Abstract

Much attention has been paid recently to the transmission of information through one fiber via spectral multiplexing (wavelength-division multiplexing).^1,2 Some papers describe devices for channel demultiplexing^3,4; in particular, a demultiplexer with a planar diffused glass waveguide is known.⁵ In this device wavelength multiplexing takes place due to a concave grating attached to the end of the waveguide. Coupling between the multimode fiber and the planar waveguide is performed by direct junction of their end faces. However, the input N.A. of the diffused waveguide is different at various points on its end face due to graded refractive-index distribution vs depth. This decreases the extremely low coupling efficiency of the step-index fiber.

© 1981 Optical Society of America