Abstract: The present invention relates to a method for manufacturing vertical optical coupling structures (1) between first optical or optoelectronic components (2) and second optical or optoelectronic components (3). Said vertical optical coupling structures are made by: (1) depositing a main layer (A) onto a substrate (25) including second optical or optoelectronic components; and (ii) lithography and/or physico-chemical etching of the main layer. Each vertical optical coupling structure is made such as to be located facing and making contact with a second optical component located in the substrate. The unitary main layer comprises generally frusto-conical coupling portions (12) consisting of a material having a refractive index greater than the refractive index of air.

Abstract: An optical transmitter may generate a first optical signal having a first wavelength and a second optical signal having a second wavelength. The optical transmitter may output the first and second optical signals to a link without performing a multiplexing operation. The optical transmitter may output part of the first optical signal to the link while part of the second optical signal is being output to the link. An optical receiver may receive the first and second optical signals, via the link, as separate optical signals. The optical receiver may receive part of the first optical signal from the link while part of the second optical signal is being received from the link. The optical receiver may provide the first and second optical signals to a photodetector array that includes a first photodetector to detect the first optical signal and a second photodetector to detect the second optical signal.

Abstract: To improve light use efficiency and thereby achieve even higher sampling rates. An optical measurement device includes: a light source configured to emit illumination light including a plurality of wavelength components; an optical system configured to introduce an axial chromatic aberration into the illumination light from the light source and to receive reflection light reflecting from a measurement object where at least a portion of the measurement object lies along a line extending from the optical axis of the optical system; a spectrometer for separating the reflection light received at the optical system into wavelength components, and a detector including a plurality of light receiving elements arranged one-dimensionally to correspond to the dispersion direction of the spectrometer.

Abstract: Embodiments of the present invention are directed to fiber optic element devices, methods for aligning fiber optic elements, and batch formation methods for creating such fiber optic alignment devices.

Abstract: An optical end coupling type silicon optical integrated circuit is provided using an SOI substrate. This optical integrated circuit is constituted so as to connect with an external optical circuit at an end coupling part and have signal light incident to an optical circuit that includes a curved part. In the plane of the optical integrated circuit, the position of one end coupling part selected from among any thereof and the position of any multimode optical waveguide element to which a respective optical waveguide is connected via a respective curved part satisfy a positional relationship defined on the basis of a beam divergence angle [theta] of stray light.

Abstract: Waveguide connectors and methods of forming the same include heating a polymer waveguide having one or more waveguide cores and alignment features to a first temperature. A ferrule having alignment features is heated to the first temperature, the ferrule having a different coefficient of thermal expansion from the polymer waveguide. The alignment features of the polymer waveguide align with the alignment features of the ferrule when the polymer waveguide and the ferrule are heated to the first temperature. The polymer waveguide is positioned on the ferrule without a waveguide backfilm. The alignment features of the polymer waveguide are bonded to the corresponding alignment features of the ferrule.

Abstract: An optical device includes: an optical element with a surface including one of a light-receiving portion and a light-emitting portion; a resin layer provided over the one of light-receiving portion and the light-emitting portion; and a resin lens provided over the resin layer, wherein the resin layer includes a first shape larger than a second shape of the resin lens in a direction parallel to the surface.

Abstract: An optical system may include a substrate that includes an etched region and a laser-induced breakage region. The optical system may further include an optical waveguide disposed on the substrate. The optical system may further include an optical device coupled to the optical waveguide within the etched region. The laser-induced breakage region may produce a predetermined coupling gap between the optical waveguide and the optical device.

Abstract: This disclosure generally relates to high-speed fiber optic networks that use light signals to transmit data over a network. The disclosed subject matter includes devices and methods relating to multi-lens optical components and/or optoelectronic subassemblies. In some aspects, devices and methods relate to an optical component including a housing defining a cavity and a lens array having a plurality of lenses on an optically transmissive portion of the housing. In some aspects, devices and methods relate to an optical component including a substrate; and a lens array on the substrate, the lens array having a plurality of discrete lenses.

Abstract: Fiber optic connector assemblies and method for assembling the same are disclosed. In one embodiment, a fiber optic connector assembly includes an optical fiber having an inner glass region, a polymer layer surrounding the inner glass region, and a windowed portion, wherein the inner glass region is exposed at the windowed portion. The fiber optic connector assembly further includes a connector body having a demarcation region at a first end, wherein the optical fiber is disposed within the connector body such that at least a portion of the windowed portion is positioned in the demarcation region, and the optical fiber is adhered to the connector body at the windowed portion. In another embodiment, the demarcation region includes an opening in the outer jacket that exposes the at least a portion of the windowed portion of the plurality of optical fibers and the optical fibers are adhered to a portion of the cable.

Abstract: An optical subassembly (1) includes a photonic integrated circuit (2), an external optical system (4) and an optical interface (6) that is arranged between the PIC and the external optical system. The optical subassembly includes a third material (7) and a fourth material (8). The third material (7) at least partially fills the optical interface between the PIC and the external optical system in order to minimize contamination of any kind. The fourth material (8) being in contact at least with the third material for sealing at least the third material from ambient moisture. In this way a low-cost near-hermetic environmental protection barrier (7, 8) may be provided. An optical system (14) including the optical subassembly and a method of fabricating such an optical subassembly are also described.

Abstract: A multi-channel optical module includes a stem configured to allow an optical active element transmitting and receiving an optical signal to be installed thereon, an optical module frame connected to the stem and configured to have an optical element forming an optical path corresponding to the optical active element, and an external housing configured to house the optical module frame therein and coupled to the stem, wherein the optical element includes a lens and a filter unit disposed in the optical path and an optical waveguide element to which an optical fiber is connected.

Abstract: An inventive opto-electric hybrid board includes: opto-electric module portions respectively provided on opposite end portions of an elongated insulation layer and including a first electric wiring of a first electrically conductive pattern and an optical element provided on a front surface of the insulation layer; and an interconnection portion provided on a portion of the insulation layer extending from the opto-electric module portions, and including an elongated optical waveguide on a back surface of the insulation layer optically coupled with the optical elements, and having a light signal transmission core. Further, an electrically conductive dummy pattern is provided on the front surface of the insulation layer in the interconnection portion for reinforcing the interconnection portion. The electrically conductive dummy pattern reinforces the interconnection portion to protect the waveguide from bending and twisting, while ensuring the flexibility of the interconnection portion.

Abstract: A cable connector assembly comprises a cable, a connector connected with the cable. The connector comprises a plurality of contacts electrically connecting the cable, an insulative housing retaining the contacts, a metal shell having a top shell and a bottom shell assembled with each other around the insulative housing, and a fixing member fixing the cable. The bottom shell includes a rear wall having a opening for the cable to be inserted into. The top shell includes a top wall and a tongue piece extending from the top wall to the cable. The fixing member includes a main body fastening the cable and a soldering portion extending from the main body and soldering with the rear wall of the bottom shell.

Abstract: A multi-core optical fiber (100) comprises a plurality of optical cores (1, . . . , 8) to respectively transmit light and a plurality of cleaves (110a, 100b, 110c, 110d, 110e, 110f, 110g, 110h) extending from a surface (102) of the multi-core optical fiber (100) into the multi-core optical fiber. A first cleave (110a) comprises a surface (111a) to couple light out of the optical fiber, wherein a first optical core (1) ends at the surface (111a) of the first cleave (110a). An at least one second cleave (110b, . . . , 110h) comprises a surface (111b, . . . , 111h) to couple light out of the optical fiber, wherein at least one second optical core (2, . . . , 8) ends at the surface (111b, . . . , 111h) of the at least one second cleave (110b, . . . , 110h). The first and the at least one second cleave (110a, . . . , 110h) are staggered along the longitudinal axis (101) of the multi-core optical fiber (100).

Abstract: The present disclosure relates to a method for manufacturing one or more optical engine packages, each optical engine package comprising a silicon photonic die. The method includes receiving a substrate comprising a package portion and a cutting area adjacent to the package portion, assembling the optical engine package on the substrate such that an edge-coupled waveguide of the silicon photonic die overlaps a boundary between the cutting area and the package portion, and cutting the optical engine package and the substrate in the cutting area to expose the edge-coupled waveguide for optical coupling thereof to an optical fiber core.

Abstract: Exemplary embodiments of methods and apparatuses to provide an electro-optical alignment are described. An electrical connector is formed on a printed circuit board substrate that extends onto a side surface of the substrate to form an electrical turn. An optoelectronic die is placed onto the printed circuit board substrate. The optoelectronic die on the printed circuit board substrate is erected over a mounting board to provide optical coupling substantially parallel to the mounting board.

Abstract: Disclosed is an electronic apparatus including a circuit element including a first main surface, a first electrode provided in the first main surface, an optical element including a second main surface and being configured to either transmit or receive an optical signal, a second electrode provided in the second main surface, a window which is provided in the second main surface and through which the optical signal passes, a wiring layer provided on the first main surface and the second main surface, the wiring layer electrically connecting the first electrode and the second electrode, and an optical waveguide, which is provided on the second main surface and optically connected to the window, the optical signal passing through the optical waveguide.

Abstract: In an integrated optical receiver or transmitter, both the displacement of an optical axis caused by thermal changes and the property degradation of an optical functional circuit are inhibited. A planar lightwave circuit having a substrate and a waveguide-type optical functional circuit formed thereon composed of a material different from that of the substrate, and includes a waveguide region formed only of an optical wavelength that is in contact with a side forming an emission-end face of the optical waveguide for propagating the light emitted from the optical functional circuit or an incident-end face of an optical waveguide for propagating the light incident on the optical functional circuit. The planar lightwave circuit is fixed to a fixing mount only at the bottom of the substrate where the waveguide region is formed.

Abstract: Waveguide connectors and methods of forming the same include heating a polymer waveguide having one or more waveguide cores and alignment features to a first temperature. A ferrule having alignment features is heated to the first temperature, the ferrule having a different coefficient of thermal expansion from the polymer waveguide. The alignment features of the polymer waveguide align with the alignment features of the ferrule when the polymer waveguide and the ferrule are heated to the first temperature. The polymer waveguide is positioned on the ferrule without a waveguide backfilm. The alignment features of the polymer waveguide are bonded to the corresponding alignment features of the ferrule.

Abstract: A method for monolithically integrating semiconductor waveguides, photodetectors and logic devices, i.e., field effect transistors, on a same substrate is provided. The method includes the use of a double semiconductor-on-insulator substrate that includes from bottom to top, a handle substrate, a first insulator layer, a first semiconductor material layer, a second insulator layer, and a second semiconductor material layer. The waveguides, photodetectors and logic devices can be formed in different regions of the substrate and are present atop a first insulator layer of the double semiconductor-on-insulator substrate.

Abstract: A v-groove assembly is used to edge couple a lensed fiber (e.g., an optical fiber made of silica) with a waveguide in a photonic chip. The v-groove assembly is made from fused silica. Fused silica is used to so that an adhesive (e.g., epoxy resin) used in bonding the lensed fiber to the v-groove assembly and/or bonding the v-groove assembly to the photonic chip can be cured, at least partially, by light.

Abstract: A semiconductor device, a package structure, and methods of forming the same are disclosed. An embodiment is a semiconductor device comprising a first optical device over a first substrate, a vertical waveguide on a top surface of the first optical device, and a second substrate over the vertical waveguide. The semiconductor device further comprises a lens capping layer on a top surface of the second substrate, wherein the lens capping layer is aligned with the vertical waveguide, and a second optical device over the lens capping layer.

Abstract: An edge coupling method comprising positioning a first photonic device such that a first edge coupler of the first photonic device is at least partially aligned with a first alignment waveguide of a second photonic device and such that a second edge coupler of the first photonic device is at least partially aligned with a second alignment waveguide of the second photonic device, wherein the first edge coupler widens towards an edge of the first photonic device and the second edge coupler widens towards the edge, and wherein the first edge coupler and the second edge coupler are optically coupled to each other by an interconnect, transmitting a light through the first alignment waveguide, detecting the light at the second alignment waveguide, and aligning the first photonic device and the second photonic device based on the detecting.

Abstract: An optical communication device includes a printed circuit board (PCB), a light emitting element, a light receiving element, and a light waveguide. The PCB includes a substrate. The substrate includes a first end surface and a second end surface opposite to the first end surface. The light emitting element is electrically connected to the first end surface. The light receiving element is electrically connected to the second end surface. The light waveguide includes a light incident end and a light emergent end. The light waveguide is embedded in the substrate. The light incident end is exposed to the first end surface and optically aligned with the light emitting element along a transmitting direction of the light waveguide. The light emergent end is exposed to the second end surface and optically aligned with the light receiving element along the transmitting direction of the light waveguide.

Abstract: An apparatus includes a base substrate, a light rotation module and a flexible printed circuit board (PCB). The light rotation module has a bottom surface mounted on the base substrate and a top surface coupled to one or more optoelectronic transducers, and is configured to direct optical signals between the respective optoelectronic transducers and optical ports on a side perpendicular to the top surface. The flexible printed circuit board (PCB) includes a first end that is attached to the top surface of the light rotation module and has the optoelectronic transducers mounted thereon, a second end attached to the base substrate, and conductive traces disposed between the first and second ends to direct electrical signals between the optoelectronic transducers and the base substrate.

Abstract: To fabricate an interposer for interfacing waveguides (e.g. optical fiber cables) to transducers, a cavity (410) is formed in a top surface of a substrate. A first layer (520) is formed over the cavity's bottom surface, with one or more gaps in the first layer's top surface. A second layer (3410) is formed in the one or more gaps. The second layer overlaps the first layer. At least part of the first layer is removed to form channels separated from each other by portions of the second layer that are located in the one or more gaps; at least part of the first layer is removed from under the second layer. The second layer portions in the one or more gaps provide one or more spacers in the cavity; these one or more spacers at least partially cover the channels. Waveguides can be placed into the channels.

Abstract: An MF connector module is provided that positions the fiber end portions relative to respective V-grooves of the module in such a way that the fiber end portions can be bent, and thereby loaded, by a predetermined amount when the fiber end portions are being installed in the respective V-grooves. The bending of the fiber end portions ensures that the optical axes of at least the tips of the fiber end portions are parallel to the optical axes of the respective V-grooves. The loading of the fiber end portions caused by the bending ensures that significant lengths of the fiber end portions are tangent to and in contact with the inner walls of the respective V-grooves. This tangential contact between the fiber end portions and the inner walls of the V-grooves causes the fiber end faces to be precisely aligned with the respective optical axes of the MF connector module.

Abstract: A connector comprises a base insulator, a plurality of elongated plate shaped contacts arranged on the base insulator, and a cover insulator arranged to hold the contacts in cooperation with the base insulator and welded to the base insulator, the base insulator is provided with a pair of openings arranged to face each other across each of holders and to intersect with the direction in which the holders are arranged.

Abstract: An approach is provided for forming a light coupling in a waveguide layer. The approach involves forming a waveguide layer overlaying an upper surface of a substrate. The approach also involves placing a chip package portion within the waveguide layer in a selected position. The approach further involves forming a molding compound layer overlaying the waveguide layer and the chip package portion. The approach additionally involves curing the molding compound layer to form a cured package. The approach also involves releasing the cured package from the substrate and inverting the cured package. The approach further involves forming a ridge waveguide structure in the waveguide layer by removing a portion of the lower surface of the cured package.

Abstract: A structured substrate for optical fiber alignment is produced at least in part by forming a substrate with a plurality of buried conductive features and a plurality of top level conductive features. At least one of the plurality of top level conductive features defines a bond pad. A groove is then patterned in the substrate utilizing a portion of the plurality of top level conductive features as an etch mask and one of the plurality of buried conductive features as an etch stop. At least a portion of an optical fiber is placed into the groove.

Abstract: An apparatus is disclosed comprising a planar optical waveguide structure which includes a substrate and two planar optical waveguides thereon. The apparatus further comprises a solid structure having a body and two branches connected to the body. Each of the two branches has a reflective surface area thereon. Each of the two planar optical waveguides is configured to optically couple light from an end thereof to the reflective surface area of a corresponding one of the branches. The planar optical waveguide structure further includes a third planar optical waveguide on the substrate. The third planar optical waveguide has a segment located between the solid structure and the substrate.

Abstract: A LED light bar, a related planar light source and a method of manufacturing such light bar is provided. The light source includes a light guide plate having a first surface and a second surface; at least one light bar, on which a plurality of LEDs is disposed, wherein the light bar is disposed on a lateral side of the light guide plate, and the LEDs are disposed inside the light guide plate to output light; a reflector, which is disposed outside the second surface and reflects light; and a diffuser, which is disposed outside the first surface and scatters reflected light of the reflector. Because LEDs are pre-disposed in a mold when the light guide plate is manufactured, the LEDs and the light guide plate are integrally formed, the loss of light can be avoided, and the efficiency of the planar light source can be enhanced.

Abstract: An optical coupling system for coupling a first optical waveguide having a first core surrounded by a first sheath to a second optical waveguide having a second core surrounded by a second sheath. An end face of the first core of the first optical waveguide abuts an end face of the second core of the second optical waveguide at a coupling location and the second core is flush with the first core in the axial direction, wherein, in the region of the coupling location, over at least part of a predetermined axial portion, both the second sheath of the second optical waveguide and the first sheath of the first optical waveguide together form a cladding of the optical waveguide in the predetermined portion.

Abstract: A glass-silicon wafer stacked platform. The platform includes a plurality of silicon pillars defining a ferrule receptacle, a silicon spacer connected to bases of the pillars and enclosing an aperture, a glass wafer bonded to the spacer, a microlens array formed in a first surface of the glass wafer and located in the aperture, conductive material carried by a second surface of the glass wafer, and contacts in electrical communication with the conductive material.

Abstract: In order to provide a spot size converter and a method for making the same which enable the optical connection with low loss and are able to reduce the excess loss for the position misalignment in mounting, a spot size converter according to an exemplary aspect of the present invention includes: a substrate on which an optical waveguide including a first core is laminated and which includes a notch; a core reducing part which is formed so that a cross-section area of the first core may gradually decrease toward an end part of the first core in the direction of light propagation; a second core which surrounds the core reducing part and is made of a material whose refractive index is smaller than that of the first core; a peripheral clad which surrounds the second core and is made of a material whose refractive index is smaller than that of the second core; and a lower clad which is formed in a lower part of the second core and includes the peripheral clad; wherein the lower clad is formed in the notch.

Abstract: An object of the present invention is to provide a laser light source that includes a laser element and an optical element that are optically coupled efficiently and directly. A laser light source includes, a laser element which has a ridge part and emits laser light from a light emission part, an optical element which has a waveguide for guiding the laser light that is incident on an incidence part; and a substrate for joining the laser element and the optical element close so as to be optically coupled directly, and, in this laser light source, the laser element and the optical element are joined to the substrate in a state in which a position of the incidence part is shifted a predetermined distance upward or downward with respect to a position of the light emission part.

Abstract: An optical coupler may include a fiber optic structure that has a portion of an outer surface that is beveled at a predetermined angle relative to a longitudinal axis of the fiber optic structure. The beveled outer surface portion may be optically coupled with a waveguide core of an optical integrated circuit. The fiber optic structure may also include a second outer surface portion that is butt coupled to an end of an optical fiber to optically couple the second outer surface portion with the optical fiber.

Abstract: In an integrated optical receiver or transmitter, both the displacement of an optical axis caused by thermal changes and the property degradation of an optical functional circuit are inhibited. A planar lightwave circuit having a substrate and a waveguide-type optical functional circuit formed thereon composed of a material different from that of the substrate, and includes a waveguide region formed only of an optical wavelength that is in contact with a side forming an emission-end face of the optical waveguide for propagating the light emitted from the optical functional circuit or an incident-end face of an optical waveguide for propagating the light incident on the optical functional circuit. The planar lightwave circuit is fixed to a fixing mount only at the bottom of the substrate where the waveguide region is formed.

Abstract: An optical module includes a substrate, an optical device including a surface-emitting or -receiving element mounted on a surface of the substrate with a light-emitting or -receiving portion, an optical fiber disposed parallel to the surface of the substrate and in a longitudinal direction of the substrate, a damming member provided between the optical device and the substrate to extend in a width direction of the substrate and dividing a gap between the optical device and the substrate in the longitudinal direction of the substrate into a first portion and a second portion, and a mirror provided at one side surface of the damming member a tip of the optical fiber. The first portion provided on an opposite side to the optical fiber is filled with an underfill resin, and the second portion provided on a side close to the optical fiber is filled with an optical fiber fixing resin.

Abstract: The laser device includes an amplifier including a III-V heterostructure arranged to generate photons, and a waveguide which forms a loop and is optically coupled to the amplifier. The amplifier is arranged facing the waveguide only in the region of a first section of the waveguide.

Abstract: An optical module (30) includes an optical waveguide (31), a first ferrule and a second ferrule (32, 33) connected with the optical waveguide. The optical waveguide includes 2N optical channels (313). The first and the second ferrules includes N mirrors (34, 36) and N+1 lenses (35, 37). N of the 2N optical channels optically couple the N mirrors (34) of the first ferrule with N of the N+1 lenses (37) of the second ferrule, and the remaining N of the 2N optical channel couple N of the N+1 lenses (35) of the first ferrule with the N mirrors (36) of the second ferrule.

Abstract: An optical printed circuit board is provided. The optical printed circuit board includes an insulation member, an optical fiber disposed in the insulation member and having opposite end portions exposed to a side of the insulation member, and at least one supporting member provided with a guide portion coupled to the opposite end portions of the optical fiber and guiding bending of the optical fiber.

Abstract: An optical interposer comprising: (a) a substrate having a planar surface: (b) at least one groove defined in the planar surface and extending from an edge of the substrate to a terminal end, the groove having side walls and a first facet at the terminal end perpendicular to side walls, the facet having a first angle relative to the planar surface, the first angle being about 45 degrees; and (c) a reflective coating on the first facet.

Abstract: An optical element package includes an optical wave guide array, at least one optical assembly and at least one optical transmission member. The optical wave guide array has a reflection groove. The reflection groove includes a reflection surface. The at least one optical assembly is positioned on the optical wave guide array adjacent to the reflection surface. The at least one optical transmission member is positioned on the optical wave guide array, and is optically coupled with the reflection surface. The optical signals emitted by the at least one optical assembly are reflected by the reflection surface and then reaching the at least one optical transmission member for transmission.

Abstract: An optical module includes a photoelectric conversion element optically connected to an optical fiber, a plate-shaped substrate mounting the photoelectric conversion element, coupling members fixed to both end portions of the substrate so as to sandwich the photoelectric conversion element, and a cover member coupled to the substrate by the coupling members so as to cover at least a portion of the substrate.

Abstract: A polarization conversion device includes: a directional coupler that includes an input side optical waveguide and an output side optical waveguide which are disposed in parallel to each other and each of which has a core. Assuming that a direction in which the input side optical waveguide and the output side optical waveguide face each other is a width direction and a direction perpendicular to the width direction is a height direction in a cross section perpendicular to a longitudinal direction of each of the input side optical waveguide and the output side optical waveguide, and the directional coupler is configured to couple first light guided through the input side optical waveguide to second light guided through the output side optical waveguide, the polarization direction of the second light is perpendicular to that of the first light.

Abstract: Conventionally, there has been a problem that a structure in which optical signals outputting from a substrate facet in a PLC are optically coupled to a different bulk type optical device is so complicated that its assembly is laborious. There also has been a problem that a structure in which an output facet of a PLC is polished with an angle results in an increase in coupling loss in free space optics. With a lens bonded to an angled facet of a PLC, an optical circuit of the present invention achieves an optical coupling, with low loss, to a bulk-type optical device or another PLC with a simple structure. Moreover, a lens part and an optical fiber part are respectively bonded to different core apertures exposed on a single angled facet. Thereby, optical signals can be inputted to and outputted from the PLC through the single facet.

Abstract: An optical interposer for optically coupling light between an OED supported on a substrate and an optical fiber, the interposer comprising: (a) an interposer of an optically-clear moldable material comprising at least the following features: (b) a port for receiving a ferrule containing at least one optical fiber, the port comprising an interface surface positioned to optically couple with an end face of the optical fiber; (c) an active lens adapted to optically couple with an OED, the active lens and the interface surface optically coupled along an optical path in the interposer; (d) a protrusion extending backward from the port, the protrusion defining a first register surface, the first register surface being a certain distance from the optical path such that, when a second register surface of a ferrule containing the optical fiber contacts the first register surface, the ferrule is aligned with the port such that the port can receive a front portion of the ferrule if the ferrule is pushed forward.

Abstract: The photo module is provided with an incident light fiber guiding light, a gradient index lens having an optical axis different from the incident light fiber, having a period length larger than a ¼ period length and smaller than a ½ period length with respect to the wavelength of the incident light, joined to the incident light fiber on a surface forming a finite angle with a surface vertical to the optical axis, and having, as a light exit surface of emitting light, a surface substantially vertical to the optical axis, and a light receiving element disposed at a position where the emitting light is collected and measuring the strength of the emitting light.