Wavelength-division-multiplexing and -demultiplexing by using a substratemode grating pair

We present theoretical and experimental studies of a novel substrate-mode grating pair structure for wavelength-division-multiplexing/demultiplexing applications. Normally incident coupling and on-axis output imaging with this device provide easier alignment with coupled optical fibers. We have designed and fabricated wavelength-division-multiplexing devices that are implemented by polarization-insensitive high-efficiency (> 85%) substrate-mode holograms. Three-channel demultiplexing experiments have also been successfully demonstrated with the limited available wavelength range of our diode-laser system.