Spectral efficiency of coded phase-shift keying for fiber-optic communication

• Published in: Journal of lightwave technology Vol. 21; no. 10; pp. 2438 - 2445
• Main Authors: Kramer, G., Ashikhmin, A., van Wijngaarden, A.J., Xing Wei
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.10.2003; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Additive white noise; Applied sciences; Bandwidth; Binary systems; Channels; Detectors; Exact sciences and technology; Fiber optics; Information, signal and communications theory; Keying; Modulation; Modulation, demodulation; Optical computing; Optical detectors; Optical fiber communication; Optical fibers; Optical modulation; Phase shift keying; Reed-Solomon codes; Signal and communications theory; Spectra; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; Testing; Transmission and modulation (techniques and equipments); Wavelength division multiplexing; Reed Solomon code; Performance evaluation; Differential detection; optical signal detection; phase-shift keying; optical transmitters; Quadrature phase shift keying; AWGN channels; Phase shift keying; Direct detection; Error correcting code; Optical fiber communication; Differential phase shift keying; Error correcting coding; Signal detection
• ISSN: 0733-8724; 1558-2213
• DOI: 10.1109/JLT.2003.817704

Several optical modulation and detection schemes are compared by computing their spectral efficiencies over additive white Gaussian noise channels. The bandwidth savings of differential quadrature phase-shift keying (D-QPSK) over both direct-detection on-off keying and differential binary phase-shift keying suggest that D-QPSK can improve the reach and efficiency of wavelength-division multiplexing systems. To test the theory, Reed-Solomon and low-density parity-check forward error correction codes are designed and evaluated. The codes generally behave as expected, except that for D-QPSK the gains are hampered by the differential detector. It is further shown that neither multiple-symbol differential detection nor decision-feedback detection is attractive when using strong codes.