All-optical processing devices for high-speed fiber communications

Ultra-fast all-optical devices are important in nowadays high-speed fiber communication. In this thesis, we propose and demonstrate a number of all-optical processing devices for clock frequency division, wavelength conversion and time-domain demultiplexing. Based on various semiconductor components including semiconductor optical amplifier, Fabry-Perot laser diode and electroabsorption modulator, high-speed all-optical devices are constructed with good performance.; A simple and robust technique of all-optical clock division is performed based on the period doubling phenomenon in directly modulated semiconductor lasers. All-optical clock-division from about 10 to 5GHz has been demonstrated. For the first time, we show that the output clock frequency can be optically controlled by a low power continuous-wave (cw) injected light signal. The transient characteristic is measured and a response shorter than 100 pico-second is obtained.; We demonstrate wavelength conversion using broad-band orthogonal pumps (BOP) four-wave mixing (FWM) in a semiconductor optical amplifier placed in a fiber-ring cavity. The widely-tunable all-optical wavelength converter operates with only one external cw pump laser. The wavelength-conversion efficiency has a variation smaller than 3 dB over a 40-nm range. Our result shows that the converter can operate essentially with any arbitrary input and output wavelengths within the range. With the scheme of polarization diversity, input polarization dependence of less than 0.5 dB is obtained. By replacing the cw pump laser with a pulsed laser source, a wavelength tunable time-division demultiplexer has been constructed and demonstrated. Signal demultiplexing from 10 Gb/s to 2.5 Gb/s is obtained with 1.5-dB power penalty.; With a further improvement of the setup, a polarization-insensitive widely tunable all-optical wavelength converter that operates without any external pump laser is demonstrated at 10 Gb/s. The scheme is based on a double-ring fiber laser incorporating a semiconductor optical amplifier. Using BOP FWM, a uniform (<3-dB variation) conversion efficiency over a 40-nm conversion range is obtained.; All-optical wavelength conversion and broadcasting up to 6 x 10 Gb/s have been demonstrated with an electroabsorption modulator based on cross-absorption modulation. Also, we demonstrate that the converter can stabilize the state-of polarization of the converted outputs with a degree of polarization larger than 98%. The results show the capability of reducing the amplitude jitter caused by varying states of the input polarizations.