Optical multiplexer and demultiplexer module including multiplexing and

Abstract

A compact size optical multiplexer and demultiplexer module. The optical multiplexer and demultiplexer module includes a multiplexing and demultiplexing film disposed on an end surface of a waveguide substrate, having an optical waveguide formed thereon, on which surface an input and output end of the optical waveguide appears. The multiplexing and demultiplexing film transmits a light beam of wavelength .lambda..sub.1 and reflects a light beam of wavelength .lambda..sub.2. A first optical fiber is disposed such that a light beam with the wavelength .lambda..sub.1 propagated therethrough is coupled to the input and output end of the waveguide substrate after being transmitted through the multiplexing and demultiplexing film and the second optical fiber is disposed such that a light beam with the wavelength .lambda..sub.2 propagated therethrough is coupled to the first optical fiber after being reflected by the multiplexing and demultiplexing film. A light beam with the wavelength .lambda..sub.1 from the first optical fiber is transmitted through the multiplexing and demultiplexing film and sent to a photodiode and a light beam with the wavelength .lambda..sub.1 from a laser diode is transmitted through the multiplexing and demultiplexing film and sent to the first optical fiber. A light beam with the wavelength .lambda..sub.2 from the second optical fiber is reflected by the multiplexing and demultiplexing film and sent to the first optical fiber.