Abstract: An optical isolator includes a first stage configured to refract a light ray applied in a forward direction into a first ray and a second ray. A second stage rotated 90° with respect to the first is configured to refract said first and second rays in a substantially parallel manner. The isolator is configured such that the first ray comprises an e-ray with respect to the first stage and an o-ray with respect to the second stage, and the second ray comprises an o-ray with respect to the first stage and an e-ray with respect to the second stage, thereby substantially reducing the effects of polarization mode dispersion.

Abstract: A collimating device having adjustable features that facilitate proper optical alignment of components positioned within the collimator is disclosed. In one embodiment, the collimating device includes a collimating portion including a collimating element, a core portion containing an optical device, and at least one adapter portion. An engagement surface on one end of the collimating portion is shaped to engage a corresponding engagement surface on one end of the adapter portion to form an adjustment point. An additional adjustment point is defined between another end of the adapter portion and an end of the core portion. These adjustment points enable the collimating portion to be maneuvered with respect to the core portion in order to align the collimating device. Minimal clearances between the adjustment point surfaces minimize the amount of adhesive needed to bond the collimator portion together after alignment, thereby producing a more stable and secure collimating device.

Abstract: A gain flattening and tap device. A gain flattening filter for use in fiber-optic communications includes a substrate. A GFF film is formed on a first surface of the substrate. An HR film is formed on a second surface of the substrate. The HR film is arranged to receive light from the GFF film and to reflect at least some of the light back through the GFF film. By passing the light through the GFF film multiple times, the effectiveness of the GFF film is multiplied. Further, by constructing the HR film to allow portions of the light to pass through, a tap may be implemented with the GFF.

Abstract: A polarization beam combiner/splitter (“PBCS”) for combining and splitting multiple channels of light beams simultaneously is disclosed. The PBCS includes a first fiber array, a second fiber array, and an optical core composed of a birefringent or other suitable material. The first fiber array includes a plurality of optical fiber pairs, while the second fiber array includes a corresponding plurality of optical fibers. The optical core is sized to modify light beams from any of the optical fibers of the first or second array. In a beam combining operation, multiple channels of polarized beams are emitted by the optical fiber pairs of the first fiber array and passed through the optical core, which combines the beams into dual-polarized combined light beams. The combined beams exit the optical core and are received by the second array of optical fibers. A similar beam splitting operation can be performed on multiple combined beams.

Abstract: A device functions as a polarization beam combiner and an isolator. When light is transmitted in a first propagation direction, a second beam is displaced towards a first beam. The second beam has a polarization orthogonal to the polarization of the first beam, and the second beam is substantially parallel to the first beam. The polarizations of the first and second beams are rotated by a same first amount in a first rotation direction and then rotated by the same first amount in a second opposite rotation direction. The first and second beams are combined by displacing the second beam towards the first beam. The combined beam is polarized along a first plane and second plane, which is orthogonal to the first plane. When light is transmitted in a second opposite propagation direction, the device is used to provide optical isolation.

Abstract: An optical polarization beam splitter comprises a first optical fiber having an end defining a first optical axis, a second optical fiber having an end defining a second optical axis, and a third optical fiber having an end defining a third optical axis parallel to and spaced apart from the second optical axis. A collimating lens is disposed along the first optical axis positioned to form a collimated optical beam from the first optical fiber. A focussing lens is disposed along a path of the collimated optical beam. A birefringent walk-off crystal has a first face adjacent to the focussing lens and a second face located at a focal plane of the focussing lens and in contact with the ends of the second and third optical fibers.

Abstract: A plug in communications module for achieving bidirectional communication along a single fiber-optic cable in a fiber-optic network. The plug in module is made such that it plugs directly into fiber-optic communication equipment of standard form factors. Bi-directional communication is achieved by using a low-cost circulator. The plug in module also has a receptacle that is used for attaching a patch cable between the fiber-optic network in the plug in module.

Abstract: Optical devices are disclosed, one example of which includes first and second polarization maintaining (“PM”) fibers. The first and second PM fibers in this example are disposed beside each other to form a grouping that includes a secondary axis defined by the first and second PM fibers. The first and second PM fibers are oriented such that a fast axis of the first PM fiber is non-parallel with respect to a fast axis of the second PM fiber. Finally, the optical device is configured so that each of the PM fibers maintains a distinct optical transmission path.

Abstract: Disclosed are optical circulators including a first beam displacer/combiner, a first nonreciprocal rotator, a first beam angle turner, a second beam angle turner, a second nonreciprocal rotator, and a second beam displacer/combiner, together with methods of using the optical circulators and telecommunications systems including the optical circulators.

Abstract: A method for improving the extinction ratio of a grouping of polarization maintaining (PM) fibers is disclosed, comprising: providing a plurality of PM fibers, the PM fibers each having corresponding principal axes; disposing the plurality of PM fibers as a grouping, the grouping having corresponding secondary axes; and aligning the plurality of PM fibers such that the corresponding principal axes of the plurality of the PM fiber and the secondary axes of the grouping intersect at a predetermined angle. Through the methods of the present invention, the extinction ratio of PM fibers may be improved.

Abstract: The present application teaches systems and techniques for reducing the polarization dependency of an optical component by combining the actions of a circulator and a polarization beam combiner to separate an optical signal into a plurality of orthogonally oriented polarization components; rotate at least one of the components so that the polarization orientation of the components are parallel; propagate the components through respective input ports of an optical component at substantially the same time; rotate at least one of a plurality of output components from the optical component so that the polarization orientation of the output components are orthogonal; and recombine the plurality of output components into an output optical signal.

Abstract: A gain flattening and tap device. A gain flattening filter for use in fiber-optic communications includes a substrate. A GFF film is formed on a first surface of the substrate. An HR film is formed on a second surface of the substrate. The HR film is arranged to receive light from the GFF film and to reflect at least some of the light back through the GFF film. By passing the light through the GFF film multiple times, the effectiveness of the GFF film is multiplied. Further, by constructing the HR film to allow portions of the light to pass through, a tap may be implemented with the GFF.

Abstract: An optical waveguide for use in amplifying light signals with an integrated gain equalization filter. The optical waveguide includes a gain section for amplifying light signals. The optical waveguide further includes an equalization filter to improve the uniformity of optical gain over a wavelength range for which the gain section is intended to provide amplification.

Abstract: A dual fiber optic amplifier uses a single pump source for two or more optical power amplifiers. The dual fiber optic amplifier includes a pump source that emits light, a pump splitter, a first optical power amplifier and a second optical power amplifier. The pump splitter splits the light emitted by the pump source into two or more portions. The first optical power amplifier includes an optical fiber input, an optical fiber output, and a doped fiber portion, wherein the first portion of light from the splitter is coupled into the optical fiber input of the first optical power amplifier. The second optical power amplifier includes an optical fiber input, an optical fiber output, and a doped fiber portion, wherein the second portion of light emitted from the splitter is coupled into the optical fiber input of the second optical power amplifier.

Abstract: An optical amplifier utilizes two or more doped fiber segments or portions to achieve a lower noise figure and a higher saturation power than would be possible using any one of the doped fiber segments. Each doped fiber portion may be considered to be a doped fiber optical amplifier, and has a different doping level than each of the other doped fiber portions. Each such doped fiber portion has distinct amplitude gain and noise characteristics relative to each of the other doped fiber potions. The two or more doped fiber portions are coupled to each other in series and most often in a predefined order based on their relative amplitude gain, noise and saturation power characteristics.

Abstract: A low-cost circulator used in fiber optic networks to accomplish bi-directional communication along a single fiber optic cable. The circulator has three ports, namely an input port, an output port and a bi-directional network port. The circulator core is constructed such that when light with a specific polarization is input into the input port, it is bent into the bi-directional network port where it can be propagated to the fiber optic network. Light input from the bi-directional network port can be any state of polarization, and it passes through the circulator core to the output port.

Abstract: An integrated optical polarization beam splitter/combiner and isolator (IPBC) is disclosed. In one disclosed aspect, the IPBC may comprise a first birefringent crystal optically configured to receive two rays incident at an angle, a rotator configured to rotate the rays received, and a second birefringent crystal positioned to receive the rays from the rotator. The IPBC may be configured to combine the rays in a forward direction, and isolate said two rays in a reverse direction.

Abstract: An integrated wavelength division multiplexer (WDM) coupler is provided which performs multiple optical coupling functions; the WDM coupler includes a first multi-fiber end optical termination and a second multi-fiber end optical termination; a filter is provided between the optical terminations which reflects certain light and passes certain light; the first and second optical terminations and the filter are arranged in relation to one another so as to perform at least one coupling function upon each of at least two separate non-bi-directional optical signals.

Abstract: An apparatus for optically circulating light beams between ports is disclosed, with a first port and third port positioned at a proximal end of the apparatus, a second port positioned at a distal end of the apparatus. The apparatus includes a first beam bender. The apparatus may additionally comprise end portions and imaging elements. The first and second end portions are positioned at either end of the apparatus to impart a propagation direction dependent polarization to the first light beam and the second light beam. The first imaging element and the second imaging element are positioned between the first and second end portions. The first imaging element bends the first light beam to a focal point between the first and the second imaging element. The second imaging element bends the second light beam to the focal point.

Abstract: Various embodiments of methods and systems of using TEC (Thermal-Diffusion Expanded Core) optical fiber to increase the power handling capabilities of an optical device are disclosed. In one embodiment, an optical device includes a TEC optical fiber that includes a first core. The diameter of the first core is larger at the end of the TEC optical fiber than it is in the unexpanded portion of the TEC optical fiber. The optical device also includes a focusing lens configured to focus light into the end of the TEC optical fiber so that a light spot created by the focused light on a surface of the end of the TEC optical fiber has a light spot diameter that is larger than the diameter of the first core in the unexpanded portion of the TEC optical fiber.