Abstract: The invention provides a tunable coherent optical receiver and a related method wherein the receiver uses low-frequency trace-tone modulation of optical WDM channels at transmission as channel IDs in order to detect which optical channels are present in the received optical WDM signal. The receiver than discriminates between the thereby detected optical channels by tuning a local oscillator to one of the received optical channels as determined based on the presence of the low-frequency tones in the received optical signal.

Abstract: The invention provides a tunable coherent optical receiver and a related method wherein the receiver uses low-frequency trace-tone modulation of optical WDM channels at transmission as channel IDs in order to detect which optical channels are present in the received optical WDM signal. The receiver than discriminates between the thereby detected optical channels by tuning a local oscillator to one of the received optical channels as determined based on the presence of the low-frequency tones in the received optical signal.

Abstract: A modulation system and a method for generating a return-to-zero (RZ) optical data signal are provided. The modulation system comprises a Mach-Zehnder (MZ) modulator and a drive circuit, which includes a logic XOR gate and a differential amplifier. The logic XOR gate applies a logic XOR operation to a non-return-to-zero (NRZ) electrical data signal and an inverse of an electrical clock signal to generate an electrical intermediate signal. The differential amplifier differentially amplifies the electrical intermediate signal and an inverse of the NRZ electrical data signal to generate an RZ electrical drive signal. The drive circuit drives the MZ modulator with the RZ electrical drive signal to generate the RZ optical data signal.

Abstract: A modulation system and a method for generating a return-to-zero (RZ) optical data signal are provided. The modulation system comprises a Mach-Zehnder (MZ) modulator and a drive circuit, which includes a logic XOR gate and a differential amplifier. The logic XOR gate applies a logic XOR operation to a non-return-to-zero (NRZ) electrical data signal and an inverse of an electrical clock signal to generate an electrical intermediate signal. The differential amplifier differentially amplifies the electrical intermediate signal and an inverse of the NRZ electrical data signal to generate an RZ electrical drive signal. The drive circuit drives the MZ modulator with the RZ electrical drive signal to generate the RZ optical data signal.