Wavelength division demultiplexer on a GaAs substrate

Abstract

Abstract Due to the material property restrictions of LiNbO3 and III-V compound material systems, a sizable portion of the research work on guided wave devices has been shifted to polymer-based materials. Low material dispersion, flexible material preparation process, unlimited device size, and cost effectiveness are the major factors that cannot be provided using conventional inorganic materials. By definition, a polymer matrix is formed by linking an array of monomers. Therefore, an infinite number of polymeric materials can be generated. The polymeric materials suitable for guided wave device research are those with desired optical and electro-optic properties. In this paper, a graded index (GRIN) polymer-waveguide-based twelve-channel single-mode wavelength division demultiplexer operating at 830, 840, 850, 860, 870, 880, 890, 900, 910, 920, 930, and 940 nm with diffraction angle varying from 20° to 65° is reported for the first time on a semi-insulating GaAs substrate. The GRIN characteristic of the polymer waveguide provides a universal guided wave device fabrication method that is not achievable through the conventional waveguide fabrication techniques. Minimization of the waveguide loss is achieved by an empirical profile tuning process that provides a GRIN layer as the cladding. A crosstalk figure of-20.5 dB and diffraction efficiency up to 55% were experimentally confirmed. The tunability of the waveguide refractive index allows the formation of a GRIN layer. As a result, these active and passive polymer-based guided wave devices can be realized on any substrate of interest. High quality waveguides (loss <0.1 dB/cm) have been made on glass, LiNbO3, fused silica, quartz, PC board, GaAs, Si, Al, Cu, Cr, Au, Kovar, BeO, Al2O3, and ALN.