JPH05333243

PURPOSE:To funct a light emitting element operate even as a light receiving element, to curtail the number of components, and to make a module small in size and low in cost by using cylindrical lenses on end surfaces of a light emitting element package with a lens and a waveguide. CONSTITUTION:Light of wavelength lambda1 from the light emitting element is emitted by the light emitting element package 8 with the lens, passes through the cylindrical lens 9 fitted to the end surface of the multiplexing waveguide 3, propagated in the multiplexing waveguide 3 and a common waveguide 5, and then coupled with an optical fiber 7a. Light of wavelength lambda1 and lambda2 from the optical fiber 7a, on the other hand, is demultiplexed by a directional coupler 2 and light of lambda1 is propagated in the multiplexing waveguide 3 and cylindrical lens 9 and made incident on the light emitting element package 8 with the lens, so that the light emitting element functions as the light receiving element for the wavelength lambda1. Light of lambda2, on the other hand, is propagated from a demultiplexing waveguide 4 to an optical fiber 7b. The lens and light emitting element are previously integrated by an airtight sealing package 8, which is coupled with the cylindrical lens 9 by adjusting the position of the package.