Patent ID: 7734121

Claim:
A bidirectional optical module comprising a light-emitting device for emitting transmitting signal light therefrom, an optical fiber which the transmitting signal light emitted from the light-emitting device is made to enter, a light-receiving device which receiving signal light made to emerge from the optical fiber is made to enter, and a wavelength splitting filter provided at a position that fulfills a requirement that the filter is on an optical path extending between the light-emitting device and the optical fiber and on an optical path extending between the light-receiving device and the optical fiber; the transmitting signal light emitted from the light-emitting device being sent forward through the optical fiber, and the receiving signal light being sent backward through the optical fiber and received by the light-receiving device, which receiving signal light is of at least one wavelength different from the wavelength of the transmitting signal light; wherein; the bidirectional optical module comprises an optical device consisting essentially of a reflection type polarizer bonded to an end face of the optical fiber or disposed in proximity thereto, a Faraday rotator disposed integrally on the reflection type polarizer or disposed in proximity thereto and an absorption type polarizer disposed on an optical path extending between the light-emitting device and the wavelength splitting filter, and the reflection type polarizer has a wavelength dependency that it functions as a polarizer for the transmitting signal light but does not function as a polarizer for the receiving signal light.