Abstract: An improved optical circulator transfers light from a first optical port to a second optical port, and from the second port to a third port. The circulator has non-reciprocal polarization rotators, birefringent beam splitters and combiners, and a polarization-dependent light bending device comprising two tapered birefringent plates. The light bending device compensates for an angle between a first light beam emanating from the first port and a second light beam propagating to the third port. The existence of this angle allows the first and third fibers to be coupled to the light beams using a single lens.

Abstract: A method of making short length fused fiber optical couplers and couplers made by the method. In a first step, fibers are fused by heating and pulled to form a taper section. Preferably, the fibers are twisted to assure good fusion. After pulling, in a second heating step, heat is applied to a portion of the taper section while the fibers are held stationary. The fibers are not pulled during the second heating step. The coupling ratio is monitored during the second heating step. The coupling ratio changes slowly during the second heating step and the heat is removed shortly before a desired coupling ratio is achieved. The residual heat continues to change the coupling until the desired coupling ratio is achieved. Couplers made according to the present method have a relatively short length. Couplers made according to the present method have a melted zone located in the taper section. The melted zone has a more rounded shape than the taper section due to surface tension.

Abstract: An improved optical circulator transfers light from a first optical port to a second optical port, and from the second port to a third port. The circulator has reciprocal and non-reciprocal polarization rotators, birefringent beam splitters and combiners, and a birefringent walk-off element as well as a polarization-dependent light bending device comprising two tapered birefringent plates. The light bending device compensates for an angle between a first light beam emanating from the first port and a second light beam propagating to the third port. The existence of this angle allows the first and third fibers to be coupled to the light beams using a single lens.

Abstract: An improved optical circulator device transfers light from a first optical fiber to a second optical fiber, and from the second fiber to a third optical fiber. The device comprises reciprocal and non-reciprocal polarization rotators, birefringent beam splitters and combiners, and a birefringent walk-off element. The invention also contains a polarization-dependent light bending device comprising two tapered birefringent plates. The light bending device compensates for an angle between a first light beam emanating from the first fiber and a second light beam exiting through the third fiber. The existence of this angle allows the first and third fibers to be coupled to the light beams using a single lens.