Method and apparatus for use in the measurement of the wavelength or frequency of an optical signal
AssigneeJDS Fitel Inc.
InventorCarey M. Garrett
Life of this patent
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Abstract
The invention relates to a method of measuring the wavelength of an optical signal such as a light beam. The optical signal is directed toward a detector where its intensity is detected and stored. Several optical elements each having a different wavelength dependence are moved into the path of the optical beam one at a time and for each intensity is detected and stored. The wavelength of the optical signal is then approximately determined based upon the ratio of the detected intensity of the optical signal in the absence of any optical elements and the detected intensities of the optical signal in the presence of each optical element.
Claims13
A method of measuring the wavelength of an optical beam comprising the steps of:
- directing the optical beam along a path toward a detector capable of detecting an intensity of incident light:
- detecting a first intensity of the optical beam that is present at the detector absent an optical element having a substantial wavelength dependence:
- providing a first optical element having a first wavelength dependence, in the path of the optical beam and detecting a second intensity of the optical beam that is present at the detector;
- and, approximately determining the wavelength of the optical beam within first predetermined limits in dependence upon the ratio of the second detected intensity of the optical beam present at the detector and the first detected intensity of the optical beam present at the same detector in the absence of an optical element having a substantial wavelength dependence.
A method of measuring the wavelength of an optical light beam, comprising the steps of:
- directing an optical beam along a path toward a detector capable of detecting an intensity of incident light with a predetermined precision;
- detecting a first intensity of the optical beam that is present at the detector absent an optical element having a substantial wavelength dependence:
- providing a range for the wavelength;
- alternately optically aligning the path of the optical light beam and the detector and a plurality of periodic wavelength-dependent optical elements having a predetermined free spectral range, one at a time, such that each wavelength-dependent optical element is in the path;
- detecting a further intensity of light at the detector with at least some of the plurality of wavelength-dependent optical elements;
- and
- determining a measurement for the wavelength of the optical light beam, said measurement being determined in dependence upon the ratio of the further detected intensities of light at the detector and the first detected intensity of the light in the absence of an optical element having a substantial wavelength dependence.
Apparatus for measuring the wavelength of an optical beam comprising:
- an optical detector for detecting at least a portion of the optical beam;
- coupling means for directing the optical beam along a predetermined path toward the optical detector;
- at least a means for holding an optical filter in a first position in the path and in a second position out of the path;
- means for moving the at least a means for holding an optical filter from the first position to the second position;
- and,
- means for determining within predetermined limits, the wavelength of the light beam, in dependence upon at least an intensity of light at the detector when at least one of the at least a means for holding an optical filter is in the first position and the detected intensity of the optical beam present at the same detector when the at least a means for holding an optical filter is in the second position.
Apparatus for measuring the wavelength of an optical beam comprising:
- an optical detector for detecting an intensity of at least a portion of the optical beam;
- coupling means for directing the optical beam along a predetermined path toward the optical detector;
- a plurality of wavelength-dependent optical elements having a characteristic that varies with wavelength of light incident upon them;
- means for optically aligning at least some of the plurality of wavelength-dependent optical elements and the optical path defined between the detector and the coupling means such that one of the at least some wavelength dependent optical elements is in the path;
- means for detecting an intensity of light at the detector for each of the at least some wavelength dependent optical elements;
- and,
- means for determining within predetermined limits, the wavelength of the light beam, in dependence upon the detected intensities of light and the detected intensity of the light in the absence of an optical element having a substantial wavelength dependence.
Dependencies are inferred from the claim text.