Abstract: Photoelastic optoelectronic device is a novel planar device which is suitable for optoelectronic integrations. Deposition of 110 μm thick W_0.95Ni_0.05 metal thin film stripe on InGaAsP/InP heterostructure wafer is carried out using both of rf sputtering with the substrate under a negative dc bias of 120V and a photoresist lift-off technique. The photoelastic waveguides, which achieve the good lateral confinement of light in InGaAsP/InP heterostructures, are formed in semiconductor beneath a stripe of W_0.95Ni_0.05 thin film. The compression strain reduces about 10% in the metal thin film, and has a little changes for near-field optical mode after annealing at 250℃, 350℃, 450℃, and 600℃ for 30 min in 85% _N2 and 15% _H2 mixed gas. These experimental results have well confirmed the highly thermal stability of photoelastic waveguide structures formed by W_0.95Ni_0.05 metal thin film in InGaAsP/InP heterostructures.