Tunable Optical Waveguide Directional Coupler Filter

In future optical fiber communication systems it is likely that several optical carriers of different wavelength will be multiplexed onto a single fiber to increase its information carrying capacity. Recently wavelength multiplexors have been demonstrated which are compatible with multimode fibers. These multiplexors use graded index lenses and bulk frequency selective elements such as dielectric mirrors,1 prisms,2 and diffraction gratings.3 In this paper we demonstrate a monolithic integrated optical wavelength multiplexing filter using coupled optical waveguides.