Nonlinear distortion reduction in transverse mode stabilized oxide-confined VCSELs

Fundamental mode operation has been achieved in a large area oxide-confined vertical-cavity surface-emitting laser (VCSEL) by etching a shallow surface relief in the top mirror. The nonlinear distortion during analog modulation has been measured and compared to the distortion in a planar multimode VCSEL. The distortion was quantified by conventional two-tone measurements from which the spurious free dynamic range was determined. Several decibels improvement in dynamic range was observed in the low frequency range (0.1-2 GHz) for the single-mode VCSEL. This is primarily due to a higher relaxation frequency and an absence of mode competition and mode partition noise in the single-mode VCSEL, indicating the advantages of using single-mode VCSELs for high-performance analog modulation.