Abstract
The invention provides an optical circulator that comprises three ports with the property that light entered through the nth port is output through the (n+1)th port. It can be applied to optical fiber transmission of optical signals. It uses a reflector to make a two-core fiber collimator to be a first port and a second port of the optical circulator so as to minimize the optical circulator volume and to simplify the assembly procedure. A reciprocal crystal and a non-reciprocal crystal are combined to form an optical polarization controller to conquer such technical problems as the conjugate angle of the two-core collimator and the minimal polarization mode dispersion. In particular, the corresponding relation between the Faraday rotator and the birefringent crystal optical axis can be utilized to remove half-wave plates used in ordinary optical circulators, thus lowering manufacturing costs and complexities.