Continuous-Wave InP-InGaAsP Microsquare Laser—A Comparison to Microdisk Laser

We demonstrate compact optically pumped microsquare cavity laser on InP-based multiple-quantum-wells material platform. Continuous-wave operation is achieved for microsquare cavity with footprint as small as 4 × 4 μm². Numerical mode analysis and experimental characterization of the microsquare laser are conducted, and the results are compared with the commonly used microdisk cavity laser fabricated on the same platform. The microsquare laser shows a lower lasing threshold and infers a higher differential efficiency than the microdisk counterpart. The microsquare cavity laser has also sufficiently high quality factor, and higher pumping injection efficiency due to the more evenly distributed field profile as compared to that of the microdisk. Experimental result also shows that the microsquare laser has better temperature stability than the microdisk. These results promise a potential alternative laser structure for on-chip light source applications.