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US 10,225,020 B2Granted
Systems and methods for demodulation of PSK modulated optical signals
AssigneeRaytheon Company
InventorsBenjamin P. Dolgin, Gary M. Graceffo, Andrew Kowalevicz
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Abstract
Optical signal receivers and methods are provided that include first and second optical resonators, each of which receives a portion of an arriving optical signal. The first optical resonator is tuned to a carrier wavelength and accumulates resonant optical signal energy whose output is disturbed responsive to a transition in the arriving optical signal. The second optical resonator is detuned from the carrier wavelength but also exhibits a disturbed output responsive to the transition in the arriving optical signal. Detectors detect the output disturbances from the two optical resonators to determine characteristics of the transition in the arriving optical signal.
Claims20
An optical signal receiver comprising:
- a first optical resonator configured to receive an arriving optical signal and to emit first output optical signal energy, the first optical resonator including an optical length less than half of a distance associated with a symbol length of the arriving optical signal, such that the first optical resonator is configured to accumulate resonant optical signal energy inside the first optical resonator based at least in part on the received arriving optical signal to cause the first output optical signal energy to approach a first steady-state intensity value, and to cause a first disturbance in the first output optical signal energy responsive to a transition in the arriving optical signal, the first optical resonator being tuned to a carrier wavelength of the arriving optical signal and a resonant wavelength of the resonant optical signal energy corresponding to the carrier wavelength of the arriving optical signal;
- a second optical resonator configured to receive the arriving optical signal and to emit second output optical signal energy, the second optical resonator being further configured to cause a second disturbance in the second output optical signal energy responsive to the transition in the arriving optical signal, the second optical resonator being detuned from the carrier wavelength of the arriving optical signal;
- a first detector configured to detect the first disturbance in the first output optical signal energy and to determine a first characteristic of the transition in the arriving optical signal;
- and
- a second detector configured to detect the second disturbance in the second output optical signal energy and to determine a second characteristic of the transition in the arriving optical signal.
2 more elements
A method of detecting information encoded in an optical signal, the method comprising:
- receiving the optical signal at each of a first optical resonator and a second optical resonator, each of the first optical resonator and the second optical resonator including an optical length less than half of a distance associated with a symbol length of the optical signal;
- accumulating optical signal energy in each of the first optical resonator and the second optical resonator based on the optical signal;
- achieving a resonance condition of the accumulated optical signal energy inside the first optical resonator at a carrier wavelength of the optical signal;
- emitting a first output optical signal from the first optical resonator and emitting a second output optical signal from the second optical resonator, first and second steady-state intensity values of the first and second output optical signals, respectively, being based at least in part on the accumulated optical signal energy;
- varying a first intensity level of the first output optical signal from the first steady-state intensity level responsive to a modulation transition in the optical signal;
- varying a second intensity level of the second output optical signal from the second steady-state intensity level responsive to the modulation transition in the optical signal;
- detecting the first and second output signals;
- and
- determining a modulation characteristic of the optical signal based on the variations in the first and second intensity levels.
6 more elements
An optical receiver comprising:
- a first resonator configured to at least partially accumulate optical signal energy, having an aperture to allow a portion of an optical signal to enter, an optical length less than half of a distance associated with a symbol length of the optical signal, and an output to provide a first output signal, the first resonator configured to cause the first output signal to exhibit variations based at least in part upon a magnitude of a phase shift in the optical signal;
- a second resonator configured to at least partially accumulate optical signal energy, having an aperture to allow a portion of the optical signal to enter and an output to provide a second output signal, the second resonator configured to cause the second output signal to exhibit variations based at least in part upon a direction of the phase shift in the optical signal;
- and
- a receiver configured to receive the first and second output signals and to determine information encoded by the phase shift in the optical signal.
1 more element
Dependencies are inferred from the claim text.