Abstract: Described are an FSK modulator and a method for large-alphabet FSK modulation. The FSK modulator and the method are based on filtering of a multi-tone optical source such as a mode-locked laser which provides a comb distribution of tones. A frequency-selective component selects for transmission a subset of the tones. In various embodiments the frequency-selective component is a Mach-Zehnder interferometer filter or a microring resonator filter. A second frequency-selective component selects a subset of the tones from the comb distribution provided by the first frequency-selective component. Still more frequency-selective components can be used according to the number of tones supplied by the multi-tone optical source to the FSK modulator. The optical signal exiting the last frequency-selective component includes only a single tone which corresponds to the symbol to be transmitted.

Abstract: Described are an FSK modulator and a method for large-alphabet FSK modulation. The FSK modulator and the method are based on filtering of a multi-tone optical source such as a mode-locked laser which provides a comb distribution of tones. A frequency-selective component selects for transmission a subset of the tones. In various embodiments the frequency-selective component is a Mach-Zehnder interferometer filter or a microring resonator filter. A second frequency-selective component selects a subset of the tones from the comb distribution provided by the first frequency-selective component. Still more frequency-selective components can be used according to the number of tones supplied by the multi-tone optical source to the FSK modulator. The optical signal exiting the last frequency-selective component includes only a single tone which corresponds to the symbol to be transmitted.

Abstract: Described are an FSK modulator and a method for large-alphabet FSK modulation. The FSK modulator and the method are based on filtering of a multi-tone optical source such as a mode-locked laser which provides a comb distribution of tones. A frequency-selective component selects for transmission a subset of the tones. In various embodiments the frequency-selective component is a Mach-Zehnder interferometer filter or a microring resonator filter. A second frequency-selective component selects a subset of the tones from the comb distribution provided by the first frequency-selective component. Still more frequency-selective components can be used according to the number of tones supplied by the multi-tone optical source to the FSK modulator. The optical signal exiting the last frequency-selective component includes only a single tone which corresponds to the symbol to be transmitted.

Abstract: Described is an all-optical switch that is significantly insensitive to polarization instabilities. The optical switch can be configured as an ultrafast logic gate, a switch for ultrafast communication systems or a key component of an all-optical regenerator. Performance is independent of the statistical characteristics of the data controlling the switch. The switch includes a birefringent optical channel in communication with one end of a nonlinear optical channel through a coupler and a polarization rotation mirror in communication with the other end of the nonlinear channel. An optical data pulse for controlling the switching function is provided to one port of the coupler.

Abstract: Described is an all-optical switch that is significantly insensitive to polarization instabilities. The optical switch can be configured as an ultrafast logic gate, a switch for ultrafast communication systems or a key component of an all-optical regenerator. Performance is independent of the statistical characteristics of the data controlling the switch. The switch includes a birefringent optical channel in communication with one end of a nonlinear optical channel through a coupler and a polarization rotation mirror in communication with the other end of the nonlinear channel. An optical data pulse for controlling the switching function is provided to one port of the coupler.