Abstract: A method of manufacturing a polarizing glass sheet includes subjecting, while heating, a glass preform sheet containing metal halide particles to down-drawing, to thereby provide a glass member having stretched metal halide particles dispersed in an aligned manner in a glass matrix, and subjecting the glass member to reduction treatment to reduce the stretched metal halide particles, to thereby provide a polarizing glass sheet. A shape of the glass preform sheet during the down-drawing satisfies a relationship of the following expression: L1/W1?1.0 where L1 represents a length between a portion in which a width of the glass preform sheet has changed to 0.8 times an original width and a portion in which the width of the glass preform sheet has changed to 0.2 times the original width W0, and W1 represents a length equivalent to 0.5 times the original width W0 of the glass preform sheet.

Abstract: A transmitter optical subassembly is disclosed including a substrate and a direct modulated laser disposed on the substrate. A single-stage isolator, a polarization direction rotator, and an optical branching filter are disposed side by side on the substrate in a light propagation direction. The polarization direction rotator can adjust linearly polarized light to P-polarized light, the optical branching filter includes an optical splitter subassembly and a filter subassembly, and an optical splitter film in the optical splitter subassembly is an optical splitter film with P polarization. The polarization direction rotator adjusts the incident linearly polarized light to the P-polarized light, and the optical splitter film in the optical branching filter is the optical splitter film with P polarization; all P-polarized light with single polarization can pass through the optical branching filter, without causing any polarization loss or two peaks.

Abstract: The present disclosure provides a laser cutting method. The laser cutting method is applied to cut a polarizer. The method includes: providing a non-linearly polarized light; adjusting the non-linearly polarized light to a first linearly polarized light by a polarization adjusting device; and cutting the polarizer by the first linearly polarized light.

Abstract: An optical module includes a first semiconductor light-emitting element, a second semiconductor light-emitting element, a first lens, a second lens, a filter that multiplexes the first light and the second light, a base plate that has a first surface on which the first semiconductor light-emitting element, the second semiconductor light-emitting element, the first lens, the second lens, and the filter are mounted and a second surface opposite the first surface in a thickness direction, and a support base that is in contact with a part of the second surface and that supports the base plate. The base plate has a filter mounting region in which the filter is mounted. The optical module has a gap between a region of the second surface corresponding to the filter mounting region and the support base.

Abstract: An edge-emitting laser including a substrate, a lower power optical cavity located on the substrate and a higher power optical cavity located on the substrate adjacent the lower power optical cavity. The lower power optical cavity includes a first active gain section having a first length. The higher power optical cavity includes a second active gain section having a second length greater than the first length.

Abstract: Devices and methods are described herein to measure optical power in scanning laser projectors. In general, the devices and methods utilize a polarizing component and photodiode to measure optical power being generated by at least one laser light source. The polarizing component is configured to polarize at least a portion of the laser beam in a way that improves the accuracy and consistency of this optical power measurement. Specifically, the polarizing component filters at least a portion of the laser beam for one polarization state in a way that facilitates improved reliability in the amount of laser light directed into the photodiode.

Abstract: A collimation lens and an optical module of the collimation lens. The collimation lens includes a front convex aspheric lens, a first polarizing filter, a Faraday rotation (FR) crystal, a second polarizing filter, and a rear convex aspheric lens. The front convex aspheric lens is coupled to a first end face of the collimation lens, and the rear convex aspheric lens is coupled to a second end face of the collimation lens. The first polarizing filter is coupled between the front convex aspheric lens and the FR crystal, and the second polarizing filter is coupled between the FR crystal and the rear convex aspheric lens.

Abstract: A LIDAR system, optical coupler for a LIDAR system and method of optical communication. The LIDAR system includes an optical coupler having a chip-side face in optical communication with a photonic chip and a scanner-side face in optical communication with a scanner, the optical coupler comprising a polarization rotator and a birefringent wedge. A first beam of light is transmitted from the first location toward a chip-side face of an optical coupler to direct the first beam of light, via the optical coupler, along an optical path at a scanner-side face of the optical coupler. A second beam of light is received along the optical path at the scanner-side face and directed the second beam of light toward a second location.

Abstract: An embedded, inverse wire-grid polarizer (WGP) includes ribs 13 located over a surface of a transparent substrate 11, gaps 16 between the ribs 13, and a fill-layer 15 substantially filling the gaps 16. The fill-layer has a relatively high index of refraction, such as greater than 1.4. At a wavelength of light incident upon the WGP, E? transmission can be greater than E? transmission. E? is a polarization of light with an electric field oscillation parallel to a length L of the ribs, and E? is a polarization of light with an electric field oscillation perpendicular to a length L of the ribs. This embedded, inverse WGP is especially useful for polarizing, with high WGP performance, small wavelength (high-energy) regions of the electromagnetic spectrum (e.g. UV) which are difficult to polarize with conventional WGPs (E? transmission>E? transmission).

Abstract: The disclosure is directed to an element that is capable of acting as both an optical polarizer and an optical attenuator, thus integrating both functions into a single element. The element comprises a monolithic or one piece glass polarizer (herein also call the “substrate”), a multilayer “light attenuation or light attenuating” (“LA”) coating that has been optimized for use at selected wavelengths and attenuations deposited on at least one polarizer facial surface, and a multilayer anti-reflective (AR) coating on top of the LA coating. The disclosure is further directed to an integrated optical isolator/attenuator comprising a first and a second polarizing elements and a Faraday rotator for rotating light positioned after the first polarizing element and before the second polarizing element, the integrated optical isolator/attenuator both polarizing and attenuation a light beam from a light source.

Abstract: A wire grid polarizer (WGP) 10 can include wires 15 sandwiched between a first pair of thin-film layers 21 (with a first transparent layer 11 and a second transparent layer 12) and a second pair of thin-film layers 22 (with a third transparent layer 13 and a fourth transparent layer 14). An index of refraction of each outer transparent layer 11 and 14 can be greater than an index of refraction of the adjacent inner transparent layer 12 and 13, respectively. Material composition of the outer transparent layers 11 and 14 can be the same and material composition of the adjacent inner transparent layers 12 and 13 can be the same. There can be high reflection of one polarization (e.g. Rs1>93% and Rs2>93%) for light incident on either side of the WGP. The wires 15 can be embedded for protection.

Abstract: The invention relates to an optical isolator comprising a polarizer adapted to polarize a beam of incident light to form a beam of polarized light, an analyzer adapted to transmit said beam of polarized light and to polarize back-reflected light, a magneto-optical element disposed between the polarizer and the analyzer, which magneto-optical element rotates the polarization direction of said beam of polarized light, and a magnet generating a magnetic field penetrating said magneto-optical element. It is an object of the invention to provide a temperature-compensated optical isolator that achieves a high degree of isolation at a minimum insertion loss over a given temperature range, without any need of manual tuning. The invention proposes to make provision for an automatic actuator mechanically connected to said magneto-optical element to move said magneto-optical element relative to said magnet in response to a temperature variation or in response to a variation of the wavelength of the incident light.

Abstract: A polarizer according to the present invention includes a thin film with a constant thickness composed of a dielectric, and a plurality of slit-shaped through-holes each having the same width formed in the thin film and extending in a first direction. The plurality of through-holes are arranged on a surface of the thin film at a constant interval in a second direction perpendicular to the first direction.

Abstract: A translucent sintered body having the following basic composition: Ca(1?x)YbxF(2+x), where 0.4?x?1.0, or preferably Ca(1?x?y)YbxRyF(2+x+y), 0.4?x?1.0, 0?y?0.5 wherein R is at least one element selected from Ce, Pr, Sm, Eu and Y.

Abstract: A communication network element (10) comprising: an optical path (12) for an optical communication signal (14); a monitoring port (16) arranged to output an optical monitoring signal; an optical splitter (20) provided in the optical path, the optical splitter arranged to receive the optical communication signal and to split off a part of the optical communication signal to form the optical monitoring signal; and optical isolation apparatus (22) connected between the optical splitter and the monitoring port, the optical isolation apparatus arranged to transmit the optical monitoring signal propagating towards the monitoring port and arranged to apply an attenuation, IA, to an attacking optical signal (24) propagating from the monitoring port towards the optical splitter to thereby prevent a substantial part of the attacking optical signal being transmitted to the optical path.

Abstract: A light source module includes a single light source with two opposite light outputting faces, a first optical amplifier and a second optical amplifier provided on opposite sides of the light source adjacent to the corresponding light outputting faces, and a first monitor configured to monitor an output of the first optical amplifier, wherein a power output level of the first optical amplifier is controlled independently from the second optical amplifier based upon a monitoring result of the first monitor.

Abstract: The present invention provides a polarization beam combiner/splitter, a polarization beam combining/splitting structure, a light mixer, an optical modulator module, and a method for manufacturing a polarization beam combiner/splitter with suitable polarization beam combining/splitting characteristics. In the polarization beam combiner/splitter, a polarization beam combining/splitting film is placed on a substrate and allows TE light to pass through and causes TM light to branch off. A first optical waveguide is formed on the substrate with an end surface facing a first surface of the polarization beam combining/splitting film and with a waveguide direction coinciding with a propagation direction of the TE light. A second optical waveguide is formed on the substrate with an end surface facing a second surface of the polarization beam combining/splitting film and with a waveguide direction coinciding with a propagation direction of the TM light.

Abstract: The present application discloses various implementations of a laser scanning module. In one implementation, such a laser scanning module comprising an optical isolator including first and second linear polarizers, a collimating optics configured to receive light produced by a laser light source and to pass a substantially collimated light beam to the first linear polarizer, and a scanning unit situated to receive light passed by the second linear polarizer. The first linear polarizer is separated from the collimating optics by a first distance less than a second distance separating the second linear polarizer from the scanning unit.

Abstract: A ceiling mounted air conditioner is provided. The ceiling mounted air conditioner includes a main body configured to be fixed onto a ceiling and have an open bottom; an outlet panel configured to be coupled to a lower part of the main body and have a plurality of air outlets; an intake panel configured to be coupled to the outlet panel and have an air intake; a door panel configured to be lifted up or down from the bottom of the intake panel and thus to open or shut the air intake; and a human body sensor module configured to be installed in the door panel, to begin to operate when the door panel is lifted down and to sense a movement of a user. Since the ceiling mounted air conditioner can blow air-conditioned air toward the user in a localized manner, it is possible to improve the performance of the ceiling mounted air conditioner.

Abstract: A translucent sintered body having the following basic composition: Ca(1?x)YbxF(2+x), where 0.4?x?1.0, or preferably Ca(1?x?y)YbxRyF(2+x+y), 0.4?x?1.0, 0?y?0.5 wherein R is at least one element selected from Ce, Pr, Sm, Eu and Y.

Abstract: The present invention provides a garnet single crystal comprising a terbium aluminum garnet single crystal, wherein a portion of the aluminum is substituted with scandium, and a portion of at least one of the aluminum and terbium is substituted with at least one type selected from the group consisting of thulium, ytterbium and yttrium.

Abstract: A multi-pass-type Faraday rotator useful in an optical isolator is provisioned with high-efficiency, high-field permanent magnets formed with minimal magnetic material. A high magnetic field is generated by two sets of magnets attached to outer pole plates that are mirror images of each other. Like-type poles of the magnets in each set are disposed against each other above and below the beam path plane of a multi-pass Faraday optic. Each set of magnets is formed of a central block of magnetic material with magnetization oriented substantially parallel to the multi-pass beam path on the Faraday optic, adjoined by adjacent blocks of magnetic material with magnetization oriented substantially perpendicular to the central magnet block and with like poles to the central magnet block where the magnets border the multi-pass Faraday optic.

Abstract: An optical isolator capable of creating a larger safe buffer area for optical beam(s) and a manufacturing method thereof are disclosed. The optical isolator includes a sandwich type wafer, a first polarizer, a Faraday rotator and a second polarizer. The first polarizer works as the incident plane of the FSI (free space isolator), while the second polarizer works as the outgoing plane of the FSI. The direction in which the second polarizer passes the polarized beam is at a 45° angle with respect to the first polarizer. The manufacturing method includes marking the edge of the second polarizer. FSIs processed by this method provide a larger buffer area for the optical beam(s) and/or a lower manufacturing cost, even though the size of the FSI is unchanged.

Abstract: An optical module is provided that includes a Faraday rotator having a Verdet constant at a wavelength of 1.06 ?m of at least 0.27 min/(Oe·cm), a first hollow magnet disposed on the outer periphery of the Faraday rotator, and second and third hollow magnet units disposed so as to sandwich the first hollow magnet on the optical axis. The second and third hollow magnet units include 2 or more magnets equally divided in a direction of 90 degrees relative to the optical axis. A magnetic flux density B (Oe) applied to the Faraday rotator is in the range of 0.5×104?B?1.5×104. The Faraday rotator is disposed on a sample length L (cm) in the range of 0.70?L?1.10, and has an external diameter D (cm) in the range of 0.20?D?0.60.

Abstract: A transmitter optical module for emitting a polarization combined beam is disclosed. The transmitter optical module includes optical sources each emitting optical beams with polarizations substantially same with others, an optical isolator, and a polarization beam combiner (PBC). The optical isolator, by receiving the optical beams, outputs the optical beams with polarizations perpendicular to the other to the PBC.

Abstract: An optical isolator for use with a wavelength band of 600-800 nm is improved in that it has a Faraday rotator made of an oxide material in which said oxide material contains (TbxR1-x)2O3 such that 0.5?x?1.0, and R is scandium, yttrium or any lanthanoid but Tb.

Abstract: An optical material used in a UV-excited yellow light-emitting material and an optical isolator, capable of emitting yellow light stably and highly efficiently even if a large current is fed to obtain the high luminance emission. The optical material used for the UV-excited yellow light-emitting material (2) and the optical isolator (210) is an oxide containing Ce, which is a terbium cerium aluminum garnet type single crystal wherein a part of terbium of a terbium aluminum garnet type single crystal is substituted by cerium. The ratio of number of moles of cerium to the total number of moles of terbium and cerium, namely the composition ratio of cerium, preferably falls within the range from 0.01 mol % to 50 mol %. A part of aluminum may be substituted by scandium or further by any one of terbium, cerium, yttrium, lutetium, ytterbium, and thulium.

Abstract: A Faraday rotator may include a magnetic field forming section configured to form a magnetic field at a predetermined magnetic flux density in a predetermined region, a Faraday element disposed in the predetermined region, and a first heat exhaust member, disposed on the side of one primary plane of the Faraday element, configured to form an optical contact surface with the Faraday element and configured to allow light at a predetermined wavelength to pass.

Abstract: Provided is a polarization independent optical isolator including: wedge-shaped birefringent crystal plates each made of a LiNbO3 single crystal; a Faraday rotator 3 made of a magnetic garnet single crystal; and sapphire single crystal plates 2 and 4 bonded to light transmitting surfaces of the Faraday rotator, respectively. A light transmitting surface of each of the sapphire single crystal plates is formed in such a manner as to be offset from the c-plane of the sapphire single crystal plate. An incident angle ?a of imaginary light 300 on each of the sapphire single crystal plates, and an offset angles ?off of the light transmitting surface from the c-plane of each sapphire single crystal plates are set within predetermined ranges, the imaginary light 300 being represented by a bisector of an angle formed by optical axes of the ordinary ray and the extraordinary ray.

Abstract: Provided are a non-reciprocal unit used for a polarization dependent type optical isolator and a polarization dependent type optical isolator that are simple in structure, can prevent damages due to light and heat and can obtain a high extinction ratio. In a polarization dependent type optical isolator, an input side lens (first lens) (5), a first birefringence unit (7), a Faraday rotator (9), a second birefringence unit (11) and an output side lens (second lens) (15) are arranged from the input side to the output side. The polarization dependent type optical isolator (1) is connected with optical fibers (3, 17) on the input and output sides, respectively, wherein a wedge angle (?1) of the first birefringence unit (7) is different from a wedge angle (?2) of the second birefringence unit (11).

Abstract: An optical isolator with a collimator which is used at the tip end of a laser beam transmitting fiber utilized in a laser processing. The optical isolator can provide solutions to the problems how to make return lights to be isolated from an incident light path and how to prevent the light energy from being conducted to an incident fiber, a laser oscillator, the collimator, and the optical isolator. The solutions comprise light-receiving fibers (22 and 23) disposed at focal points of a collimator lens (5) to which reflected lights from a workpiece return through the optical isolator. The return lights are then led to a ceramic tube (24) where the return light energy is converted to thermal energy and dissipated.

Abstract: It is an object to provide a small-sized optical isolator that is suitable as an optical isolator used in a semiconductor laser used in applications such as medical treatment or optical measurement The optical isolator for a wavelength band of 320 to 633 nm of the present invention comprises a Faraday device having a Verdet constant at a wavelength of 405 nm of at least 0.70 min/(Oe·cm), and a first hollow magnet disposed on the outer periphery of the Faraday device and second and third hollow magnet units disposed so as to sandwich the first hollow magnet on the optical axis, the second and third hollow magnet units comprising 2 or more magnets equally divided in a direction of 90 degrees relative to the optical axis, the Faraday device having applied thereto a magnetic flux density B (Oe) within the range of Expression (1) below, and a sample length L (cm) on which the Faraday device is disposed being within the range of Expression (2) below. 0.8×104?B?1.5×104??(1) 0.25?L?0.

Abstract: An optical element transmits incident light having a particular polarization direction mainly by 0-order transmission and diffracts incident light having a perpendicular polarization direction. The optical element includes a periodic structure having a period equal to or greater than the wavelength of the incident light. The periodic structure includes first and second subwavelength concave-convex structures formed perpendicularly adjacent to each other in each period of the periodic structure. The first and the second subwavelength concave-convex structures have a period less than the wavelength of the incident light. A filling factor and a groove depth of the first and the second subwavelength concave-convex structures are determined such that they have the same effective refraction index with respect to the incident light having the particular polarization direction and a phase difference ? with respect to the incident light having the particular polarization direction.

Abstract: An optical isolator 1 element comprises a Faraday rotator 11 that rotates a polarization plane of light; a first polarizer of optical absorption type 12 arranged on one surface side of the Faraday rotator 11, the first polarizer 12 having a layer in which metal particles are distributed; and a second polarizer of optical absorption type 13 arranged on another surface side of the Faraday rotator 11, the second polarizer 13 having a metal particle layer in which metal particles are distributed in a density higher than the density of metal particles distributed in the metal particle layer of the first polarizer 12. The optical isolator 1 makes it possible to reduce a deterioration of isolation caused by occurring a reflected light reflected between the second polarizer 13 and the first polarizer 12.

Abstract: The present invention is a garnet-type single crystal represented by the following general formula: (Tb3-xScx)(Sc2-yAly)Al3O12-z??(1) (wherein, x satisfies 0<x<0.1).

Abstract: A kW Class optical isolator employs negative feedback to yield low focal shift over dynamically changing power levels. The isolator is useful as a kW fiber laser output isolator.

Abstract: The present invention relates to an optical insulator for high power optical radiation. The arrangement of the optical insulator comprises a Faraday rotator, comprising one or more Faraday media (4) and a magnet assembly (1) that allows for the receiving of multiple Faraday media (4). A polarizer assembly is arranged both in front of and behind the Faraday media (4). The magnet assembly (1) is formed by magnets (2) shaped in such a way that at least the outer-lying magnets are parallelepiped. The free aperture (3) is surrounded by three magnetic levels (12, 12?, 12?).

Abstract: An optical isolator capable of creating a larger safe buffer area for optical beam(s) and a manufacturing method thereof are disclosed. The optical isolator includes a sandwich type wafer, a first polarizer, a Faraday rotator and a second polarizer. The first polarizer works as the incident plane of the FSI (free space isolator), while the second polarizer works as the outgoing plane of the FSI. The direction in which the second polarizer passes the polarized beam is at a 45° angle with respect to the first polarizer. The manufacturing method includes marking the edge of the second polarizer. FSIs processed by this method provide a larger buffer area for the optical beam(s) and/or a lower manufacturing cost, even though the size of the FSI is unchanged.

Abstract: The disclosure is directed to an element that is capable of acting as both an optical polarizer and an optical attenuator, thus integrating both functions into a single element. The element comprises a monolithic or one piece glass polarizer (herein also call the “substrate”), a multilayer “light attenuation or light attenuating” (“LA”) coating that has been optimized for use at selected wavelengths and attenuations deposited on at least one polarizer facial surface, and a multilayer anti-reflective (AR) coating on top of the LA coating. The disclosure is further directed to an integrated optical isolator/attenuator comprising a first and a second polarizing elements and a Faraday rotator for rotating light positioned after the first polarizing element and before the second polarizing element, the integrated optical isolator/attenuator both polarizing and attenuation a light beam from a light source.

Abstract: The present invention relates to Eu (II) compound nanocrystals doped with transition metal ions. Such a constitution generates quantum size effects of an Eu (II) compound nanoparticle, while the transition metal ions can affect a magnetooptical property of the Eu (II) compound nanoparticle. Thus, the magnetooptical property can be improved.

Abstract: The present invention is produced by a composite with an Eu (II) compound nanoparticle and a metal nanoparticle. Such production generates quantum size effects of the Eu (II) compound nanoparticle, while the surface plasmon of the metal nanoparticle can be used. Thus, the magnetooptical property can be improved. In addition, a thin film may be produced by a composite with an Eu (II) compound nanoparticle and a metal nanoparticle.

Abstract: Embodiments of the invention utilize optical structures created by processes in the wafer fabrication foundry to form optical isolators and circulators. Grating coupling structures are utilized to couple light having a chosen polarization component into free space through non-reciprocal rotation material; said light is captured by another set of grating coupling structures after experiencing a 45 degree rotation of the polarization. By non-reciprocally rotating the polarization, the input and output ports of the optical isolator will be different depending on the direction of the light propagation. The amount of non-reciprocal rotation material utilized by embodiments of the invention may be small, and the grating coupling structures may be efficiently made to couple to each other as their field profiles may be matched and their position may be precisely defined by lithographic means.

Abstract: An optical isolator including a Faraday rotator that has a high Faraday effect and a high transmission factor in a wavelength used is provided. An optical isolator comprises at least: a Faraday rotator; a polarizer arranged on a light incidence side of the Faraday rotator; and an analyzer arranged on a light exit side of the Faraday rotator, wherein the Faraday rotator consists of an oxide that contains an ytterbium oxide (Yb2O3) with a mass ratio of 30% or more.

Abstract: A transparent ceramic having terbium oxide (Tb2O3) in a molar ratio of at least 40%; and at least one oxide selected among an yttrium oxide, a scandium oxide, and a lanthanide rare earth oxide, wherein (1) the crystal structure of the terbium-oxide-based ceramic does not contain a non-cubic-crystal phase, (2) the mean crystal particle diameter is in a range of 0.5 to 100 ?m, and (3) the ceramic comprises a sintering auxiliary having no incidence of deposition of a non-cubic-crystal phase in the crystal structure of the terbium-oxide-based ceramic. This transparent ceramic makes a magneto-optical element that performs at least as well as terbium gallium garnet or other existing monocrystal materials. It also makes a functional element for an optical isolator in the infrared region between 500 nm and 1.5 ?m having very little scattering and very few birefringence components.

Abstract: The object(s) of the invention is to provide a Faraday rotator, an optical isolator, and optical processing equipment, which has a transmittance higher than that of TGG, is capable of upsizing, and has a higher performance index in the visible wavelength region in general, and on wavelengths of up to 400 nm in particular. The Faraday rotator is characterized by containing as a main component a fluoride represented by the following general formula (1) or (2): RE1F3-x??(1) LiRE2F4-x??(2) where 0?x<0.1, and RE1 or RE2 is at least one element selected from the group of rare earth elements.

Abstract: The near-field extinction ratio of a polarizing glass is increased. A polarizing glass contains anisotropically shaped metal particles oriented and dispersed in a glass substrate, which contains 0.40-0.85 wt % Cl relative to the entire glass substrate. The Vickers hardness ranges from 360 to 420, the Knoop hardness number ranges from 400 to 495, or the glass substrate contains at least one component selected from the group consisting of Y2O3, La2O3, V2O3, Ta2O3, WO3, and Nb2O5. The content of each of the selected components ranges from 0.05-4 mole percent, and if a plurality of the components are selected, the total content of the components is 6 mole percent or less.

Abstract: Provided is a polarization independent optical isolator including: wedge-shaped birefringent crystal plates each being made of a YVO4 single crystal; a Faraday rotator 3 made of a magnetic garnet single crystal; and sapphire single crystal plates 2 and 4 bonded to light transmitting surfaces of the Faraday rotator, respectively. A light transmitting surface of each of the sapphire single crystal plates is formed in such a manner as to be offset from the c-plane of the sapphire single crystal plate. An incident angle ?a of imaginary light on each of the sapphire single crystal plates, and an offset angles ?off of the light transmitting surface from the c-plane of each sapphire single crystal plates are set within predetermined ranges, the imaginary light being represented by a bisector of an angle formed by optical axes of the ordinary ray and the extraordinary ray.

Abstract: An optical transmitter includes an optical isolator that includes a Faraday rotator transmitting light output from a light source, and has a first state in which the light is transmitted through the optical isolator when a first magnetic field is applied to the Faraday rotator, and a second state in which the amount of the light transmitted through the optical isolator is less than that in the first state when a second magnetic field different from the first magnetic field is applied to the Faraday rotator; a junction to which an optical transmission medium into which the light output from the optical isolator is input is connected; a magnetic-field generator that selectively applies the first magnetic field or the second magnetic field to the Faraday rotator; and a switching unit that switches the magnetic-field generator to the second state when the optical transmission medium is not connected to the junction.

Abstract: According to one embodiment, an optical isolation module includes first and second linear polarizers, a Faraday rotator situated between the first and second linear polarizers and a transmissive element including a half-wave plate also situated between the first and second linear polarizers. In one embodiment, a method for performing optical isolation includes rotating an axis of polarization of a linearly polarized light beam by a first rotation in a first direction, and selectively rotating a portion of the linearly polarized light beam by a second rotation in the first direction to produce first and second linearly polarized light beam portions. As a result, the first linearly polarized light beam portion undergoes the first rotation, and the second linearly polarized light beam portion undergoes the first and second rotations. The method further includes filtering one of the first and second linearly polarized light beam portions to produce a light annulus.

Abstract: It is an object of the present invention to provide a magneto-optical material containing as a main component an oxide that includes a terbium oxide and having a large Verdet constant at a wavelength in the 1.06 ?m region (0.9 to 1.1 ?m) and high transparency, and to provide a small-sized optical isolator suitably used in a fiber laser for a processing machine. The magneto-optical material of the present invention contains an oxide represented by Formula (I) below at a content of at least 99 wt %. (TbxR1-x)2O3??(I) (In Formula (I), x satisfies 0.4?x?1.0 and R includes at least one element selected from the group consisting of scandium, yttrium, and lanthanoid elements other than terbium.