Wavelength tunable optical transmitter apparatus

A wavelength tunable optical transmitter apparatus, comprising

• a plurality of multi-longitudinal mode lasers, an optical splitter disposed on an output end of each of the multi-longitudinal mode lasers, a cyclic wavelength demultiplexer/multiplexer, and a reflector, wherein
• the optical splitter splits a signal output by each of the multi-longitudinal mode lasers into two parts, one part of the signal is connected to an input end of the cyclic wavelength demultiplexer/multiplexer, the other part of the signal output by each of the multi-longitudinal mode lasers is output, and an output end of the cyclic wavelength demultiplexer/multiplexer is connected to an input end of the reflector;
• the multi-longitudinal mode lasers output multi-longitudinal mode signals having a periodically repeated frequency interval, wherein a repetition period of the multi-longitudinal mode signals is Δfmode;
• the cyclic wavelength demultiplexer/multiplexer performs, by using filter windows of input ends, periodically repeated filtering on the multi-longitudinal mode signals input by the optical splitter, to obtain single frequency signals corresponding to the filter windows of the input ends of the cyclic wavelength demultiplexer/multiplexer;
• and the cyclic wavelength demultiplexer/multiplexer multiplexes the filtered single frequency signals from the input ends and outputs a multiplexed signal to the reflector by using the output end of the cyclic wavelength demultiplexer/multiplexer, wherein a repetition period of a center wavelength of the filter windows is Δfband, Δfmode is different from Δfband, and Δfmode and Δfband are not in an integer-multiple relationship;
• the reflector reflects the multiplexed signal back to the cyclic wavelength demultiplexer/multiplexer;
• after receiving the multiplexed signal reflected by the reflector, the cyclic wavelength demultiplexer/multiplexer demultiplexes the multiplexed signal reflected by the reflector to single frequency signals, separately determines filter windows of target input ends that correspond to the demultiplexed single frequency signals and the target input ends of the cyclic wavelength demultiplexer/multiplexer that correspond to the filter windows of the target input ends;
• and feeds back, by using the target input ends, the demultiplexed single frequency signals to the multi-longitudinal mode lasers connected to the target input ends;
• and
• the multi-longitudinal mode lasers lock on wavelengths of the demultiplexed single frequency signals fed back by the cyclic wavelength demultiplexer/multiplexer, and generate and output signals whose wavelengths are the same as the wavelengths of the demultiplexed single frequency signals fed back by the cyclic wavelength demultiplexer/multiplexer.