Patent ID: 7361884

Claim:
A polarization independent optical isolator, which: introduces receiver light inputted from an optical transmission path into a light receiving element; prevents reflected light of the receiver light from being inputted to the optical transmission path; and introduces transmitter light inputted from a light emitting element into the optical transmission path in a state where the transmitter light inputted from the light emitting element is not received in the light receiving element, the polarization independent optical isolator comprising: a first birefringent plate that divides the receiver light inputted from the optical transmission path into normal light and abnormal light to output the normal light and the abnormal light; a second birefringent plate that combines the normal light and the abnormal light which are divided by the first birefringent plate to output the combined light to the light receiving element; an optical rotation unit that is disposed between the first birefringent plate and the second birefringent plate, rotates the polarization direction of the normal light and the abnormal light which are outputted from the first birefringent plate by substantially 90° and outputs the rotated light, and outputs the reflected light of the receiver light which is divided into the normal light and the abnormal light by the second birefringent plate in a state where the polarization direction of the reflected light is not rotated; and a polarizing element that is disposed between the optical rotation unit and the second birefringent plate, allows one of the normal light and the abnormal light which are inputted from the optical rotation unit to pass therethrough and to be inputted to the second birefringent plate, and outputs the transmitter light inputted from the light emitting element to the optical rotation unit.