Low Cost Tapered Couplers Using Micromachining Techniques

Adiabatic tapered optical couplers or mode expanders have been developed recently for high efficiency coupling between diode lasers and optical fibers. In this SBIR program, Foster-Miller proposes a novel low-cost coupler that achieves high efficiency via a 2-axis tapered design. The tapered structures, formed in semiconductor substrates are integrated with polymeric waveguide media in constructing the couplers. Our approach, which realizes a vertical and horizontal taper uses concepts of micromachining, widely used today in passive alignment of fiber-optic components. A significant feature of our approach is the ease of fabrication, high efficiency, low loss (< 1db) and compatibility with existing silicon based technologies. The proposed design will be fabricated using a very high resolution direct laser write system developed a Foster-Miller. Using this system 2-axis tapered couplers with linear and non-linear tapers will be directly etched onto silicon substrates. The Phase I research will result in several test vehicles whose characteristics will be tested at a major national laboratory specializing in test and standardization of passive optical components. In Phase II, Foster-Miller will scale the design for multi-chip module with integrated diode lasers and fiber connectors.