of transmission peaks equispaced in frequency;
- b) detecting the transmitter signals from the transmitters using the local oscillator;
- c) detecting an optical frequency reference signal using the local oscillator;
- d) determining a scan offset by comparing, in time, one of the peaks with the reference signal, the scan offset being a function of the ambient temperature of the etalon;
- and
- e) offsetting, in time, the transmitter signals with the scan offset to obtain thermally-corrected times for the transmitter signals simultaneously with the measuring by the spectrometer.
An arrangement for thermally calibrating a scan range of an optical spectrometer operative for measuring frequencies of a plurality of optical transmitter signals from a plurality of optical transmitters, comprising:
- a) means for optically scanning a Fabry-Perot etalon with a local oscillator to generate a plurality of transmission peaks equispaced in frequency;
- b) means for detecting the transmitter signals from the transmitters using the local oscillator;
- c) means for detecting an optical frequency reference signal using the local oscillator;
- d) means for determining a scan offset by comparing, in time, one of the peaks with the reference signal, the scan offset being a function of the ambient temperature of the etalon;
- and
- e) means for offsetting, in time, the transmitter signals with the scan offset to obtain thermally-corrected times for the transmitter signals simultaneously with the measuring by the spectrometer.
Dependencies are inferred from the claim text.