Title :
GaAs on quartz coplanar waveguide phase shifter
Author :
Islam, M.S. ; Tsao, A.J. ; Reddy, V.K. ; Neikirk, D.P.
Author_Institution :
Dept. of Electr. & Comput. Eng., Texas Univ., Austin, TX, USA
Abstract :
An optically controlled Schottky-contacted coplanar waveguide (CPW) phase shifter on a thin epitaxial GaAs film bonded to a quartz substrate has been fabricated using the epitaxial lift-off (ELO) technique. This allows the original semi-insulating GaAs substrate to be replaced by an optically transparent, low-dielectric-constant quartz substrate. A significant reduction in insertion loss and increase in phase shift was observed after lift-off. The ELO device allows the use of backside illumination for optical control, avoiding any metal shadowing effects, thus producing higher sensitivity to the optical signal. From 5 to 40 GHz, the ELO device gave an insertion loss of approximately -0.1 dB per degree of phase shift. At a backside illumination intensity of 0.65 mW/cm/sup 2/, a 1-cm-long device produced over 350 degrees of phase shift at 30 GHz.<>
Keywords :
III-V semiconductors; gallium arsenide; phase shifters; quartz; solid-state microwave devices; strip line components; 5 to 40 GHz; CPW; GaAs-SiO/sub 2/; SHF; Schottky contacts; backside illumination; coplanar waveguide; epitaxial lift-off; insertion loss; low-dielectric-constant; metal shadowing effects; optical control; optically transparent; phase shifter; quartz substrate; thin epitaxial GaAs film; Coplanar waveguides; Gallium arsenide; Insertion loss; Optical control; Optical films; Optical losses; Optical sensors; Optical waveguides; Phase shifters; Substrates;
Journal_Title :
Microwave and Guided Wave Letters, IEEE
