Polarization-independent waveguide modulators using 1.57-mu m delta-strained InGaAs-InGaAsP quantum wells

We fabricated a multiple-quantum-well waveguide modulator incorporating two tensile S-strained layers within a nominally lattice matched well, that ac t to provide bias-independent Stark shift for both the light and heavy hole s. We report results for two waveguide geometries. One is a 2.3-mu m-wide r idge single-mode waveguide that was deep-etched 0.7 mu m below the active r egion to ensure that the confinement factor for both the TE; and TM modes a re nearly equal, The other was a broad-area (slab) multimode waveguide, For both geometries, transmission measurements indicate polarization insensiti vity within 3 dB for 2.5 V of reverse bias over the 1.600+/-1.630-mu m wave length range.