AN INTEGRATED OPTICAL PACKAGE FOR COUPLING OPTICAL FIBERS TO DEVICES WITH ASYMMETRIC LIGHT BEAMS

This invention embodies an integrated optical package including an optical component having an asymmetric modal output, and a lens integrated with the component for coupling to another component having a large modal area. The coupling is achieved by the use a tapered waveguide section (12). This section may be referred to as Polymeric Elongated Waveguide Emulating (PEWE) lens. In the exemplary embodiment the first optical component is a modulator (11), and the other optical component is an optical fiber (13). A facet of the modulator is etched by reactive ion etching (RIE) which allows integration of the PEWE lens on a common substrate (14). The lens is manufactured using a polymer film on a dielectric cladding layer. The fabrication relies on the remelt and reflow properties of polymer films to provide a smooth adiabatic mode contraction from a circular (optical fiber) mode ( APPROX 6 mu m in diameter) to a semiconductor mode ( APPROX 1 mu m) over a length of 250 mu m. The PEWE lens permits coupling with an insertion loss of 0.5 dB and 80 percent coupling efficiency, even though the lens is butt-coupled to a fiber without any external lens. The PEWE lens allows the realization of better than 80 percent direct fiber butt-coupling efficiencies to semiconductor lasers, photodetectors, optical modulators, switches and amplifiers with a simultaneous order of magnitude relaxation of the alignment tolerances typically needed for the coupling of semiconductor devices with single-mode fibers.