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US 6,785,002 B2Granted
Variable filter-based optical spectrometer
AssigneeOptical Coating Laboratory, Inc.
InventorsSohrab Zarrabian, Fred J. Van Milligen, Kenneth P. Rosenberg, John D. Sonderman
Life of this patent
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Abstract
An optical spectrometer uses a tapered Fabry-Perot type variable optical filter in conjunction with an optical detector array. The filter can be a long-pass, short-pass, or narrow bandpass filter. The stability of the variable optical filter allows high resolution, depending on the number and spacing of the detectors used. In a further embodiment, signal-processing techniques are used to enhance the resolution of the spectrometer beyond the measured response.
Claims20
An optical spectrometer component comprising:
- a fiber optic input;
- a magnifying lens disposed to expand an optical signal from the fiber optic input to
- a collimating lens, the collimating lens disposed to provide a light beam to
- a variable bandpass filter having
- an etalon structure with
- a tapered spacer region being tapered along a taper direction, the variable bandpass filter having a thermal stability of less than or equal to 50 parts per million per degree Centigrade of ambient temperature change;
- and
- a linear optical detector array disposed along the taper direction.
5 more elements
An optical spectrometer component comprising:
- a fiber optic input;
- magnifying lens disposed to expand an optical signal from the fiber optic input to
- a collimating lens, the collimating lens disposed to provide a light beam to
- a variable bandpass filter having
- an etalon structure with
- a tapered spacer region being tapered along a taper direction, the variable filter having a thermal stability of less than or equal to 50 parts per million per degree Centigrade of ambient temperature change and a 50% bandwidth of less than or equal to about 0.6 nm at a center wavelength, the center wavelength being between about 1530-1600 nm;
- and
- a linear optical detector array disposed along the taper direction, the linear optical detector array having a length of less than or equal to 12 nm along the taper direction.
5 more elements
An optical transmission network comprising:
- an input optical fiber configured to carry a plurality of wavelength-division-multiplexed optical signals having nominal channel spacing of about 200 GHz or less;
- an output optical fiber;
- an optical tap disposed between the input optical fiber and the output optical fiber and configured to couple a portion of at least some of the plurality of wavelength-division-multiplexed optical signals to
- an optical spectrometer component having
- a variable filter including an etalon structure with at least one tapered spacer region being tapered along a taper direction with a thermal stability of less than 50 parts per million per degree Centigrade of ambient temperature change, and
- a detector array having n detectors affixed to the variable filter providing a nominal resolution;
- and
- an analyzer coupled to the optical spectrometer component so as to monitor each of the some of the plurality of optical signals and having a memory with a calibration array for m calibration wavelengths wherein m is greater than n to provide a spectrometer resolution that is greater than the nominal resolution.
5 more elements
An optical spectrometer comprising:
- a fiber optic input;
- collimating optics;
- a continuous linear variable filter having a tapered spacer region being tapered along a taper direction and having a thermal stability of less than 50 parts per million per degree Centigrade of ambient temperature change;
- a linear optical detector array having n detectors disposed along the taper direction and providing a nominal resolution;
- an analyzer electrically coupled to the linear optical detector array including a memory storing a calibration array for m calibration wavelengths wherein m is greater than n to provide a spectrometer resolution that is greater than the nominal resolution and wherein the collimating optics are disposed between the fiber optic input and the linear variable filter to illuminate the liner variable filter with a collimated light beam.
2 more elements
An optical transmission network comprising:
- an input optical fiber configured to carry a plurality of wavelength-division-multiplexed optical signals having nominal channel spacing of about 200 GHz or less;
- an output optical fiber;
- an optical tap disposed between the input optical fiber and the output optical fiber and configured to couple a portion of at least some of the plurality of wavelength-division-multiplexed optical signals to
- an optical spectrometer having a nominal resolution less than or equal to 8 Angstroms and a thermal stability of less than 50 parts per million per degree Centigrade of ambient temperature change and including
- a variable filter with at least one tapered spacer region being tapered along a taper direction, and
- a detector array affixed to the variable filter;
- each
- an analyzer coupled to the optical spectrometer component so as to monitor each of the some of the plurality of optical signals.
5 more elements
Dependencies are inferred from the claim text.