Patent ID: 6762879
Filing Date: 2004-07-13
Classification: G02B,Y10S

Abstract:
A closed loop optical circulator comprising:a first port; a last port; means for establishing a last optical path, the last optical path from the last port to the first port, the means for establishing including two pairs of complementary crystals, each crystal of a respective pair operable to transmit an optical signal of one polarization without deflection and deflect an optical signal of another polarization, the first pair of complementary crystals operable to transmit signals of a first polarization in a first direction and deflect optical signals of a second polarization in a second direction, the first pair of crystals operable to receive an optical signal from the last port and transmit the optical signal to the first port, the second pair of complementary crystals operable to transmit signals of a second polarization in a third direction and deflect optical signals of a first polarization in a fourth direction, the second pair of crystals disposed between the first pair of complementary crystals, said first and second directions defining a first plane, said third and fourth directions defining a second plane approximately orthogonal to said first plane; two pairs of complementary half wave plate rotators, each pair of complementary half wave plate rotators disposed between a crystal of the first pair and a crystal of the second pair of complementary crystals, each half wave plate rotator including a pair of half wave plate rotator groups where each group includes a half wave plate and a glass portion; and a halfwave plate and a Faraday rotator disposed between crystals of the second pair of complementary crystals.