Design and cavity surface optimization of a new electro-absorption modulation laser

In order to solve the problems of slow response of the Selective Area Growth – Double Stack Active Laser-Electro-absorption Modulated Laser (SAG-DSAL-EML) in high frequency modulation and catastrophic optical damage (COD) caused by the sharp rise of cavity surface temperature when working at high temperature, a new type of SAG-DSAL-EML is designed, In this paper, the InGaAsP/InP material with 1.31 um iron-doped buried structure is used. The active region of the new SAG-DSAL-EML becomes mesa structure, and the iron-doped InP layer is grown on its two layers of epitaxy, and the cavity surface is coated with Al2O3 ,in the meantime the heat insulation structure is added. Firstly, ALDS and HFSS are used to analyze the laser and modulator of the designed iron-doped buried structure EML, the threshold current of SAG-DSAL laser is reduced by 13% , the lateral limiting ability of iron-doped buried structure is increased by 52% , the difference of far-field transverse and longitudinal angles is reduced by 40% , and the far-field divergence angle is smaller than the traditional ridge waveguide structure Compared with the traditional PNPN burying structure, the response band width of the iron-doped burying structure modulator is improved by about 24% at -3 dB, which meets the basic requirements of high-speed laser communication. Then, the solid heat transfer of the laser model is analyzed numerically and simulated by COMSOL. At 550K,the temperature of the cavity surface is simulated when there is no heat-insulating structure, no heat-insulating structure, no heat-insulating structure and no heat-insulating structure. The experimental results show that the laser with coating and heat insulation can effectively prevent COD at 550K and prolong its service life.