Peter De Dobbelaere

Fabrication of high-radiance LEDs by epitaxial lift-off

Fully processed A1GaAs/GaAs LEDs were lifted off their GaAs substrates and grafted to various host substrates. Due to a metallic back reflector beneath the epitaxial structure, the LED output power was 2 to 3 times increased compared to LEDs still on a GaAs substrate. Output power and spectral responses were significantly influenced by the thermal properties of the host material.

Optical free-space board-to-board interconnect: options for optical pathways

The optical free-space interconnect is becoming increasingly important because of its high intrinsic density and routing capabilities. This paper deals with a free-space board-to-board interconnect, based on light-emitting diode arrays as sources. The design of the optical pathway is discussed, and some design rules and simulation results are presented. Two basic options (a lens array and a single lens) are evaluated, and their performance, in terms of power transfer, cross talk, and uniformity, are analyzed.

Micromachined photodiode submount with integrated mirror for efficient out-of-plane coupling to planar polymeric waveguide circuits.

We report on a hybrid coupling concept which allows high-density integration of top illuminated photodetector arrays with planar polymeric waveguide circuits by means of a micromachined submount with an integrated mirror. The etching of a complementary alignment structure in the polymeric layer stack allows passive assembly. The fabrication process of the submount structure is described, focusing on the optimization of the mirroring facet surface quality in order to reduce the effect of topographic scattering. A prototype 8-channel detector module integrated with a straight polymeric waveguide array exhibited an average coupling efficiency of -6.1 dB and a cross-talk value of -21.3 dB between adjacent channels at 1300 nm.

Integration technology for light-source arrays with polymeric optical waveguide arrays

The integration of efficient semiconductor lightsources with low-loss functional optical waveguide devices is one of the major problems in integrated optics. In this paper we present a novel integration scheme based on the epitaxial lift-off technique for the integration of a laser diode array with an array of polymeric waveguides. This method shows a number of advantages with respect to previously reported solutions. The presented quasi-monolithic integration of laser diodes with polymeric waveguides might lead to important applications in areas such as optical interconnections and optical communications.

Reliability and Environmental Stability of Polymer based Solid State Optical Switches

The development of reliable and environmentally stable photonic space switches based on the BeamBoxaTM Solid State Optical Switch technology is described. The realization of a robust temperature stable (-40°C to 75°C) fiber pigtail attachment joint is presented.

InGaAs/AlGaAs vertical optical modulators and sources on a transparent GaAs substrate

InGaAs/AlGaAs Strained Layer Superlattices (SLS) have been grown using the MOVPE technique. These layers were characterized by X-ray, photoluminescence, photocurrent and transmission measurements. With this material optical modulators and LEDs were made working at a wavelength for which the GaAs substrate is transparent. Reverse biasing the modulator resulted in a large absorption shift in the photocurrent spectra due to the Quantum Confined Stark Effect (QCSE) on the quantum wells. An InGaAs/AlGaAs SLS compared favorably with similar InGaAs/GaAs SLSs. A back-side emitting LED, with an InGaAs SQW as the active layer, gave a maximal output power of about 8 micro-W/mA/Sr.