Abstract: Methods and structures for reducing and/or eliminating moisture penetration in an optical package. The optical package may include (1) a layer of inorganic material placed over the points of the optical package susceptible moisture penetration of the optical package; (2) a portion of hygroscopic material placed over the points of the optical package susceptible to moisture penetration; (3) a layer of hygroscopic material placed on the interior surface of the optical package; and/or (4) a layer of hydrophobic material coated on the optical surfaces of the optical package.

Abstract: An isolator is disclosed that features a single birefringent correction element. The correction element is configured to eliminate differential group delay and walk-off simultaneously.

Abstract: An optical pumping module for use in optical amplifiers in fiber-optic communication. The pump module integrates laser diodes and a polarization beam combiner (PBC). The laser diodes and PBC may be attached to a substrate. The laser diodes may be formed onto the substrate either monolithically or by attaching discrete components to the substrate. The PBC may include isolation to prevent reflections back into the laser diodes.

Abstract: A plug in communications module for achieving bi-directional 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: 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: This disclosure concerns low insertion loss optical circulators. In one example, the optical circulator has four ports and includes a polarization dividing and combining element that is positioned adjacent the first and fourth ports and is adapted to divide a beam of light into two beams of light of orthogonal polarizations. The polarization dividing and combining element is also adapted to combine two beams of light of orthogonal polarizations into one beam of light. The optical circulator also includes a Faraday rotator positioned near the second port, and a Faraday rotator positioned near the third port. The Faraday rotator rotates beams of light before or after the pass through the polarization dividing and combining elements.

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: Methods and structures for reducing and/or eliminating moisture penetration in an optical package. The optical package may include (1) a layer of inorganic material placed over the points of the optical package susceptible moisture penetration of the optical package; (2) a portion of hygroscopic material placed over the points of the optical package susceptible to moisture penetration; (3) a layer of hygroscopic material placed on the interior surface of the optical package; and/or (4) a layer of hydrophobic material coated on the optical surfaces of the optical package.

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: 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 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 optical device is described that may be used to split a beam of light into two or more components of light or combine two or more components of light into a combined beam of light. The optical device may also provide isolation (i.e., inhibit optical feedback) in the reverse direction. The beam of light may be split into two or more polarized components of light. Similarly, the two or more components of light that are combined may be polarized. The optical device may be coupled to optical fibers for both input and output of the beam of light or the two or more components of light.

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: An isolator is disclosed that features a single birefringent correction element. The correction element is configured to eliminate differential group delay and walk-off simultaneously.