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.

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 apparatus includes a susceptor and a protective pipe. A gas containing 50% or more of argon or nitrogen is used as a gas to be supplied into the susceptor. The protective pipe has a heat insulating region (17a) enclosed with a heat insulator (18) with a length of Db (mm) at the upper section thereof and a non-heat insulating region (17b) not enclosed with any heat insulators at the lower section thereof. The temperature of the glass fiber at the outlet of the protective pipe becomes 1700° C. or less. The outer diameter of the glass fiber at the outlet of the protective pipe is within a range of the target outer diameter of the glass fiber+6 ?m or less.

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: 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 wavelength dispersive element that divides a beam input from an input port, a beam director that deflects a wavelength component, and a free space optical system that optically couple a input/output unit, the wavelength dispersive element, and the beam director. The free space optical system converts a shape of the beam such that a size extending in a second plane is relatively smaller than a size extending in a first plane, and to have a long axis and a short axis in a third plane. The long axis is inclined with respect to the first direction. The beam director includes a beam directing region in which a plurality of beam directing elements are arranged. The beam directing region deflects the respective wavelength components toward the predetermined output port. The beam directing region is provided to correspond to the shape of the beam.

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: A dispersive device has a beam expanding optical system which includes first and second prisms each having a pair of faces inclined relative to each other, and expands light containing a plurality of wavelength components by passing the light through each of the faces of the first and second prisms; and a dispersive element which emits the light expanded by the beam expanding optical system, at different diffraction angles by the respective wavelength components. A direction of variation of an output angle of the light emitted from the beam expanding optical system due to temperature change is configured to be a direction to suppress variation of the diffraction angles of the respective wavelength components emitted from the dispersive element due to the temperature change.

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.

Abstract: A wavelength selective switch includes: a port array that includes an input port for inputting a signal light and an output port for outputting the signal light which are arranged in a first direction; a dispersive element that disperses the signal light in a second direction; a condensing element that condenses signal lights; a light deflection element that deflects the signal lights toward the output port; a first optical system that matches a beam waist position of the signal light incident onto the condensing element with a front focus of the condensing element in the optical axis direction, in a first plane that extends in the first direction; and a second optical system that shifts the beam waist position of the signal light incident onto the condensing element from the front focus in the optical axis direction, in a second plane that extends in the second direction.

Abstract: In a wavelength selective switch, a holding member is used to rotate one end of optical fibers and a collimator array around a rotation axis to thereby change an incident angle of collimated light with respect to incident surfaces of a beam expander optical system. When the incident angle of the collimated light on the beam expander optical system is changed, an amount of variation in an emission angle of light from the beam expander optical system is not proportional (inversely proportional) to the magnification of the beam expander optical system. Thus, this wavelength selective switch can easily fine-tune the incident position (beam position) of light with respect to each reflecting surface of a MEMS mirror by rotating the holding member.

Abstract: In a wavelength selective switch, a holding member is used to rotate one end of optical fibers and a collimator array around a rotation axis to thereby change an incident angle of collimated light with respect to incident surfaces of a beam expander optical system. When the incident angle of the collimated light on the beam expander optical system is changed, an amount of variation in an emission angle of light from the beam expander optical system is not proportional (inversely proportional) to the magnification of the beam expander optical system. Thus, this wavelength selective switch can easily fine-tune the incident position (beam position) of light with respect to each reflecting surface of a MEMS mirror by rotating the holding member.

Abstract: When a lower gauge pressure of a cooling tube part is set at A, and the number of divided units of the cooling tube part is set at N, and a length of each of the divided units of the cooling tube part is set at Li (i=1 to N), and a radius of each of the divided units of the cooling tube part is set at Ri (i=1 to N), and a gas flow rate of a coolant gas passed through each of the divided units of the cooling tube part is set at Qi (i=1 to N), and a viscosity coefficient of a coolant gas is set at ?1, and a radius of an optical fiber is set at r1, and a drawing speed of the optical fiber is set at V1, and a pressure loss of a straight tube part is set at B, and the number of divided units of the straight tube part is set at n, and a length of each of the divided units of the straight tube part is set at LLj (j=1 to n), and a radius of each of the divided units of the straight tube part is set at RRj (j=1 to n), and a gas flow rate of a pressurized gas passed through the straight tube part is set at Qgas, and a

Abstract: A wavelength selective switch includes a wavelength dispersive element that divides a beam input from an input port, a beam director that deflects a wavelength component, and a free space optical system that optically couple a input/output unit, the wavelength dispersive element, and the beam director. The free space optical system converts a shape of the beam such that a size extending in a second plane is relatively smaller than a size extending in a first plane, and to have a long axis and a short axis in a third plane. The long axis is inclined with respect to the first direction. The beam director includes a beam directing region in which a plurality of beam directing elements are arranged. The beam directing region deflects the respective wavelength components toward the predetermined output port. The beam directing region is provided to correspond to the shape of the beam.

Abstract: A dispersive device has a beam expanding optical system which includes first and second prisms each having a pair of faces inclined relative to each other, and expands light containing a plurality of wavelength components by passing the light through each of the faces of the first and second prisms; and a dispersive element which emits the light expanded by the beam expanding optical system, at different diffraction angles by the respective wavelength components. A direction of variation of an output angle of the light emitted from the beam expanding optical system due to temperature change is configured to be a direction to suppress variation of the diffraction angles of the respective wavelength components emitted from the dispersive element due to the temperature change.

Abstract: A wavelength selective switch includes: a port array that includes an input port for inputting a signal light and an output port for outputting the signal light which are arranged in a first direction; a dispersive element that disperses the signal light in a second direction; a condensing element that condenses signal lights; a light deflection element that deflects the signal lights toward the output port; a first optical system that matches a beam waist position of the signal light incident onto the condensing element with a front focus of the condensing element in the optical axis direction, in a first plane that extends in the first direction; and a second optical system that shifts the beam waist position of the signal light incident onto the condensing element from the front focus in the optical axis direction, in a second plane that extends in the second direction.

Abstract: An apparatus includes a susceptor and a protective pipe. A gas containing 50% or more of argon or nitrogen is used as a gas to be supplied into the susceptor. The protective pipe has a heat insulating region (17a) enclosed with a heat insulator (18) with a length of Db (mm) at the upper section thereof and a non-heat insulating region (17b) not enclosed with any heat insulators at the lower section thereof. The temperature of the glass fiber at the outlet of the protective pipe becomes 1700° C. or less. The outer diameter of the glass fiber at the outlet of the protective pipe is within a range of the target outer diameter of the glass fiber+6 ?m or less.

Abstract: In a wavelength selective switch, a holding member is used to rotate one end of optical fibers and a collimator array around a rotation axis to thereby change an incident angle of collimated light with respect to incident surfaces of a beam expander optical system. When the incident angle of the collimated light on the beam expander optical system is changed, an amount of variation in an emission angle of light from the beam expander optical system is not proportional (inversely proportional) to the magnification of the beam expander optical system. Thus, this wavelength selective switch can easily fine-tune the incident position (beam position) of light with respect to each reflecting surface of a MEMS mirror by rotating the holding member.

Abstract: An optical device 1 comprises an optical I/O unit 10, a transmissive diffraction grating 21, a lens 30, and a mirror array 40. The transmissive diffraction grating 21 has gratings, each extending along an x axis, formed at a fixed period, wavelength-splits the light received from the input port, and outputs wavelength-split light components. The transmissive diffraction grating 21 is rotatable about a predetermined axis. The transmissive diffraction grating 21 outputs the wavelength light components into directions which correspond to the respective wavelengths and are perpendicular to the rotary axis. The lens 30 focuses the wavelength light components wavelength-split and output by the transmissive diffraction grating 21 at respective positions different from each other.

Abstract: A bi-direction optical module with an arrangement to reduce the crosstalk noise is disclosed. The optical module comprises a laser diode (LD) driven by a differential signal and a photodiode (PD) on a single package. The PD is mounted on a position where the electrical potential measured from respective interconnections connected to the anode and to the cathode of the LD becomes the midpoint of the interconnections. The capacitances with respect the stem, where the LD and the PD are mounted thereon, viewed from the anode and the cathode of the LD becomes substantially equal to each other, or distances from the PD to respective interconnections are adjusted depending on the length of the interconnection facing the PD. Twisting the interconnections to the LD may be effective to reduce the crosstalk.