Improved photothermal deflection design of an integrated microbeam for application to an external-cavity tunable laser diode

摘要

This paper presents analytical results showing that the photothermal deflection of a microbeam greatly increases by employing an antireflection-coated bimorph structure. We expect this deflection to exceed half a wavelength, which is required for a tunable laser diode, by increasing the temperature by 100degreesC with an optical absorption rate above 98%. An antireflection coating of Au/Si3N4/Au on the Au and Si3N4 bimorph structure semiconductor microbeam provides enhanced deflection about 500 times greater than that of the solitary semiconductor microbeam at off-resonant frequencies. The designed microbeam monolithically integrated on gallium arsenide (GaAs at 0.83 mum wavelength) or indium phosphide (InP at 1.3 mum wavelength) platform will be used for a variable-length external-cavity edge-emitting tunable laser diode.