Multi-band CAP for Next-Generation Optical Access Networks Using 10-G Optics

• Published in: Journal of lightwave technology Vol. 36; no. 2; pp. 551 - 559
• Main Authors: Wei, Jinlong, Giacoumidis, Elias
• Format: Journal Article
• Language: English
• Published: New York IEEE 15.01.2018; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Adaptive optics; Blind equalization; carrierless amplitude and phase modulation; cycle slip; Decoding; Equalization; Erbium; Error correction; Fiber optic communications; Filtration; long reach passive optical network; modulation format; multi-modulus algorithm; Optical attenuators; Optical communication; Optical fibers; Optical filters; optical power budget; Optical transmitters; partial differential QAM; phase ambiguity; Preamplifiers; Quadrature amplitude modulation; Quantitative analysis; Recovery; Signal reconstruction; Signal transmission; Timing; timing error; timing recovery; Transceivers
• ISSN: 0733-8724; 1558-2213
• DOI: 10.1109/JLT.2017.2772894

40-Gb/s/λ multi-band carrierless amplitude and phase (CAP) modulation long-reach passive optical networks were demonstrated using 10-G class transceivers only. A major issue of multi-band CAP is that it is vulnerable to timing error, and this work has offered quantitative analysis about it in detail for the first time. A novel simple timing recovery approach, partial differential quadrature amplitude modulation constellation encoding and decoding schemes together with blind multimodulus algorithm equalization are proposed to address the issue efficiently, enabling zero-overhead signal recovery. Results show that it can offer excellent system tolerance to timing error of at least ±0.1 symbol period even for the highest frequency CAP sub-band. The characteristics of the transceiver are measured, and optimization of critical system parameters is performed including the CAP sub-band count, 10-G Mach-Zehnder intensity modulator operation conditions, optical launch power, and wavelength offset asymmetrical optical filtering. For downlink using erbium-doped fiber amplifier preamplifiers, successful 40-Gb/s multi-band CAP signal transmission over an 80-km (90-km) single-mode fiber is achieved with a link power budget of 33 dB (29 dB) considering a forward error correction threshold bit error ratio of 3.8 × 10 −3 .