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US 7,605,974 B1Granted
Method and apparatus for PPM demodulation using a semiconductor optical amplifier
AssigneeHRL Laboratories, LLC
InventorStanislav I. Ionov
Life of this patent
Estimating the term…
Abstract
An optical pulse position modulation receiver relying on the gain dynamics in a semiconductor optical amplifier (SOA). Optical PPM signal pulses and periodic optical clock pulses at a different frequency and/or polarization than the signal pulses are coupled into an SOA. Due to the high optical power of the clock pulses, the SOA gain will drop to a small value after each clock pulse. The SOA will then amplify each signal pulse that follows the clock pulse, and the gain will depend on the delay between the signal pulse and the preceding optical clock pulse. The optical output of the SOA can then be converted to an electrical signal by a photodetector.
Claims21
An optical pulse position modulation receiver comprising:
- a semiconductor optical amplifier having an input receiving an optical pulse position modulated signal and receiving optical clock pulses;
- a filter apparatus receiving an output of said semiconductor optical amplifier, said filter apparatus suppressing optical clock pulses output by said semiconductor optical amplifier and passing an amplified optical pulse position modulated signal output by said semiconductor optical amplifier;
- and
- an optical to electric converter receiving said amplified optical pulse position modulated signal,
- wherein said optical clock pulses have an optical power at a level to reduce the stimulated emission transition of said semiconductor optical amplifier, wherein said optical clock pulses have a polarization different than a polarization of said optical pulse position modulated signal and the receiver further comprises:
- a first polarization coupler with a first input receiving said optical pulse position modulated signal and a second input receiving said optical clock pulses and having an output coupled to said semiconductor optical amplifier;
- and
- wherein the filter apparatus comprises:
- a second polarization coupler with an input receiving an output of said semiconductor optical amplifier, and having a first output configured to output optical signals having the polarization of said optical clock pulses and having a second output configured to couple optical signals having the polarization of said optical pulse position modulated signal to said optical to electric converter.
6 more elements
An optical pulse position modulation receiver comprising:
- a semiconductor optical amplifier having an input receiving an optical pulse position modulated signal and receiving optical clock pulses;
- a filter apparatus receiving an output of said semiconductor optical amplifier, said filter apparatus suppressing optical clock pulses output by said semiconductor optical amplifier and passing an amplified optical pulse position modulated signal output by said semiconductor optical amplifier;
- and
- an optical to electric converter receiving said amplified optical pulse position modulated signal,
- wherein said optical clock pulses have an optical power at a level to reduce the stimulated emission transition of said semiconductor optical amplifier, wherein said optical clock pulses have an optical wavelength different than that of the optical pulse position modulated signal and the receiver further comprises:
- an optical coupler with a first input receiving said optical pulse position modulated signal and a second input receiving said optical clock pulses and an output coupled to said semiconductor optical amplifier;
- and wherein the filter apparatus comprises:
- a bandpass filter with an input coupled to an output of said semiconductor optical amplifier, said bandpass filter suppressing optical signals at the optical wavelength of the optical clock pulses and passing optical signals at the optical wavelength of the optical pulse position modulated signal.
5 more elements
An optical pulse position modulation receiver comprising:
- a semiconductor optical amplifier having an input receiving an optical pulse position modulated signal and receiving optical clock pulses;
- a filter apparatus receiving an output of said semiconductor optical amplifier, said filter apparatus suppressing optical clock pulses output by said semiconductor optical amplifier and passing an amplified optical pulse position modulated signal output by said semiconductor optical amplifier;
- and
- an optical to electric converter receiving said amplified optical pulse position modulated signal,
- wherein said optical clock pulses have an optical power at a level to reduce the stimulated emission transition of said semiconductor optical amplifier, wherein said optical clock pulses have an optical wavelength and a polarization different than an optical wavelength and polarization of the optical pulse position modulated signal and the receiver further comprises:
- an optical coupler with a first input receiving said optical pulse position modulated signal and a second input receiving said optical clock pulses and an output coupled to said semiconductor optical amplifier;
- and
- wherein the filter apparatus comprises:
- a polarization coupler having an input receiving an output of said semiconductor optical amplifier, and having a first output configured to output optical signals having the polarization of said optical clock pulses and having a second output configured to couple optical signals having the polarization of said optical pulse position modulated signal to said optical to electric converter;
- or
- a bandpass filter with an input coupled to an output of said semiconductor optical amplifier, said bandpass filter suppressing optical signals at the optical wavelength of the optical clock pulses and passing optical signals at the optical wavelength of the optical pulse position modulated signal to said optical to electric converter;
- or
- a polarization coupler and a band pass filter combination, the polarization filter of said combination having an input receiving an output of said semiconductor optical amplifier, and the polarization coupler of said combination having a first output configured to output optical signals having the polarization of said optical clock pulses and having a second output configured to couple optical signals having the polarization of said optical pulse position modulated signal to an input of said bandpass filter of said combination, said bandpass filter of said combination suppressing optical signals at the optical wavelength of the optical clock pulses and passing optical signals at the optical wavelength of the optical pulse position modulated signal to said optical to electric converter.
10 more elements
An optical pulse position modulation receiver comprising:
- a semiconductor optical amplifier having an input receiving an optical pulse position modulated signal and receiving optical clock pulses;
- a filter apparatus receiving an output of said semiconductor optical amplifier, said filter apparatus suppressing optical clock pulses output by said semiconductor optical amplifier and passing an amplified optical pulse position modulated signal output by said semiconductor optical amplifier;
- and
- an optical to electric converter receiving said amplified optical pulse position modulated signal,
- wherein said optical clock pulses have an optical power at a level to reduce the stimulated emission transition of said semiconductor optical amplifier, wherein said optical to electric converter comprises a balanced detector, said balanced detector having a first input receiving said optical pulse position modulated signal and a second input receiving said amplified optical pulse position modulated signal.
2 more elements
An optical pulse position modulation detector comprising:
- optical amplification means having an input receiving optical pulse position modulated pulses and receiving optical clock pulses, said optical amplification means providing a gain for each pulse of said optical pulse position modulated pulses proportional to a delay from a preceding optical clock pulse of said optical clock pulses;
- filtering means receiving an output of said optical amplification means, said filtering means suppressing optical clock pulses output by said optical amplification means and passing amplified optical pulse position modulated pulses output by said optical amplification means;
- and
- optical to electric conversion means receiving said amplified optical pulse position modulated pulses and providing an electrical output corresponding to said amplified optical pulse position modulated pulses.
1 more element
Dependencies are inferred from the claim text.