摘要:
An optical pulse pattern generator can generate optical pulse signals with various periods and patterns. It supplies an optical pulse from an optical pulse source to a variable optical delay line circuit including cascade-connected characteristic-variable asymmetrical Mach-Zehnder interferometers via an optical combiner and splitter. The optical pulse is fed back to the optical combiner and splitter from the final stages of the cascade-connected characteristic-variable a symmetrical Mach-Zehnder interferometers via an optical exclusive OR circuit and optical amplifier. Making directional couplers with variable coupling ratio, and directional couplers with variable coupling ratio in operation can cause the final stage of the cascade-connected characteristic-variable asymmetrical Mach-Zehnder interferometer to produce a random pulse train.
摘要:
An optical CDMA encoder-decoder is constructed by combining arrayed-waveguide gratings, matrix optical switches, and delay lines, otherwise by combining arrayed-waveguide grating and variable delay lines, thus providing an encoding process that a wavelength change with respect to time in optical pulses. The light includes a wide spectrum band width inserted into a CDMA encoder/decoder and is demultiplexed by arrayed-waveguide gratings. Each wave length according to the demultiplexed spectrum component spreads out in the time region based on delay time differences produced by delay lines having differential optical lengths. Thus, in CDMA, the dependency of wavelengths on delay time can be set arbitrarily.