Abstract: An external mode size transformer includes a waveguide having an input section, an output section, and a tapered section disposed between the input and output sections. The cross sections between the input and output sections of the waveguide can vary smoothly throughout the length of the waveguide, similar to a waveguide shaped like a boat hull. By positioning the external mode size transformer between optical devices, coupling between optical devices is substantially improved compared to that of direct coupling. For example, by positioning the external mode size transformer between a laser and an optical fiber, laser to fiber coupling is significantly improved compared to that of direct coupling between these optical devices. The present invention can include a manufacturing method that employs multiple masks with predetermined shapes to fabricate the sections of the waveguide within a planar substrate via an exemplary ion exchange process.

Abstract: An optical add/drop multiplexing (OADM) device can increase the number of information channels carried by an optical waveguide by utilizing different wavelength regions of light. In other words, each information channel can be assigned a specific wavelength region of light The OADM device can add additional virtual optical waveguides equal to the number of wavelength regions of light that can be efficiently propagated along a single optical waveguide. The OADM device can utilize conventional diode laser technology for adding information channels at predefined wavelength regions into an optical network. The OADM device can stabilize the output wavelength region of a conventional laser diode to any specific wavelength region with minimal hardware or structural modifications. By utilizing off the shelf hardware, the OADM device can lower manufacturing costs while providing an ample supply of spare parts.