Abstract: Two methods are presented in order to properly compensate the changes of the optical characteristics, which are caused by the optical path length change. First, a path length compensation method in which the additional optical path length, equivalent to the dicing kerf width of the substrate, is added onto the diced-to-be waveguide part of the AWG chip during the waveguide design process and fabrication process so that the compensated optical path length is maintained even after dicing. In addition, a position compensation method is provided in which an additional waveguide is added at the position shifted by a distance equivalent to the kerf width of the substrate such that the additional waveguide undergoes the minimized path length change after dicing is performed.

Abstract: The temperature dependency of center wavelength of AWG is compensated by adjusting optical input position by cutting interface between input slab waveguide of AWG and stripe waveguide circuit connected to input slab, followed by attaching lateral sliding rod which has larger Coefficient of Thermal Expansion than chip substrate. These cut-elements are passively re-aligned on the top surface of the alignment base substrate. The cut-element of AWG main body is adhered on alignment base substrate, and the cut-element of the strip waveguide circuit connected to the input slab is attached to the lateral sliding rod. The gap between the facets of re-aligned two cut-elements is maintained by inserting thin film followed by filling gap-fill material with no flowing nature to minimize degradation of optical characteristics and maintain free lateral movement between these two cut-elements.

Abstract: Two methods are presented in order to properly compensate the changes of the optical characteristics, which are caused by the optical path length change. First, a path length compensation method in which the additional optical path length, equivalent to the dicing kerf width of the substrate, is added onto the diced-to-be waveguide part of the AWG chip during the waveguide design process and fabrication process so that the compensated optical path length is maintained even after dicing. In addition, a position compensation method is provided in which an additional waveguide is added at the position shifted by a distance equivalent to the kerf width of the substrate such that the additional waveguide undergoes the minimized path length change after dicing is performed.

Abstract: Center wavelength of AWG is shifted due to the temperature variation. This invention described the method to compensate temperature dependency of center wavelength by adjusting optical input position passively by cutting the interface between the input slap waveguide (3) of AWG and the stripe waveguide circuit (1) connected to the input slab on a AWG chip, followed by attaching the lateral sliding rod (10) which has the larger CTE (Coefficient of Thermal Expansion) than AWG chip substrate (6). These cut-elements are passively re-aligned on the top surface of the alignment base substrate (7). At this process, the cut-element (6b) of AWG main body is firmly adhered on the alignment base substrate (7), and the cut-element (6a) of the stripe waveguide circuit (1) connected to the input slab is attached to the lateral sliding rod (10), which enables the position movement upon the temperature variation.

Abstract: The present invention provides an optical polyimide precursor for use in making a polyimide. The precursor is defined by the following formula: wherein X is Cl, Br, oxo-halide, or fully halogenated alkyl, and A is a divalent aromatic or halogenated aromatic moiety. The present invention provides a method of preparing a diamine compound for use as an optical polyimide precursor. The method includes the steps of dissolving 2-chloro-5-nitrobenzotrifluoride and a diol in N,N-dimethylacetamide to form a solution, adding potassium carbonate, tert-butylammonium chloride and copper powder to said solution and heating the resulting mixture, removing the copper, precipitating and recrystallizing a dinitro-compound resulting from heating the mixture, and dissolving the dinitro-compound and reducing the dinitro-compound to yield a diamine compound.

Abstract: Disclosed are an apparatus for and a method of measuring optical alignment conditions of optical fibers mounted to a V-groove array in an optical fiber block connected to the input or output terminals of an optical waveguide device.

Abstract: An optical waveguide including a core layer formed of a polymer, and a cladding layer placed in proximate to the core layer, the cladding layer being formed of a polymer having a refractive index smaller than the refractive index of the polymer for the core layer, wherein the polymers for the core and cladding layers are selected from the copolymers having the formula (1): where X is Y is and n is a mole fraction in the range of 0.05≦n<1.

Abstract: The present invention provides an optical polyimide compound defined by the following formula in an optical high polymer material: 1

Abstract: Disclosed is a method for formatting facets of an optical waveguide element.

Abstract: The present invention provides an optical polyimide compound defined by the following formula in an optical high polymer material: wherein X is Cl, Br, oxo-halide, or fully halogenated alkyl; A is a divalent aromatic or halogenated aromatic moiety; and Z is a tetravalent moiety which may be a partly or fully fluorinated aromatic ring, a partly or fully chlorinated aromatic ring, a partly or fully fluorinated cycloaliphatic group, a partly or fully chlorinated aliphatic group, or combinations thereof connected via hetero atoms.

Abstract: An optical waveguide chip includes an output waveguide connected to an optical fiber, an optical fiber array module, or another optical waveguide chip. The output waveguide has a coupling cross-section wider than the core of the optical fiber, the core of an optical fiber of the optical fiber array module, and the waveguide of the other optical waveguide, respectively. The cross-section width of the output waveguide of the optical waveguide chip gradually increases toward an end of the waveguide with a slant angle of 10° or less. Therefore, when the optical waveguide chip is connected to the optical fiber, the optical fiber array module, or the other optical waveguide chip during packaging of an optical waveguide device, an offset of the optical axis of about ±20% of the width of the waveguide guide is allowable.

Abstract: An optical power divider using a beam separator and a beam expander, and a fabrication method therefor. The optical power divider includes an input optical waveguide having an input port for receiving incident light, for guiding the light incident via the input port, a plurality of output optical waveguides having at least two output ports, for outputting the light incident via the input optical waveguide to the output ports, wherein the number of output optical waveguides is equal to that of the output ports, and a beam separator located at a branch area in which the light incident on the input optical waveguide diverges toward the output optical waveguides, the beam separator being made of a material having a refractive index lower than the core of the input and output optical waveguides, for separating the light to the output optical waveguides with a predetermined ratio. Therefore, the length of the optical power divider becomes short and insertion loss can be lowered.

Abstract: A mode shape converter, interposed between an input or output terminal of a function executing unit included in an optical device and an optical fiber and adapted to couple a mode of the optical fiber with a mode of the input or output terminal of the function executing unit, includes a substrate, a lower clad coated over the substrate, the lower clad having an etched portion in a desired region, a lower rib waveguide formed on the etched portion of the lower clad, a core. formed over both the lower rib waveguide and a non-etched portion of the lower clad, an upper rib waveguide formed on the core such that it is aligned with the lower rib waveguide, the upper rib waveguide having a desired shape, and an upper clad formed over both the upper rib waveguide and a portion of the core not covered with the upper rib waveguide.

Abstract: A thermo-optic switch using a small drive power while exhibiting a reduction in the coupling loss caused by the coupling to optical fibers and a switch speed of several hundred microseconds or less. A method for manufacturing the thermo-optic switch and a method for changing an optical line switching using the thermo-optic switch are also disclosed.

Abstract: A polyimide for optical communications, which is expressed by the formula (1) where R1 and R2 are independently selected from the group consisting of CF3, CCl3, unsubstituted aromatic ring group and halogenerated aromatic ring group; R3 and R4 are independently selected from the group consisting of Cl, F, I, Br, CF3, CCl3, unsubstituted aromatic ring group and halogenated aromatic ring group; and n is an integer from 1 to 39. The polyimides have a superior heat resistance, and can avoid the increase in optical absorption loss due to a refractive index increase and deterioration of adhesive and coating properties due to weak surface tension of a polyimide film. In addition, use of the polyimides as a material for a core layer of optical waveguides can expand the selection range of material for the cladding layer of the optical waveguide.

Abstract: A polyimide for optical communications, which is expressed by the formula (1), a method of preparing the same, and a method of forming multiple polyimide films using the polyimide, wherein the formula (1) is given by X1, X2, X3, A1, A2, B1, B2, B3, D1, D2, E1, E2, Y1, Y2, Y3, Y4, Y5, Y6, Y7, and Y8, are independently selected from the group consisting of hydrogen atom, halogen atom, alkyl group, halogenated alkyl group, aryl group and halogenated aryl group; Z is a simple chemical bond or selected from the group consisting of —O—, —CO—, —SO3—, —S—, —(T)m—, —(OT)m— and —(OTO)m—, wherein T is alkylene or arylene group substituted by at least one of halogen atom and halogenated alkyl group and m is an integer from 1 to 10; and n is an integer from 1 to 39.

Abstract: Disclosed is an optical waveguide device having a structure capable of allowing the optical waveguide device to be easily connected with an optical fiber array connector while allowing an easy separation thereof from the optical fiber array connector.

Abstract: The present invention provides an optical polyimide compound defined by the following formula in an optical high polymer material: 1

Abstract: An optical coupler and a method of manufacturing the same are provided. The optical coupler includes an input optical waveguide and N output optical waveguides, and divides an optical signal received from the input optical waveguide into N optical signals.

Abstract: In an optical intensity modulator, and a fabrication method thereof, the optical intensity modulator includes a substrate made of a predetermined material, an arc shaped optical waveguide formed on the substrate, and an electrode formed on the optical waveguide such that the electrode is in alignment with the optical waveguide, the refractive index of the optical waveguide being changed in accordance with an intensity of an electric field applied to the electrode, and an optical wave passing a predetermined location of the optical waveguide being radiated into the substrate due to the changed refractive index. Accordingly, a large modulation depth can be obtained from only a small refractive index variation by using the radiation loss characteristics of the arc shaped waveguide.