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A self-adaptive probabilistically shaped (PS) star-carrier-less amplitude/phase (CAP)-24 modulated passive optical network (PON) is proposed to adaptively adjust the probability distribution of the signal points. The proposed scheme is capable of accommodating different channels and transmission distances to obtain the optimal probability distribution. The employment of the simulated annealing algorithm in the constellation can significantly reduce the average signal power, as well as facilitating the flexible deployment and enhancement of the PON system. The experimental results show that the self-adaptive optimal signal transmission can be acquired when the probability ratio of signal points located in the three well-designed rings of the CAP-24 constellation is set as 0.724:0.175:0.101. Compared with the general PS-star-CAP-32 signal, the self-adaptive PSstar- CAP-24 signal has a gain of 1.5 dB at the 7% hard decision forward error correction (HD-FEC) limit. What is more, the proposed PS self-adaptive PS-star-CAP-24 can outperform the general PS-star-CAP-24 constellation by 0.2 dB at the 7% HD-FEC limit. [ABSTRACT FROM AUTHOR]

The wavelength-division multiplexing passive optical network (WDM-PON) is a potential technology to carry multiple services in an optical access network. However, it has the disadvantages of high cost and an immature technique for users. A software-defined WDM/time-division multiplexing PON was proposed to meet the requirements of high bandwidth, high performance, and multiple services. A reasonable and effective uplink dynamic bandwidth allocation algorithm was proposed. A controller with dynamic wavelength and slot assignment was introduced, and a different optical dynamic bandwidth management strategy was formulated flexibly for services of different priorities according to the network loading. The simulation compares the proposed algorithm with the interleaved polling with adaptive cycle time algorithm. The algorithm shows better performance in average delay, throughput, and bandwidth utilization. The results show that the delay is reduced to 62% and the throughput is improved by 35%. [ABSTRACT FROM AUTHOR]

An architecture for flattened and broad spectrum multicarriers is presented by generating 60 comb lines from pulsed laser driven by user-defined bit stream in cascade with three modulators. The proposed scheme is a cost-effective architecture for optical line terminal (OLT) in wavelength division multiplexed passive optical network (WDM-PON) system. The optical frequency comb generator consists of a pulsed laser in cascade with a phase modulator and two Mach-Zehnder modulators driven by an RF source incorporating no phase shifter, filter, or electrical amplifier. Optical frequency comb generation is deployed in the simulation environment at OLT in WDM-PON system supports 1.2-Tbps data rate. With 10-GHz frequency spacing, each frequency tone carries data signal of 20 Gbps-based differential quadrature phase shift keying (DQPSK) in downlink transmission. We adopt DQPSK-based modulation technique in the downlink transmission because it supports 2 bits per symbol, which increases the data rate in WDM-PON system. Furthermore, DQPSK format is tolerant to different types of dispersions and has a high spectral efficiency with less complex configurations. Part of the downlink power is utilized in the uplink transmission; the uplink transmission is based on intensity modulated on-off keying. Minimum power penalties have been observed with excellent eye diagrams and other transmission performances at specified bit error rates. [ABSTRACT FROM AUTHOR]