Compact optical package made with planar structures

A device structure and system for connecting optical waveguides to optical transmit and receive components is described. The structure is made of two parts. The lower part contains active optoelectronic components, such as lasers and photodetectors, and optical lenses. The lower part can be assembled by steps of aligning and bonding planar components. The upper part contains optical waveguides and lenses for coupling light into and out of the waveguides. The top part is mechanically connected to the lower part to form a mechanically sound connection. The lens system provides some tolerance to mis-alignment between the top and bottom parts. The system has features that enable fiber optic components to operate and survive in harsh environments, particularly large temperature extremes.