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US 8,411,351 B2Granted
Optical differential phase-shift keyed signal demodulator
AssigneeFinisar Corporation
InventorsKevin McCallion, Xueyan Zheng
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Abstract
A phase-shift keyed signal demodulator and method for demodulating is disclosed. An example demodulator includes N filters that receive inputs from a splitter and include transmission functions offset from one another. N pairs of photodiodes receive the transmitted and reflected beams from each filter and a decoder converts the outputs of the pairs of photodiodes to one or more data symbols.
Claims13
A phase-shift keyed signal demodulator comprising:
- a splitter having an input and N outputs, the splitter configured to divide an input beam received at the input into N output beams emitted from the N outputs;
- N filters positioned to receive the N output beams and configured to reflect and transmit light associated with each of the N output beams based on a phase relationship between adjacent bits within each of the N output beams;
- N pairs of photodiodes each comprising first and second photodiodes positioned to receive reflected and transmitted light, respectively, from one of the N filters;
- and
- a decoder electrically coupled to the N pairs of photodiodes and programmed to output a data word having a length greater than or equal to N according to an evaluation of the outputs of the N pairs of photodiodes.
2 more elements
A method for demodulating a phase-shift keyed signal comprising:
- dividing the phase-shift keyed signal into N beams;
- transmitting each of the N beams through one of N filters, each of the N filters configured to reflect and transmit light associated with each of the N output beams based on a phase relationship between adjacent bits within each of the N output beams;
- for each filter, receiving light from one of the N beams at one of N photodiode pairs such that a portion of the light is reflected from the filter is received by a first photodiode of the photodiode pair and a portion of the light is transmitted through the filter is received by a second photodiode of the photodiode pair;
- processing outputs of the N photodiode pairs;
- and
- outputting a symbol word having a length greater than or equal to N according to the processing of the outputs of the N photodiode pairs.
3 more elements
Dependencies are inferred from the claim text.