Optimization of omnidirectional reflector for infrared-emitting diodes

A simulation method of weighting reflectance for omnidirectional reflectors utilizing a silicon dioxide (SiO2) layer used in emitting diodes and its implementation is reported. The approach is based on the well-known transfer-matrix method and a successive weighting of reflectance values by wavelength, angle of incidence and polarization to determine an optimum SiO2 layer thickness. Simulation results are reported for different wavelength types of infrared-emitting diodes (IREDs). High reflectance is achieved for SiO2 thicknesses of 200 to 250 nm. Validation is conducted by experimental light output power (LOP) data of an 890 nm type IRED and LOP-reflectance dependency is modeled.