A WDM/TDM Access Network Based on Broad T-Band Wavelength Resource Using Quantum Dot Semiconductor Devices

A wavelength-division multiplexing/time-division multiplexing (WDM/TDM) network exploiting the broad wavelength range of T-band (1000–1260 nm) is proposed. The network is based on different wavebands of downlink and uplink channels, with each transmitter consisting of a wavelength tunable laser utilized for more than one user through wavelength tuning. The downlink section of the network also introduces interconnecting optical lines and semiconductor optical amplifiers (SOAs), pairing up each of the downlink wavebands to provide structural redundancy by allowing transmitters to be shared between the paired wavebands through TDM. Quantum dot (QD)-based wavelength tunable lasers and SOAs were fabricated for a preliminary demonstration experiment. Error-free transmission with less than 1 dB of power penalty was obtained for a wavelength range of 24.2 nm (5.6 THz). The QD-SOAs exhibited a decent rise and fall time, as well as extinction ratios throughout the wavelength range, which enable it to be used as path switches.