Abstract: A fiber coupler is provided, which includes a tubular enveloping structure and several optical fibers arranged in the enveloping structure, each of which has a fiber core and a fiber cladding surrounding same, in order to conduct laser radiation, and each of which extends from the first as far as the second end of the enveloping structure. The enveloping structure includes a tapering section which is tapered in a first direction from the first as far as the second end. In the tapering section, both a first ratio of the diameter of the fiber core to the diameter of the fiber cladding and also a second ratio of the diameter of the mode field of the laser radiation conducted in the optical fiber to the diameter of the fiber core, increases in the first direction for each optical fiber.

Abstract: The invention relates to a microstructured optical fiber for generating incoherent supercontinuum light upon feeding of pump light. The microstructured optical fiber has a first section and a second section. A cross-section through the second section perpendicularly to a longitudinal axis of the fiber has a second relative size of microstructure elements and preferably a second pitch that is smaller than a blue edge pitch for the second relative size of microstructure elements. The invention also relates to an incoherent supercontinuum source comprising a microstructured optical fiber according to the invention.

Abstract: Photonic integrated circuits required connection to germanium doped silica cored optical fibers or silica cored and fluorine doped silica cladding optical fibers which have low index contrast and large mode field diameters. However, the optical waveguide within a photonic integrated circuit such as formed using silicon-on-insulator or compound semiconductors tends to be high index contrast and small mode field diameter. Accordingly, it is necessary to implement adiabatic waveguide tapers with a high coupling efficiency and small footprint in order to couple into the photonic integrated circuits to/from the optical fiber. Prior art tapers have been generally high loss and absorb valuable die footprint. In contrast the inventors demonstrate a small low loss waveguide taper designed using a methodology they refer to a “constant loss”.

Abstract: Some embodiments of the present disclosure provide an optical sensor. The optical sensor includes a semiconductive substrate. A light sensing region is on the semiconductive substrate. A waveguide region is configured to guide light from a wave insert portion through a waveguide portion and to a sample holding portion. The waveguide portion includes a first dielectric layer including a first refractive index. A second dielectric layer includes a second refractive index. The second refractive index is smaller than the first refractive index. A first interconnect portion is positioned in the waveguide portion, configured to transmit electrical signal from the light sensing region to an external circuit. The sample holding portion is over the light sensing region.

Abstract: An effective refractive index of a TM0 polarized wave guided through the first core when existing alone and an effective refractive index of a TE0 polarized wave guided through the second core when existing alone are continuous as a function of a distance from a starting point of a side-by-side arrangement section. A magnitude relationship between an effective refractive index of an odd mode of a TE0 polarized wave guided through the side-by-side arrangement section and an effective refractive index of an even mode of a TM0 polarized wave guided through the side-by-side arrangement section is reversed between the starting point and an ending point of the side-by-side arrangement section. A refractive index distribution is vertically asymmetrical in an interaction section. An emission edge surface and an emission edge surface cover an entrance edge surface without excess or deficiency.

Abstract: An adiabatic elliptical optical coupler device is provided comprising: a substrate having an edge; a first waveguide on the substrate, the first waveguide comprising a constant-width region and a tapered region terminating at the edge of the substrate, the tapered region having a smaller width at the edge than at the constant-width region; and, a pair of second waveguides on the substrate, and located on either side of the tapered region, each of the pair of the second waveguides terminating at the edge at a first end and extending to a second end adjacent the constant-width region, and distal the first end; at least a portion of each of the pair of second waveguides being tapered, and optically coupled to the first waveguide to transition a mode of an optical signal in the first waveguide from an elliptical mode at the edge towards a confined mode.

Abstract: A steerable laser probe may include a handle, an actuation lever, an optic fiber, and a housing tube. The housing tube may have a first housing tube portion having a first stiffness and a second housing tube portion having a second stiffness. The second stiffness may be greater than the first stiffness. The optic fiber may be disposed within the housing tube and within an inner bore of the handle. An actuation of the actuation lever about a pivot pin of the handle may gradually curve the optic fiber. An actuation of the actuation lever about the pivot pin of the handle may gradually straighten the optic fiber.

Abstract: A laser system for generating optical pulses at an operating wavelength of the laser system. The system has an optical resonator comprising first and second reflectors, and a tapered optical fiber disposed between the first and second reflectors. The tapered optical fiber has a core which has a tapered input section which tapers from single mode to multimode at the laser operating wavelength, an inner section of substantially constant diameter capable of supporting multiple modes at the laser operating wavelength and a tapered output section which tapers from a first diameter to a second diameter that is smaller than the first diameter.

Abstract: A right angle waveguide having a square rod-type square lattice photonic crystal and a single compensation scattering rod having a high refractive index. The right angle waveguide is a photonic crystal formed from first dielectric rods having a high refractive index arranged in a background dielectric having a low refractive index according to a square lattice. In the photonic crystal, one row and one column of the first dielectric rods having the high refractive index are removed to form the right angle waveguide. A second dielectric rod having a high refractive index is arranged at a corner of the right angle waveguide, the second dielectric rod being the compensation scattering rod. The first dielectric rods are square rods having the high refractive index. The right angle waveguide has extremely low reflectance and a very high transmission rate, and facilitates large-scale optical path integration.

Abstract: A method of fabricating an optical coupling device, comprising forming a waveguide mask layer on a substrate platform, wherein the waveguide mask layer comprises an array of openings comprising a first end and a second end opposite to the first end, immersing the substrate platform into a salt melt comprising ions to form an array of waveguides in the substrate platform through an ion diffusion process, and controlling a rate of immersion such that a diffusion depth of the ions varies as a function of a distance in a direction from the first end to the second end, wherein the array of waveguides extends in the direction from the first end to the second end.

Abstract: Provided is a waveguide mode converter (30) that converts a waveguide mode and that is placed in a transition area (connection section) (43) of a rib-type waveguide (50) and a channel-type waveguide (51). The rib-type waveguide (50) has a tapered section (23b). The tapered section (23b) constitutes a core layer (23) that extends on both sides of a rib (23a) and has a width (Wt) that changes gradually in a direction that is vertical to the waveguide direction.

Abstract: An optical waveguide includes a waveguide core including a first region, a second region having a step at which a thickness varies, and a third region having a thickness smaller than that of the first region. The second region has thick film regions continuing with the first region and positioned at both sides in a widthwise direction. The thick film regions have a thickness that is equal to that of the first region and have a gradually reducing width from the first region side to the third region side. The second region further has a thin film region sandwiched by the thick film regions and continuing with the third region. The thin film region has a thickness equal to that of the third region.

Abstract: A spot size converter may include a tapered periodic segmented waveguide (PSW). The tapered PSW may include a plurality of waveguide segments defined by a plurality of gaps between the plurality of waveguide segments. The plurality of gaps may be at one or more angles that are not substantially parallel to a direction of a width of the tapered PSW. The direction of the width of the tapered PSW may be substantially perpendicular to a direction in which light passes through the tapered PSW.

Abstract: A spectrometer comprises a substrate and a waveguide on the substrate, the waveguide including an elongate part and a tapered input for guiding electromagnetic radiation to the elongate part. The tapered input includes an input end for receiving the electromagnetic radiation and an output end coupled to the elongate part, the input end being wider than the output end. The spectrometer may further comprise a plurality of resonators coupled to the elongate part of the waveguide.

Abstract: An apparatus includes an optical fiber bundle that includes a plurality of input optical fibers and a tapered segment. One end of each of the input optical fibers physically connects to a wide end of the tapered segment. The optical fiber bundle is an integral unit. The input optical fibers are multimode optical fibers. Fundamental optical propagating modes of at least two of the multimode optical fibers have different velocities.

Abstract: A super-oscillatory lens (10) having a pre-defined pattern to spatially modulate the light beam in amplitude and/or phase which has a blocking element (6) formed integrally with the lens, or as a separate component adjacent to the lens, which is opaque to the light beam to cause diffraction of the light beam around the blocking element and formation of a shadow region (20). The lens and blocking element focus the light beam to form an elongate needle-shaped focus (15) in the shadow region (20). In any application in which it is necessary to scan a small spot over a surface, compared with a conventional objective lens focus the elongate shape of the focus relaxes the requirement on a feedback loop to maintain a constant separation between a scan head and a surface being scanned. The elongate shape is also ideal shape for materials processing applications.

Abstract: A two-core optical fiber is provided for use in Brillouin distributed fiber sensor applications and systems. The two-core fiber includes a first and second core. Each core is configured to exhibit a Brillouin frequency shift greater than 30 Mhz relative to the other core. Further, each core possesses temperature and strain coefficients that differ from the other core. The cores can be configured to produce Brillouin frequency shift levels of at least 30 Mhz relative to one another. These differences in shift levels may be effected by adjustment of the material compositions, doping concentrations and/or refractive index profiles of each of the cores. These optical fibers may also be used in BOTDR- and BOTDA-based sensor systems and arrangements.

Abstract: A fiber coupler is provided, which includes a tubular enveloping structure and several optical fibers arranged in the enveloping structure, each of which has a fiber core and a fiber cladding surrounding same, in order to conduct laser radiation, and each of which extends from the first as far as the second end of the enveloping structure. The enveloping structure includes a tapering section which is tapered in a first direction from the first as far as the second end. In the tapering section, both a first ratio of the diameter of the fiber core to the diameter of the fiber cladding and also a second ratio of the diameter of the mode field of the laser radiation conducted in the optical fiber to the diameter of the fiber core, increases in the first direction for each optical fiber.

Abstract: The present disclosure generally relates to a method of optically coupling a photonic integrated circuit and an external optical component.

Abstract: Single mode fiber beam combiners are formed by extending single mode fibers through a glass ferrule, and tapering and fusing the fibers and the ferrule. Tapers can be selected so that optical power input to each of the single mode fibers remains partially guided by the single mode fiber cladding, or is guided by the multimode fiber formed by the glass ferrule and the fused fiber claddings. Such combiners can include double clad fibers or actively doped fibers for use in lasers or amplifiers.

Abstract: An optical coupler includes a plurality of tapers, each of the taper-bases arranged substantially in a first plane to form a base of the optical coupler for connecting to a first optical waveguide, and the taper-tips arranged substantially non-overlapping in a second plane corresponding to a coupling facet for coupling with a second optical waveguide. This multi-taper coupler overcomes the energy loss of conventional techniques, allowing optical coupling between a variety of optical devices including optical fibers, waveguides, diodes, and switches. The multi-taper has increased information transmission efficiency, reduced loss of signal strength between coupled products, and is more robust to damage of the coupler, and the coupling area is larger than conventional couplers thereby reducing coupling complexity and increasing coupling probability.

Abstract: An integrated optical coupling device may include a substrate, a coating layer disposed on the substrate, and a prism disposed on the coating layer. The prism may include a first surface and a second surface. The integrated optical coupling device may also include a first lens disposed on the first surface of the prism, a second lens disposed on the second surface of the prism, and an anti-reflection coating layer disposed on the first lens and the second lens.

Abstract: A waveguide comprises an annular cross-section and a first numerical aperture (NA) at one end. The waveguide further comprises either an annular or circular cross-section at the other end, which has a second NA. The waveguide has a progressively-varying NA, which varies from the first NA (at one end) to the second NA (at the other end).

Abstract: A beam combiner is disclosed that comprises a planar lightwave circuit that is based on undoped silicon nitride-based surface waveguides, wherein the planar lightwave circuit comprises a plurality of input ports, a mixing region, and an output port, and wherein the mixing region comprises a plurality of directional couplers that are arranged in a tree structure. Embodiments of the present invention are capable of combining a plurality of light signals characterized by disparate wavelengths on irregular spacings with low loss. Further, the present invention enables high-volume, low cost production of beam combiners capable of combining three or more light signals into a single composite output beam.

Abstract: A semiconductor optical device including: a substrate including a first region and a second region; a first optical waveguide disposed on the first region, the first optical waveguide including a core layer and a cladding layer disposed on the core layer, the cladding layer including a first cladding region and a semiconductor layer disposed on the first cladding region, the first optical waveguide extending from an end facet of the semiconductor optical device to a boundary between the first region and the second region; a second optical waveguide disposed on the second region; and a region disposed on the cladding layer, the region having a lower refractive index than that of the first cladding region. The semiconductor layer has a higher refractive index than that of the first cladding region. The thickness of the core layer monotonically increases from the end facet toward the boundary.

Abstract: The present invention provides a backlight module and a display device. The present invention can solve the problem that a hot spot in a marginal portion of a light guide plate results in non-uniform brightness of emitted light from a backlight module. The backlight module comprises a light guide plate and a plurality of light sources, the light guide plate comprising a light incident surface, the plurality of light sources being arranged opposite to the light incident surface of the light guide plate. The backlight module further comprises a light scattering unit arranged between the plurality of light sources and the light incident surface of the light guide plate, and the light scattering unit is used for scattering and irradiating light rays from the plurality of light sources to the light guide plate. The display device of the present invention comprises the backlight module as described above.

Abstract: Some embodiments of the present disclosure relate to an infrared (IR) opto-electronic sensor having a silicon waveguide implemented on a single silicon integrated chip. The IR sensor has a semiconductor substrate having a silicon waveguide extends along a length between a radiation input conduit and a radiation output conduit. The radiation input conduit couples radiation into the silicon waveguide, while the radiation output conduit couples radiation out from the silicon waveguide. The silicon waveguide conveys the IR radiation from the radiation input conduit to the radiation output conduit at a single mode. As the radiation is conveyed by the silicon waveguide, an evanescent field is formed that extends outward from the silicon waveguide to interact with a sample positioned between the radiation input conduit and the radiation output conduit.

Abstract: An optical combiner includes a plurality of input optical fibers, an output optical fiber, and a bridge fiber optically coupled to the plurality of input optical fibers and the output optical fiber. The bridge fiber includes a tapered portion whose outer diameter is reduced toward the emission end, and the outer diameter of the emission end face of the bridge fiber is smaller than the cladding outer diameter of the incident end face of the output optical fiber.

Abstract: Provided is an optical fiber assembly with which flexibility in the vicinity of an alignment member can be maintained, as well as a method for manufacturing this optical fiber assembly, and an optical probe which uses this optical fiber assembly. This optical fiber assembly is equipped with: multiple optical fibers (11, 12); an alignment member (10) that aligns and holds these multiple optical fibers (11, 12); a first adhesion part (20) where the alignment member (10) and the multiple optical fibers (11, 12) are adhered by means of a first adhesive agent having curability; and a second adhesion part (21) where the multiple optical fibers (11, 12) are adhered to each other within a prescribed distance from the rear end of the alignment member (10) by means of a second adhesive agent that cures while having greater flexibility than the first adhesive agent.

Abstract: An apparatus comprising a first optical input coupler, having first and second input ports and first and second output ports. The optical input coupler can be configured to receive an optical input signal to the first input port. An optical power level ratio of a second optical output to first optical output transmitted from the second and the first output ports, respectively, equals about 2:1.

Abstract: Mode size converter including an overlay waveguide having an input end configured to receive light from an optical element. The overlay waveguide has a first refractive index. The mode size converter also includes a signal waveguide that is embedded within the overlay waveguide and has a second refractive index that is greater than the first refractive index. The signal waveguide includes first and second arm segments and a stem segment that form a Y-junction. The first and second arm segments are configured to reduce a modal profile of the light propagating toward the stem segment from the input end of the overlay waveguide. Each of the first and second arm segments has a distal end and a pair of opposite side edges, wherein the pair of side edges extend parallel to each other between the corresponding distal end and the stem segment.

Abstract: A steerable laser probe may include a handle having a handle distal end and a handle proximal end, an auto-fixing actuation control, a housing tube having a housing tube distal end and a housing tube proximal end, a first housing tube portion having a first stiffness, a second housing tube portion having a second stiffness, and an optic fiber disposed within an inner bore of the handle and the housing tube. An actuation of the auto-fixing actuation control may gradually curve the housing tube. A gradual curving of the housing tube may gradually curve the optic fiber.

Abstract: A system for chromatic dispersion compensation is presented. The system includes an optical splitting element, a plurality of optical elements, and a plurality of waveguides. The optical splitting element is configured to generate at least a first beam of radiation and a second beam of radiation. The plurality of optical elements is configured to identify one or more optical paths amongst a plurality of optical paths for the first beam of radiation to travel. One of the plurality of waveguides disposed in one of the plurality of optical paths has group delay and dispersion coefficient properties per unit length that are different from group delay and dispersion coefficient properties per unit length of another one of the plurality of waveguides disposed in another one of the plurality of optical paths. The group delay and dispersion coefficient properties per unit length compensate for a chromatic dispersion associated with the second beam of radiation.

Abstract: A method of forming a wave guide for a heat assisted magnetic recording slider of a disk drive includes depositing a layer of waveguide material onto a substrate, and depositing a layer of a hard mask material onto the waveguide material. The method then includes depositing a layer of photoresist onto the hard mask material, and exposing the photoresist to produce a hard mask pattern that includes a waveguide pattern. The method also includes stripping the photoresist material leaving the hard mask pattern having a first line edge roughness. The method also includes removing the waveguide material not covered by the hard mask, the waveguide having sidewalls which having a line edge roughness which is substantially equal to the first line edge roughness. Also disclosed is an apparatus for accomplishing the method.

Abstract: A low mode beam combiner (10) including individual entry fibers (12) that maintain a low mode operation, an exit fiber (16), and a spliced section (14) including a bundle of spliced entry fibers (12), in which a bundle diameter is reduced to a LMA (large mode area) core of the exit fiber (16).

Abstract: A method for manufacturing a semiconductor optical device includes the steps of growing a stacked layer including lower and upper core layers, a first upper region including a non-doped layer, a second upper region including a p-type layer, and a cap layer; forming an upper mesa by etching the stacked layer; selectively etching the cap layer in the upper mesa on the first and second regions; forming a mask on the upper mesa in the second and third regions; and etching the upper mesa using the mask so as to form first to fourth mesa portions. The first and fourth mesa portions are formed by etching the first and second upper regions, and the second upper region and the cap layer, respectively. The second and third mesa portions are formed by etching the first and second upper regions, and the second upper region and the cap layer, respectively.

Abstract: A multiwavelength laser-based intense light source is described having applications in incision, excision and ablation of soft tissues with minimal collateral tissue damage. The light source combines the output of a plurality of relatively low power laser sources, emitting radiation in the region of the electromagnetic spectrum bounded by approximately 350 nm to 450 nm, where the combined output may be coupled into a single fiber optic energy delivery device: a standard surgical probe. Spectral and spatial beam combining are used to produce an incoherent light source with relatively low average power at any given wavelength, but with high total power and superior M2 beam quality, targeting multiple chromophores in target tissue and tissue breakdown product chromophores for consistently high and target absorption without indiscriminant char interference throughout a surgical procedure.

Abstract: Systems that include an energy source configured to provide transverse electric (TE) mode energy; a channel waveguide configured to receive energy from the energy source, the channel waveguide having at least one mirror plane; and a near field transducer (NFT) configured to receive energy from the channel waveguide, the NFT having at least one mirror plane.

Abstract: A high power fiber laser system is configured with a combiner end fiber spliced to a combiner output fiber. The system further includes a light stripper extending along the combiner end and output fibers and configured with sequentially located zones which are provided with respective refractive indices. In a forward propagating direction of light signal, the upstream zone includes polymeric material with the refractive index higher than that of the cladding of the combiner end fiber. This zone is configured to remove the backreflected core guided light bled into the cladding of the combiner through a splice between combiner end and output fibers. The intermediate zone includes polymeric material configured with a refractive index lower than that of the cladding of the combiner output fiber so it can prevent clad guided signal light from decoupling the cladding under the material.

Abstract: Embodiments of the present invention generally relate to laser combiners, and more specifically, to all-fiber devices that combine optical laser power from multiple separate sources such as lasers or amplifiers. In one embodiment, a method of manufacturing a combiner device comprises: positioning an plurality of fibers into a bundle of fibers; drawing the bundle of fibers to create a tapered section, the tapered section having a first outer diameter at an input end, a second outer diameter at an output end, and a taper ratio of at least three; wherein at least one of the fibers of the bundle of fibers comprises an optical waveguide configured for propagating an optical mode from the input end to the output end, and wherein a mode field diameter of the optical mode at the input end is substantially the same as the mode field diameter at the output end.

Abstract: A holographic mirror 10 for re-directing an optical signal that includes a base 14 having an outer surface 16, and a plurality of discrete nano-structures 12 formed into the outer surface of the base. Each nano-structure has an out-of-plane dimension 20 that is within an order of magnitude of one or both in-plane dimensions 22. The plurality of nano-structures are configured in a repeating pattern with a predetermined spacing 18 between nano-structures for re-directing an optical signal.

Abstract: A computed radiography system includes a stimulating light source, a imaging plate (IP), a light collector having a bundle of optical fibers, a light detector, a mechanism providing relative movement in two orthogonal directions between the IP and the stimulating light source while maintaining the perpendicular relationship between the IP and the stimulating light, and a mechanism including an analog to digital converter for converting the collected and detected PLL to a diagnostic readout.

Abstract: The terahertz-wave connector includes: a 2D-PC slab; lattice points periodically arranged in the 2D-PC slab, the lattice points for diffracting the THz waves in PBG frequencies of photonic band structure of the 2D-PC slab in order to prohibit existence in a plane of the 2D-PC slab; a 2D-PC waveguide disposed in the 2D-PC slab and formed with a line defect of the lattice points; and an adiabatic mode converter disposed at the edge face of the 2D-PC slab to which the 2D-PC waveguide extended, the 2D-PC waveguide extended to the adiabatic mode converter. There is provided also the THz-wave IC to which such a terahertz-wave connector is applied.

Abstract: A microresonator structure comprises a waveguide and a microsphere. The waveguide is of elongated cylindrical shape and includes a first section of optical transmission material and a cavity section axially aligned with the first section. The cavity section includes a first cavity and a second cavity. The first cavity is adjacent to the first section and includes a first sidewall of optical transmission material with an inner surface that tapers inward to an apex positioned adjacent to the first section. The second cavity is positioned adjacent to the first cavity of hollow cylindrical shape and includes a circumferential second sidewall of optical transmission material that abuts the first sidewall. The microsphere has a spherical outer surface and is positioned within the cavity section such that the outer surface contacts a portion of the first sidewall and a portion of the second sidewall.

Abstract: The present invention provides a waveguide coupler configured to optically couple a strip waveguide to a first slot photonic crystal waveguide, wherein the slot photonic crystal waveguide has a lattice constant, an air hole diameter, a slot width and a first line defect waveguide width. The waveguide coupler includes a group reflective index taper having a second slot photonic crystal waveguide disposed between and aligned with the first slot photonic crystal waveguide and the strip waveguide. The second slot photonic crystal waveguide has a length, the lattice constant, the air hole diameter, the slot width, and a second line defect waveguide width that is substantially equal to the first line defect waveguide width adjacent to the first slot photonic crystal waveguide and decreases along the length of the second photonic crystal waveguide.

Abstract: An ultra-high power fiber laser system includes a multimode combiner which is configured with a plurality of low mode fibers bundled together and tapering toward its downstream end. A clad mode absorber extends along the tapered downstream end and over a portion of the combiner's output fiber. The absorber is configured with adjacent zones which are provided with respective refractive indices. In a forward propagating direction of signal, the upstream zone includes polymeric material with the refractive index higher than that of the cladding of the combiner end fiber. The intermediate zone includes polymeric material configured with a refractive index lower than that of the cladding of the combiner output fiber. The downstream zone is configured with polymeric material having a refractive index lower than that of the cladding of the combiner output fiber and impregnated with a plurality of light diffusers.

Abstract: A coupling arrangement according to the present invention comprises a target fiber, at least one feeding fiber and an intermediate fiber. The intermediate fiber comprises an input end and a converging taper portion, wherein the input end of the intermediate fiber is spliced to an output end of the feeding fiber in an axial way. Due to this coupling electromagnetic radiation being fed through the feeding fiber enters the intermediate fiber through its input end surface. The converging taper portion of the intermediate fiber is fused to the target fiber in the transfer region in a non-axial way. This leads to a non-axial coupling such that electromagnetic radiation, which entered the intermediate fiber through the input end surface thereof, is coupled into the target fiber.

Abstract: Disclosed are systems and methods for improving the performance of systems for generating and detecting electromagnetic radiation at terahertz (THz) frequencies. Embodiments of the systems and methods include the fabrication and use of coupling tapers to provide efficient transfer of THz radiation between a photomixer and a waveguide that supports a propagating THz mode. A representative system comprises of a photomixer to convert high-frequency components of an optical pump signal into corresponding electrical THz frequencies, a waveguide that supports a propagating THz mode, and a matching taper that effectively converts the highly localized currents generated by the photomixer to the mode supported by the waveguide.

Abstract: Disclosed are an optical waveguide platform with integrated active transmission device and monitoring photodiode. The optical waveguide platform with hybrid integrated optical transmission device and optical active device includes an optical waveguide region formed by stacking a lower cladding layer, a core layer and an upper cladding layer on a substrate; a trench region formed by etching a portion of the optical waveguide region; and a spot expanding region formed on the core layer in the optical waveguide region, in which the optical transmission device is mounted in the trench region and the optical active device is flip-chip bonded to the spot expanding region. The monitoring photodiode is flip-chip bonded to the spot expanding region of the core layer of the optical waveguide, thereby monitoring output light including an optical coupling loss that occurs during flip-chip bonding.

Abstract: A fibre coupler is provided, which includes a tubular enveloping structure and several optical fibres arranged in the enveloping structure, each of which has a fibre core and a fibre cladding surrounding same, in order to conduct laser radiation, and each of which extends from the first as far as the second end of the enveloping structure. The enveloping structure includes a tapering section which is tapered in a first direction from the first as far as the second end. In the tapering section, both a first ratio of the diameter of the fibre core to the diameter of the fibre cladding and also a second ratio of the diameter of the mode field of the laser radiation conducted in the optical fibre to the diameter of the fibre core, increases in the first direction for each optical fibre.