In this paper, a scheme for all-optical AND gate which exploits the cross-phase modulation (XPM) effect in an
asymmetric semiconductor-optical-amplifier-assisted Mach-Zehnder Interferometer (SOA-MZI) has been proposed for
the first time. No additional input beam such as a clock signal or continuous light is employed in the design, which is
required in other AND operations. The scheme is validated and the system performance under various parameters is
investigated through numerical simulations. This logic gate is helpful for future all-optical signal processing
A novel self-synchronization scheme is proposed that utilizes both cross gain modulation (XGM) and phase modulation, including self-phase modulation (SPM) and cross-phase modulation (XPM), in a semiconductor optical amplifier (SOA). The scheme consists of an SOA and a delay line interferometer. It is simple, integrable, and does not require any special marker pulses. With a proper design of the SOA parameters and interferometer delay time, a synchronization clock with an intensity contrast ratio of more than 20 dB can be obtained from return-to-zero (RZ) pseudorandom bit sequences (PRBSs) at different operation speeds.
A novel all-optical header extraction scheme based on cross gain modulation and self-frequency shift in SOA is proposed and demonstrated in this paper for the first time. In the proposed technique, the header is assumed to be encoded in 2.5Gb/s PRBS and inserted ahead of a payload with 40Gb/s ratio. With theoretical
simulation, the feasibility and property of the proposed scheme are demonstrated and analyzed respectively. Results indicate the performance of the technique is influenced greatly by the parameters of SOA and optical bandpass filter (OBF), such as the carrier lifetime and the 3-dB bandwidth etc. With properly chosen parameters of SOA and OBF, the transmitted energy of the payload can be suppressed effectively and the header can be extracted successfully from the input packet.
In this paper, we present the design and fabrication of a novel compact broad-band isolator with high isolation performance. With properly adding waveplates into the scheme, the fabricated device is demonstrated to achieve an isolation value of more than 40dB covering a broad-band wavelength range of 300nm in simulation. Its temperature insensitive and super low PMD character also has been demonstrated. Theoretical analysis and experimental results show each set of parameters concerning the isolator with high performance, which indicates the proposed technique is promising in the application of optical networks.
Presented in this paper is the design and fabrication of a novel polarization-insensitive optical circulator with multiport. For an optical circulator with n ports, it guides the signal from port 1 into port 2, port 2 into port 3, and so on, till port n into port 1. As a result, the circulator provides further chromatic dispersion compensation and routing function, etc. In this paper, two designs of circulators concerning with odd and even port compact are presented. The port number regarding to each scheme can be arbitrarily designed according to system requirement. Experiments have been conducted to show the performance of our designs on a 3-port and 4-port loop circulators. Key parameters of each scheme are also presented, including the insertion loss (IL), the polarization dependence (PDL), the isolation performance (IS), return loss (RL) and the crosstalk within its working wavelength. Results from the experiments show that the fabricated circulator provides an excellent performance for each set of system parameters. This circulator provides a new possibility for developing compact nonreciprocal devices in the field of optical communications.