Stress field profiles and dielectric constant variations in In GaAsP/InP double heterostruct ures caused by a 110 nm thick W0.95Ni0.05 metal thin-film strain stripe are calculated. Both theoretical and experimental results demonstrate the form of the photoelastic waveguide structure in the InGaAsP/InP double heterostructures. For a 4bμm width W0.95Ni0.05 thin-film strain stripe, the difference between dielectric constants of the waveguide at the centre and the edge of the stripe is 9 × l0-2 - 2 × 10-2 in the depth range from 0.2 to 2 tm of the semiconductor. At a given depth, the width of the strain stripe for the optimal waveguide structure is determined. The maximal change of dielectric constant for the waveguide is an inverse proportion of the depth.