Multi-band triangular frequency modulation signal generation based on gain-switched laser

A multi-band triangular frequency modulation signal generation method is proposed and verified by simulation and experiment. This is a simple photonics method based on distributed feedback gain switching states of semiconductor lasers without the need for complex external modulators. The carrier frequency and bandwidth of the generated triangular frequency modulation signal are N times that of the fundamental signal (N is the number of comb lines). By tuning the bandwidth and duration of the fundamental signal, the product of the number of frequency bands and the time bandwidth (TBWP) of the generated signal can be easily adjusted. The autocorrelation results of the generated waveform are also given. The triangular frequency modulation signals of six bands from S-band to K-band are realized, and have different chirp rates. The maximum TBWP reaches 24 000, and the corresponding range resolution reaches 6.3 cm.