Bidirectional optical module

A bidirectional optical module comprising a light-emitting device which is formed of a semiconductor laser having a high linear-polarization performance and is 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 and a Faraday rotator disposed integrally on the reflection type polarizer or disposed in proximity thereto, 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.

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 wavelength splitting filter has a polarized-light separating function that the same polarized light as the transmitting signal light emitted from the light-emitting device passes through the filter but any polarized light perpendicular thereto does not pass through the filter;
• and 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 and a Faraday rotator disposed integrally on the reflection type polarizer or disposed in proximity thereto, which 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, and further comprises a cut filter provided on an optical path extending between the wavelength splitting filter and the light-receiving device, which cut filter permits the receiving signal light to pass through but cuts off the transmitting signal light.