Novel design procedure of broad-band multilayer antireflection coatings for optical and optoelectronic devices

A novel design procedure of broad-band multilayer antireflection (AR) coatings for optical and optoelectronic devices is proposed. The design algorithm is based on the optical admittance detuning, with the bandwidth of finite reflectivity as a new merit function. Coating structures consist of only two materials with nonquarter-wave thicknesses. Numerical mappings on the four-laver structure showed four optimizing regions where an optimized four-layer AR coating on 1.55 mu m GaInAs/AlGaInAs MQW semiconductor laser facet was predicted to have a broad bandwidth of 106 nm for a reflectivity of less than 10(-5). TiO2 and SiO2 were electron-beam (EB) evaporated to form the four-layer AR coating on glass and InP substrates with an ion-beam assist and a real time in situ optical thickness monitor and experimentally verify its broad-band performance.