Abstract: An optical terminal using a capillary with a central opening or a bore of a selected cross section and having an insertion opening and a coupling opening. The optical terminal has a light-guiding element, e.g., a lens, positioned in front of the coupling opening. Optical fibers having adjusted cross sections along a fitting length are inserted into the bore such that they are wedged inside it, their tips are positioned at the coupling opening and their cores are offset by a specific distance or offset from the optical axis of the light guiding element. A number of fibers including optical and reinforcement fibers can be wedged in the bore in this manner to ensure a specific offset between the cores of the optical fibers and the optical axis. Precise control of the offset between the cores and the optical axis permits one to accurately control an output angle of light beams issuing from the optical fibers and exiting the optical terminal through the light guiding element.

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: 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.