Generation of optical frequency combs by Q-switching integrated multi-section semiconductor lasers

Abstract

In this work we perform a theoretical and simulation analysis of the behavior of an integrated four section distributed Bragg reflector semiconductor laser under optical injection and Q-switching operation. An electro-absorption modulator is introduced into the laser cavity to control the total losses and perform Q-switching. The simulations are done using a rate equation model. Q-switching operation produces very short and high power pulses. This, together with the use of optical injection, allows obtaining flat and broad optical frequency combs with up to 2100 optical lines within 10 dB (642 lines within 3 dB) at a repetition frequency of 100 MHz. The high chirp of the pulses is responsible for the broad spectra of these combs in comparison with gain switched combs, and the device structure allows fabrication in commercial foundries using standard building blocks.