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We propose and demonstrate a bidirectional optical add-drop multiplexer for use in single-fiber bidirectional networks. With effective use of multiport circulators, fiber-Bragg gratings, and a single amplifier element, the new structure can add and/or drop channels in both directions and achieves more than 16 dB of bidirectional gain. The device utilizes Bragg gratings and light absorbers to remove Rayleigh backscattered and reflected light at the input stage. OCIS codes: 060.2330, 060.2340, 140.4480, 230.1480.

Cost effectiveness and energy efficiency have recently become two practical issues during access networks construction and operation. In this paper, we extend our previous proposal of a remote channel combine/split module for long-reach wavelength division multiplexed and time division multiplexed passive optical network systems. Besides previously discussed benefits on investment cost and energy efficiency under take-up-rate-adaptive mode, this study shows that proposed systems help achieve higher energy saving by adopting traffic-adaptive power management. Simulation results show up to 35% power consumption saving at the time of minimum traffic demands. Moreover, in terms of energy consumption over periodic time, we find a typical 20% energy saving can be achieved compared to conventional systems in fully operated stage. [ABSTRACT FROM PUBLISHER]

Abstract: We evaluate the performance of a novel technique to equalize power variation between optical bursts using feed-forward control of semiconductor optical amplifier gain. The technique enables large dynamic range power equalization of incoming optical bursts with up to 10dB power difference. Moreover, the technique can remove SOA-induced waveform distortion. We achieve more than 4dB sensitivity improvement with equalized burst power. [Copyright &y& Elsevier]

Abstract: We propose, a novel upstream transmission scheme for high speed wavelength division multiplexed passive optical networks. Upstream transmission at bit rate of 2.5Gb/s was demonstrated using a Fabry–Perot (FP) laser diode (LD) externally injected by a spectrum-sliced polarization-insensitive supercontinuum pulse source, located at central office. The impact of Rayleigh backscattering on transmission performance is also investigated. The proposed scheme is expected to be cost-effective since low-cost FP LDs are used for light sources. [Copyright &y& Elsevier]

An extended reach 10-Gb/s wavelength division multiplexing passive optical network (WDM-PON) system based on a low-bandwidth reflective semiconductor optical amplifier (RSOA) is demonstrated using a novel partial response equalization (PRE) scheme. The proposed technique has good performance-complexity tradeoff compared to traditional equalization methods. The intrinsic feature of the signal directly modulated by RSOA and the impact of dispersion on the modulated signal are investigated. The result shows that the shape of the RF spectrum of the received signal can be predicted. Moreover, one target response can be applied for a wide range of transmission distances by properly setting the equalizer parameters. It is confirmed experimentally and via simulation that the proposed system can achieve good performance over 0 to 75 km fiber link using PRE with the same setup. [ABSTRACT FROM PUBLISHER]

A time compression multiplexing (TCM)-based wavelength division multiplexing passive optical network (WDM-PON) using a reflective semiconductor optical amplifier (RSOA) is proposed, and its feasibility is experimentally demonstrated. In the proposed system, the RSOA pre-amplifies a 10 Gb/s downstream signal and modulates the RSOA output, wavelength-locked to the downstream signal, with a 1.25 Gb/s upstream signal simultaneously. The sensitivity of the downstream signal is improved by about 3 dB through the RSOA. The downstream and upstream signals have power penalties of about 0.1 dB and 1.1 dB, respectively, at bit error rates (BERs) of 10(-9) after 20 km transmission.

We experimentally demonstrate compensation of nonlinear distortion caused by the Kerr effect in a 3 × 32-Gbaud quadrature phase-shift keying (QPSK) wavelength-division multiplexing (WDM) transmission system. We use optical phase conjugation (OPC) produced by four-wave mixing (FWM) in a 7-mm long silicon nanowire. A clear improvement in Q-factor is shown after 800-km transmission with high span input power when comparing the system with and without the optical phase conjugation module. The influence of OSNR degradation introduced by the silicon nanowire is analysed by comparing transmission systems of three different lengths. This is the first demonstration of nonlinear compensation using a silicon nanowire.

We propose a new WDM-PON architecture using Fabry-Pérot laser diodes (FP-LDs) that are injection-locked by continuous wave (CW) seed light. The modulation characteristics of the CW light injection-locked FP-LD are first investigated. Both uplink and downlink transmissions at 10 Gb/s are experimentally demonstrated using the proposed CW injection-locked FP-LDs. It is shown that up to 16 laser cavity modes can be selectively injection-locked with side mode suppression ratio larger than 30dB. The effects of the location of FP-LD cavity modes, transmission distance, and injection wavelength detuning on the overall transmission performance are investigated. The possibility of eliminating polarization dependence of the proposed CW injection scheme is also experimentally demonstrated by properly configuring a depolarizer. The deployment cost for the proposed WDM PON is potentially low from the fact that the CW laser sources located at the central office can be shared by many WDM-PONs and low-cost FP-LDs are used as light sources for data rates as high as 10 Gb/s.