Abstract
Titanium dioxide (TiO ) dielectric material was deposited as ~/4 antireflections (AR) coating 2 on one facet of GaAs-GaxAl1-xAs double hetero-structure (DH) laser. Single layer ~ /4 AR coating was achieved by successive deposition of TiO2 thin films in vacuum in small steps by thermal evaporation technique, while measuring the threshold current after each coating outside the vacuum. Threshold current, reflectivity and far-field patterns of laser show the significant influence of AR coatings on light output characteristics. Internal loss parameter and the gain coefficient for the DH laser were determined from threshold current under the case temperature of the laser.