Relative intensity noise in high-speed hybrid square-rectangular lasers

Relative intensity noise (RIN) and high-speed modulation characteristics are investigated for an AlGaInAs/InP hybrid square-rectangular laser (HSRL) with square side length, rectangular length, and width of 15,300, and 2 mu m, respectively. Single-mode operation with side-mode suppression larger than 40 dB has been realized for the HSRL over wide variation of the injection currents. In addition, the HSRL exhibits a 3 dB modulation bandwidth of 15.5 GHz, and an RIN nearly approaches standard quantum shot-noise limit 2hv/P = -164 dB/Hz at high bias currents due to the strong mode selection of the square microcavity. With the increase of the DC bias current of the Fabry-Perot section, significantly enhanced modulation bandwidth and decreased RIN are observed. Furthermore, intrinsic parameters such as resonance frequency, damping factor, and modified Schawlow-Townes linewidth are extracted from the noise spectra. (c) 2018 Chinese Laser Press