Modulation Bandwidth Enhancement and Chirp Reduction in Integrated Optical Injection Locking DFB Laser

In this paper, a two-section integrated mutual injection distributed feedback (DFB) direct modulation laser based on reconstruction equivalent chirp (REC) technology is designed. By using the combined effect of optical injection locking and detuned-loading, the 3-dB modulation bandwidth of the mutual injection laser is increased to 28 GHz, and the side-mode suppression ratio (SMSR) is higher than 42 dB. The relative intensity noise (RIN) is reduced to below -145 dB/Hz and the chirp parameter is reduced from 2.61 to 1.34 under the stable locking state. Furthermore, the mutual injection laser also has good modulation linearity, in a wide frequency range with the 1-dB compression point larger than 16.46 dBm. The Spurious-free Dynamic Range (SFDR) is 94.21 dB•Hz
^(2/3)
at the 20 GHz modulation frequency.