Cost-Effective Transceiver Based on an RSOA and a VCSEL for Flexible uDWDM Networks

A cost-effective transceiver for a 1-Gb/s full-duplex ultra-dense wavelength division multiplexing optical link is proposed for flexible metro-access and 5G networks. The transceiver is based on a vertical cavity surface emitting laser, which is used as the local oscillator for a heterodyne receiver and also feeds a phase-modulated reflective semiconductor optical amplifier (RSOA) transmitter. The modulation format used in the RSOA is a nonreturn-to-zero differential binary phase shift keying (DPSK) for the uplink, while the downlink is based on a Nyquist DPSK format. The central frequencies of the links are 2 GHz separated, and both links can be placed inside a 6.25-GHz frequency slot. The sensitivity of this transceiver is -43.5 dBm over a 50-km fiber.