Abstract: A first exemplary aspect of the present invention is a wavelength-tunable optical transmitter including: a semiconductor substrate (101); a wavelength-tunable light source that is formed on the semiconductor substrate (101) and includes at least a first reflector (102) of a wavelength-tunable type and a gain region (104); a semiconductor optical modulator formed on the semiconductor substrate (101); a first semiconductor optical waveguide (105c) that is formed on the semiconductor substrate (101) and smoothly connected to the wavelength-tunable light source; a second semiconductor optical waveguide (105d) that is formed on the semiconductor substrate and smoothly connected to the semiconductor optical modulator; a waveguide coupling region (108) in which the first and second semiconductor optical waveguides are collinearly coupled with a length LC that is not equal to m/2 (m: integer) times a complete coupling length LC0; and a second reflector (113) formed at an end of the waveguide coupling region (108).

Abstract: The waveguide-type polarizer includes: a Z-cut lithium niobate substrate; an optical waveguide having a ridge structure and formed on the substrate; a low refractive index film formed with a thickness satisfying 0?n·t/??0.3742 (where n is a refractive index, t (?m) is the thickness of the film, and ? (?m) is the wavelength of a light wave) on the side of the ridge structure; and a high refractive index film formed with a thickness satisfying 0.089?n·/? on the low refractive index film. The width of the ridge structure is a ridge width where the distribution of ordinary light of the light waves propagated through the optical waveguide changes and the distribution of extraordinary light of the light waves does not change, the angle of the ridge structure is less than 90°, and the waveguide-type polarizer has a function of transmitting extraordinary light.

Abstract: An optical hybrid circuit includes a multimode interference coupler; a first 2:2 optical coupler; a second 2:2 optical coupler; a third 2:2 optical coupler; and a phase controlling region. The first 2:2 optical coupler, the second 2:2 optical coupler, and the third 2:2 optical coupler are coupled to one of the pair of first output channels, the pair of second output channels, the pair of third output channels, and the pair of fourth output channels of the multimode interference coupler. The phase controlling region is provided in one or both of each pair of at least two pairs of output channels from among three pairs of output channels to which the first 2:2 optical coupler, the second 2:2 optical coupler, and the third 2:2 optical coupler are coupled, respectively.

Abstract: An optical fiber that has a small bending loss can be securely prevented from being fractured due to accidental bending during installation or other operations. The optical fiber includes a core, a first cladding, a second cladding, and a third cladding. The relative refractive index difference ?1 of the core is in the range of 0.3% to 0.38%, the relative refractive index difference ?2 of the first cladding is equal to or smaller than 0%, and the relative refractive index difference ?3 of the second cladding is in the range of ?1.8% to ?0.5%. The inner radius r2 and the outer radius r3 of the second cladding satisfy the expression “0.4r2+10.5<r3<0.2r2+16”, and the inner radius r2 of the second cladding is equal to or greater than 8 ?m.

Abstract: Fiber optic assemblies including at least one multimode optical fiber that have improved performance are disclosed. In one embodiment, at least one connector is mounted upon and end of at least one multimode optical fiber and the assembly has an insertion loss of about 0.04 dB or less at a reference wavelength of 850 nanometers. Another embodiment is directed to a fiber optic assembly having a plurality of multimode optical fibers attached to a multifiber ferrule. The multifiber ferrule has a pair of guide pin bores having a nominal diameter, wherein the guide pin bores have a tolerance of ±0.0005 millimeters from a nominal diameter for improving performance.

Abstract: An optical connector according to an embodiment of the present invention comprises (a) a ferrule incorporating a short fiber; (b) a mechanical splice having a holding part and a fixing part, and adapted so that the fixing part mechanically fixes the short fiber extending from the ferrule held by the holding part, and an optical fiber in an optical cable to butt the short fiber; (c) an outer housing having a housing part in which the mechanical splice is located, and a pair of flexible arms located on both sides of the housing part, the pair of arms each being provided with a locking claw at a tip; and (d) a jacket fixture for fixing a cable jacket, the jacket fixture being coupled to the mechanical splice so that the cable jacket is inserted therein.

Abstract: The invention relates to a method and to an apparatus for compensating the polarization-dependent shift of the center frequency in an optical filter comprising an interferometer by way of compensating the birefringence in at least one waveguide of the interferometer, wherein at least one half-wave plate is arranged into the optical path of the interferometer and at least a section of the waveguide (16, 17) on the right and on the left of the half-wave plate (11) is brought to a pre-selectable temperature, and wherein at least one section on the right of the half-wave plate (11) is brought to a first temperature T1, and at least one section on the left of the half-wave plate (11) is brought to a second temperature T2.

Abstract: A microstructured fiber or photonic crystal fiber is described having a doped solid core region and a cladding region, holes being provided in the cladding region, the fiber having a low hybrid splice loss to conventional fiber as well as being able to be tightly bent due to the microstructured cladding. The cladding region can contain a plurality of holes surrounding and distanced from the core. These holes are preferably located symmetrically around the core and extend longitudinally along the length of fiber. The holes may be two or more D-shaped holes or truncated D-shaped holes arranged symmetrically around the care. In other embodiments, the holes comprise hole structures arranged symmetrically around the core in a ring. The holes may be arranged having the inner side facing the core formed from arcs of a circle, e.g. equal arcs of a circle. Between the arcs circular holes may be provided called capillaries, i.e. smaller holes.

Abstract: One embodiment includes communications module having a release slide and a boot. The release slide includes a main body, a plurality of arms, and a plurality of coupling structures. The arms extend from a first end of the main body. The coupling structures extend from a second end of the main body opposite the first end. The boot is disposed over the coupling structures of the release slide and defines a cavity configured to slidably receive a communications cable.

Abstract: A light trapping optical cover employing an optically transparent layer with a plurality of light deflecting elements. The transparent layer is configured for an unimpeded light passage through its body and has a broad light input surface and an opposing broad light output surface. The light deflecting elements deflect light incident into the transparent layer at a sufficiently high bend angle with respect to a surface normal and direct the deflected light toward a light harvesting device adjacent to the light output surface. The deflected light is retained by means of at least TIR in the system formed by the optical cover and the light harvesting device which allows for longer light propagation paths through the photoabsorptive layer of the device and for an improved light absorption. The optical cover may further employ a focusing array of light collectors being pairwise associated with the respective light deflecting elements.

Abstract: An example fiber optic cable includes an outer jacket having an elongated transverse cross-sectional profile defining a major axis and a minor axis. The transverse cross-sectional profile has a maximum width that extends along the major axis and a maximum thickness that extends along the minor axis. The maximum width of the transverse cross-sectional profile is longer than the maximum thickness of the transverse cross-sectional profile. The outer jacket also defines first and second separate passages that extend through the outer jacket along a lengthwise axis of the outer jacket. The second passage has a transverse cross-sectional profile that is elongated in an orientation extending along the major axis of the outer jacket. The fiber optic cable also includes a plurality of optical fibers positioned within the first passage a tensile strength member positioned within the second passage.

Abstract: A cutter tool for cutting at least one optical fiber arranged freely in a cavity of a telecommunications cable, the tool including a cutting element and a tube, the cutting element being adapted to form a snare around at least one optical fiber to be cut, the snare providing two strands of filament adapted to be introduced in the tube, and the tool enabling an optical fiber branch connection to be made over a long distance through an existing tapping window.

Abstract: A waveguide structure includes a supporting substrate and a waveguide having at least one guide layer with a refractive index n1. This layer comprises a zone of birefringence B which comprises voids provided in the thickness of the guide layer filled with a fluid or material having a refractive index n2. These are organized in at least two parallel rows, each row being in a plane perpendicular to the surface of the guide layer and parallel to the direction of propagation of the optical wave in the guide layer; each row extending over a distance equal to or greater than the wavelength of the optical wave; the width of the voids being ? 1/10th of the wavelength of the optical wave; each void within one row being at a distance from an adjacent void of ? 1/10th of the wavelength of the optical wave.

Abstract: The multicore fiber comprises 7 or more cores, wherein diameters of the adjacent cores differ from one another, wherein each of the cores performs single-mode propagation, wherein a relative refractive index difference of each of the cores is less than 1.4%, wherein a distance between the adjacent cores is less than 50 ?m, wherein, in a case where a transmission wavelength of each of the cores is ?, the distance between the adjacent cores is , a mode field diameter of each of the cores is MFD, and a theoretical cutoff wavelength of each of the cores is ?c, (/MFD)·(2?c/(?c+?))?3.95 is satisfied, and wherein a distance between the outer circumference of the coreand an outer circumference of the clad is 2.5 or higher times as long as the mode field diameter of each of the cores.

Abstract: Various embodiments include photonic bandgap fibers (PBGF). Some PBGF embodiments have a hollow core (HC) and may have a square lattice (SQL). In various embodiments, SQL PBGF can have a cladding region including 2-10 layers of air-holes. In various embodiments, an HC SQL PBGF can be configured to provide a relative wavelength transmission window ??/?c larger than about 0.35 and a minimum transmission loss in a range from about 70 dB/km to about 0.1 dB/km. In some embodiments, the HC SQL PBGF can be a polarization maintaining fiber. Methods of fabricating PBGF are also disclosed along with some examples of fabricated fibers. Various applications of PBGF are also described.

Abstract: A liquid crystal panel (2) includes a pair of substrates (10, 20) and a liquid crystal layer (30) sandwiched between the substrates (10, 20). At least one of the substrate (10, 20) is provided with combtooth electrodes (12, 13). The liquid crystal layer (30) is driven by a transverse electric field generated between the combtooth electrodes (12, 13). The liquid crystal layer (30) contains liquid crystal molecules (31) that align themselves perpendicularly to surfaces of the substrates when no electric field is applied. The liquid crystal panel 2 satisfies 0.33?S/(S+L)?0.64, where L is the width of each of the combtooth electrodes (12, 13) and S is the electrode interval.

Abstract: Various embodiments described include optical fiber designs and fabrication processes for ultra high numerical aperture optical fibers (UHNAF) having a numerical aperture (NA) of about 1. Various embodiments of UHNAF may have an NA greater than about 0.7, greater than about 0.8, greater than about 0.9, or greater than about 0.95. Embodiments of UHNAF may have a small core diameter and may have low transmission loss. Embodiments of UHNAF having a sufficiently small core diameter provide single mode operation. Some embodiments have a low V number, for example, less than 2.4 and large dispersion. Some embodiments of UHNAF have extremely large negative dispersion, for example, less than about ?300 ps/nm/km in some embodiments. Systems and apparatus using UHNAF are also disclosed.

Abstract: The invention relates to a device, system, and method for optimizing and altering electromagnetic frequency using Doppler shifts of electromagnetic radiation, and, in particular, optimizing frequency for application to photovoltaic devices and the like. The device comprises a crystal positioned in a channel undergoing a vibration, wherein an interaction between an incoming electromagnetic radiation and the vibration of the crystal optimizes a frequency of electromagnetic radiation.

Abstract: A Mach-Zehnder modulator has an optical splitting element splitting an input optical signal into two optical signals that are conveyed by two optical waveguide arms, and an optical combining element combining the two optical signals into an output optical signal. Two traveling wave electrodes (TWEs) carry an electrical modulation signal to induce a change in phase of these two optical signals, and include a number of pairs of modulation electrodes positioned adjacent to the waveguide arms. At least some of the electrodes in one waveguide arm have a different shape (e.g., length or width) than the electrodes in the other waveguide arm to alter the effectiveness of the electrodes in inducing a phase change in the two optical signals.

Abstract: The invention pertains to an optical connector assembly having an alignment mechanism for coupling two single-lens, multi-fiber optical connectors together. Particularly, each connector comprising a single lens through which the light from multiple fibers is expanded/focused for coupling to corresponding fibers in a mating connector. In one aspect of the invention, the alignment mechanism includes mating features extending from the fronts of the lenses having substantially longitudinal surfaces that meet and contact each other when the two connectors are coupled together in only one or a limited number of rotational orientations relative to each other to as to properly rotationally align the multiple fibers in the two mating connectors. This mechanism also helps align the two connectors with the optical axes of their lenses parallel to each other.