Methods to enhance mode selectivity of higher-output vertical-cavity surface-emitting diode lasers

Abstract

Designing strategy to enhance mode selectivity of higher-output vertical-cavity surface-emitting diode lasers (VCSELs) is presented using the oxide-confined GaAs-based (GaIn)(NAs)/GaAs quantum-well VCSEL with two oxide apertures on both sides of its central active region as a typical example. A general strategy is to shift one aperture to the node position of the resonator standing wave where it is working as the electrical aperture only. Then diameters of both the apertures may be changed independently giving an additional degree of freedom for VCSEL designing. The comprehensive optical-electrical-thermal-gain self-consistent approach is used to simulate anticipated performance characteristics of the modified VCSEL. The single fundamental mode operation has been predicted in a large-size device with the 10-μm-diameter active region even for 80 K active-region temperature increase over the room ambient temperature. A similar radial waveguiding may be also produced in VCSELs with the aid of photonic crystals which have been found to create a very efficient discrimination mechanism for higher-order transverse modes. Therefore photonic-crystal confined VCSELs seem to be very promising structures in their future applications.