Optical Multicarrier Generation Using Mach Zehnder Modulator

A low complexity optical frequency comb (OFC) is generated for WDM passive optical network. OFC is generated by a pair of Li-Nb Mach-Zehnder modulator (Li-Nb MZM) connected in cascaded form with external modulated laser (EML). The two Li-Nb MZM are driven by RF signal of 10 GHz. More than 60 flattened carriers are generated from OFC. After generating the Optical Frequency Comb (OFC), it is amplified by 10m long EDFA and the multi-carriers are separated into individual OFC tone using rectangular optical filter with 10 GHz bandwidth. Each OFC tone is modulated with 10Gbps QPSK based transmitter, then it is sent to 50km fiber using a WDM device. At the receiver side OFC channels are demultiplexed and demodulated individually. The proposed setup provides a cost-effective way to generate multiple carriers from a single source using less number of optical devices.