VERTICAL-CAVITY DEVICES AS WAVELENGTH-SELECTIVE WAVE-GUIDES

We show that novel wavelength-sensitive devices can be fabricated by c oupling a semiconductor vertical cavity resonator to a low index waveg uide. The optical mode in the resonator propagates at an angle, and th e resonator resembles a high index waveguide. A taper in the thickness of the resonator allows different parts of the waveguide to operate a t different wavelengths. These structures are analyzed using both thin film equations and waveguide formalism. Concentrating on a waveguide demultiplexer, simple design equations are derived, and a demonstratio n device is fabricated for TE mode at 0.75 mum operation. Using AlGaAs /AlAs multilayers and a polymer top waveguide, the spectrometer exhibi ted a dispersion of 29 nm/cm, a wavelength resolution of better than 1 nm, and an intrinsic device efficiency of about 90%. A similar struct ure containing a light-emitting quantum well operated as a multiwavele ngth light source by modifying the spontaneous emission into the polym er waveguide.