Abstract: A resin coating device for coating a surface of a glass fiber, includes: a point having a point hole; a die disposed directly below the point and including a first alignment portion, a second alignment portion, and a first die hole; and a first resin supply path. The second alignment portion is disposed below the first alignment portion. The first alignment portion includes a first diameter-reduced portion, and a first land portion disposed, connected to the first diameter-reduced portion, and having a constant diameter in the traveling direction. The second alignment portion includes a second diameter-reduced portion, and a second land portion, connected to the second diameter-reduced portion, and having a constant diameter in the traveling direction. The first diameter-reduced portion, the first land portion, the second diameter-reduced portion, and the second land portion are each a part of the first die hole.

Abstract: A light device according to one embodiment includes a light source and an optical lens having an incidence plane extending in both a first axis and a second axis intersecting the first axis and an emission plane extending in both the first axis and the second axis. The optical lens converts incident light emitted from the light source and incident on the incidence plane into parallel light and emits the parallel light from the emission plane, and the incidence plane has a convex portion provided in a first direction in which the first axis extends and a concave portion provided in a second direction in which the second axis extends.

Abstract: A reflection unit of this disclosure is a reflection unit installed in a wireless transmission path between a first wireless device configured to at least transmit a wireless communication signal and a second wireless device configured to at least receive the wireless communication signal, in order to change a direction of the wireless transmission path. The reflection unit includes a plurality of reflectors configured to reflect the wireless communication signal. The plurality of reflectors include at least one reflectarray reflector.

Abstract: One embodiment of the present disclosure relates to an SFG (slanted fiber grating) that can easily realize a high-performance gain equalizer. The SFG includes an optical fiber comprised of silica-based glass and including a core, a first cladding containing a photosensitive material, and a second cladding. A specific section between two different points arranged along a fiber axis in the optical fiber is configured with a first region, a pair of second regions, and a third region. The first region includes a slanted Bragg grating provided in a region as the first cladding. The pair of second regions are arranged to sandwich the first region. The third region is disposed to sandwich both the first region and the pair of second regions. An MFD at a wavelength of 1.55 ?m in the third region is smaller than an MFD at a wavelength of 1.55 ?m in the first region.

Abstract: An optical fiber preform including a glass material and a refractive index adjusting additive is disclosed. This preform has striae due to difference in concentration of the additive and the striae have concentric refractive index periodicity in at least a part thereof from a radial center of the preform to an outer periphery thereof. The respective striae pitches each indicating a period of the refractive index periodicity increase from the center of the preform to the outer periphery thereof.

Abstract: Disclosed is an optical device including a first lens and a second lens. The first lens of the optical device is joined to an end surface of an optical waveguide of an optical element to emit light emitted from the optical element. The second lens is optically coupled with the first lens to convert the light emitted from the first lens into collimated light.

Abstract: One embodiment of the present disclosure relates to an SFG (slanted fiber grating) that can easily realize a high-performance gain equalizer. The SFG includes an optical fiber comprised of silica-based glass and including a core, a first cladding containing a photosensitive material, and a second cladding. A specific section between two different points arranged along a fiber axis in the optical fiber is configured with a first region, a pair of second regions, and a third region. The first region includes a slanted Bragg grating provided in a region as the first cladding. The pair of second regions are arranged to sandwich the first region. The third region is disposed to sandwich both the first region and the pair of second regions. An MFD at a wavelength of 1.55 ?m in the third region is smaller than an MFD at a wavelength of 1.55 ?m in the first region.

Abstract: An optical fiber is made of silica-based glass and includes a core, a first cladding that surrounds the core and that has a refractive index lower than a refractive index of the core; and a second cladding that surrounds the first cladding and that has a refractive index lower than the refractive index of the core and higher than the refractive index of the first cladding. At least a part of the first cladding contains a photosensitive material whose refractive index increases by irradiation with light having a specific wavelength. A difference ?n between a refractive index of a portion of the first cladding, the portion being nearest to the core, and the refractive index of the core is in a range of 0.25% to 0.30%. The radius ra of the core is larger than 4.3 ?m and smaller than or equal to 5.0 ?m.

Abstract: An optical fiber preform including a glass material and a refractive index adjusting additive is disclosed. This preform has striae due to difference in concentration of the additive and the striae have concentric refractive index periodicity in at least a part thereof from a radial center of the preform to an outer periphery thereof. The respective striae pitches each indicating a period of the refractive index periodicity increase from the center of the preform to the outer periphery thereof.

Abstract: The present embodiment relates to an optical device or the like that is high in non-linearity and resistance to UV light and includes a structure allowing stable wavelength conversion. The optical device is comprised of glass containing SiO2 and comprises a repetitive structure including first sections being crystallized regions in which a radial polarization-ordered structure is formed and second sections being non-crystallized regions alternately arranged along a center axis extending from a center of a light-incidence end face toward a center of a light-emission end face.

Abstract: An optical module with a laser diode (LD) without any temperature control and an optical fiber that is coupled with the LD through the two lens system is disclosed. The two lens system first converts laser beam into collimated beam and second concentrates the collimated beam onto the optical fiber. A beam splitter is disposed between the lenses and splits the collimated beam toward a photodiode (PD). The PD, which receives the split collimated beam in a back surface thereof, provides an anti-reflection film in the back surface. The anti-reflection film eliminates multi reflections occurred within the PD.

Abstract: An optical module with a laser diode (LD) without any temperature control and an optical fiber that is coupled with the LD through the two lens system is disclosed. The two lens system first converts laser beam into collimated beam and second concentrates the collimated beam onto the optical fiber. A beam splitter is disposed between the lenses and splits the collimated beam toward a photodiode (PD). The PD, which receives the split collimated beam in a back surface thereof, provides an anti-reflection film in the back surface. The anti-reflection film eliminates multi reflections occurred within the PD.

Abstract: An optical fiber is made of silica-based glass and includes a core, a first cladding that surrounds the core and that has a refractive index lower than a refractive index of the core; and a second cladding that surrounds the first cladding and that has a refractive index lower than the refractive index of the core and higher than the refractive index of the first cladding. At least a part of the first cladding contains a photosensitive material whose refractive index increases by irradiation with light having a specific wavelength. A difference ?n between a refractive index of a portion of the first cladding, the portion being nearest to the core, and the refractive index of the core is in a range of 0.25% to 0.30%. The radius ra of the core is larger than 4.3 ?m and smaller than or equal to 5.0 ?m.

Abstract: An optical coupling system to couple a collimated beam with a waveguide made of semiconductor materials is disclosed. The waveguide is implemented in an optical modulator and/or an optical hybrid, and has a core with a restricted cross section because of the enhanced refractive index of the semiconductor materials. The collimated beam is focused on the core by the two-lens system including first and second lenses. The first lens, having a focal length shorter than a focal length of the second lens, is first aligned with the core, then, the second lens is aligned with the core as compensating deviations of the first lens induced during the fixation thereof.

Abstract: An optical coupling system to couple a collimated beam with a waveguide made of semiconductor materials is disclosed. The waveguide is implemented in an optical modulator and/or an optical hybrid, and has a core with a restricted cross section because of the enhanced refractive index of the semiconductor materials. The collimated beam is focused on the core by the two-lens system including first and second lenses. The first lens, having a focal length shorter than a focal length of the second lens, is first aligned with the core, then, the second lens is aligned with the core as compensating deviations of the first lens induced during the fixation thereof.

Abstract: An optical coupling system to couple a collimated beam with a waveguide made of semiconductor materials is disclosed. The waveguide is implemented in an optical modulator and/or an optical hybrid, and has a core with a restricted cross section because of the enhanced refractive index of the semiconductor materials. The collimated beam is focused on the core by the two-lens system including first and second lenses. The first lens, having a focal length shorter than a focal length of the second lens, is first aligned with the core, then, the second lens is aligned with the core as compensating deviations of the first lens induced during the fixation thereof.

Abstract: An embodiment of the invention relates to a GI-MMF with a structure for achieving widening of bandwidth in a wider wavelength range and improving manufacturing easiness of a refractive index profile in a core. In an example of the GI-MMF, a whole region of the core is doped with Ge and a part of the core is doped with P. Namely, the Ge-doped region coincides with the whole region of the core and the Ge-doped region is comprised of a partially P-doped region doped with Ge and P; and a P-undoped region doped with Ge but not intentionally doped with P.

Abstract: A quantum cascade laser includes a substrate having a principal surface; a laser body region disposed on the principal surface, the laser body region including a semiconductor laminate structure having an end facet, the laser body region having a waveguide structure extending along a waveguide axis; and a distributed Bragg reflection region disposed on the principal surface, the distributed Bragg reflection region including low and high refractive index portions that are alternately arranged in a direction of the waveguide axis. The end facet of the semiconductor laminate structure is optically coupled to the distributed Bragg reflection region. Each of the high refractive index portions includes a semiconductor wall including upper and lower portions that are arranged in a direction intersecting with the principal surface of the substrate. The principal surface is disposed between the upper and lower portions. The lower portion includes a part of the substrate.

Abstract: An LED module according to the present invention is an LED module including a plurality of light-emitting diodes, wherein the plural light-emitting diodes are disposed only on a lateral surface of a right cone, a right pyramid, a truncated right cone, or a truncated right pyramid; the lateral surface has an inclination angle of 55° or more and 82° or less with respect to a bottom surface; the plural light-emitting diodes have light-emitting surfaces substantially parallel to the lateral surface; and angles formed between projection lines of lines normal to light-emitting surfaces of adjacent light-emitting diodes or adjacent ones of grouped light-emitting diodes, the projection lines being drawn on the bottom surface, are all equal to each other and are 72° or less.

Abstract: A wavelength selective switch includes a dispersion optical system dispersing wavelength multiplexing light obtained by multiplexing the plurality of frequency components to the plurality of frequency components by giving a dispersion angle having nonlinear frequency dependency to each of a plurality of frequency components; a light deflection element deflecting the plurality of frequency components; a condensing element condensing the plurality of frequency components on the light deflection element; and a prism optical system optically coupled to the dispersion optical system and the condensing element, and adapting spatial positions of the frequency components incident on the light deflection element to change linearly for frequencies by linearizing the frequency dependency of the dispersion angles and making incident the plurality of frequency components on the condensing element.