MODIFICATION OF REFRACTIVE-INDEX OF GAAS BY ION-IMPLANTATION OF OXYGEN

The modification of the refractive index of GaAs by direct oxygen ion implantation has been investigated. It is observed that the refractive index increases in the as-implanted GaAs by about 0.1 to 0.2, at the wavelengths of 633 and 1310 nm. The increase in refractive index resul ts from the formation of an amorphous layer in the implanted region an d is independent of the type of GaAs substrate. Rapid thermal annealin g at 600-degrees-C reduces the refractive index almost to its original value before implantation. This is the first time that such measureme nts are made at the important wavelength of 1310 nm used in most exist ing optical communication systems. The results suggest that practical waveguides can be fabricated on GaAs if the implanted layer thickness can exceed approximately a micrometer.