PARTIAL DPSK (PDPSK) TRANSMISSION SYSTEMS
An optical receiver includes a demodulator having a delay interferometer comprising an optical input that receives a phase modulated optical signal from a bandwidth limited transmission system. The delay interferometer has a free spectral range that is larger than a symbol rate of the phase modulated optical signal by an amount that improves receiver performance. The receiver also includes a differential detector having a first and a second photodetector. The first photodetector is optically coupled to the constructive optical output of the delay interferometer. The second photodetector is optically coupled to the destructive optical output of the delay interferometer. The differential detector combines a first electrical detection signal generated by the first photodetector and a second electrical detection signal generated by the second photodetector to generate an electrical reception signal.
1 . An optical receiver comprising:
a. a demodulator having a delay interferometer comprising an optical input that receives a phase modulated optical signal from a bandwidth limited transmission system, a constructive optical output, and a destructive optical output, the delay interferometer having a free spectral range that is larger than a symbol rate of the phase modulated optical signal by an amount that improves receiver performance; and
b. a differential detector comprising a first and a second photodetector, the first photodetector being optically coupled to the constructive optical output of the delay interferometer, the second photodetector being optically coupled to the destructive optical output of the delay interferometer, the differential detector combining a first electrical detection signal generated by the first photodetector and a second electrical detection signal generated by the second photodetector to generate an electrical reception signal.