Abstract: A routing integrated circuit element is disclosed. The routing integrated circuit element is connected between a first and a second electronic module and includes a body, a first, and a second buffer element. A first side of the body is connected to the first electronic module. A second side is connected to the second electronic module and located on a different side from the first side. The distance between the second side and the second electronic module is shorter than the distance between the second side and the first electronic module. The first buffer element transmits an electronic signal from the first side to the second side. The second buffer element transmits the electronic signal from the second side to the first side, wherein the transmission directions of the electronic signals transmitted by the first buffer element and the second buffer element are opposite.

Abstract: The present technology can be used to control the current injection profile in the longitudinal direction of a high-power diode laser in order to optimize current densities as a function of position in the cavity to promote higher reliable output power and increase the electrical to optical conversion efficiency of the device beyond the level which can be achieved without application of this technique. This approach can be utilized, e.g., in the fabrication of semiconductor laser chips to improve the output power and wall plug efficiency for applications requiring improved performance operation.

Abstract: A bimodal linear polyethylene composition, products made therefrom, methods of making and using same, and articles containing same.

Abstract: A laser device based on silicon photonics with an in-cavity power monitor includes a gain chip mounted on a silicon photonics substrate and configured to emit light in an active region bounded between a frontend facet with low reflectivity and a backend facet with anti-reflective characteristics. The laser device further includes a wavelength tuner formed with waveguides in the silicon photonics substrate optically coupled to the backend facet to receive light from the gain chip and configured to have a reflector with high reflectivity to reflect the light in an extended cavity formed with the frontend facet through which a laser with a tuned wavelength and amplified power is outputted. Additionally, the laser device includes a photodiode formed in the silicon photonics substrate and coupled to the waveguides in the extended cavity right in front of the reflector to measure power of light thereof.

Abstract: An amplified spontaneous emission, ASE, source device combining a superluminescent light emitting diode, SLED, with a semiconductor optical amplifier, SOA, the SLED and SOA being arranged in series so that the SLED acts as a seed and the SOA acts as a broadband amplifier for the SLED output. Both SLED and SOA have a structure made up of a succession of epitaxial semiconductor layers which form a waveguide comprising a core of active region layers and surrounding cladding layers. The SLED and SOA confinement factors of the SLED and SOA, wherein confinement factor is the percentage of the optical mode power in the active region layers, is designed so that the SLED confinement factor is greater than that of the SOA by at least 20%. This allow higher power outputs, because the SLED power limits imposed by the onset of non-linear effects and catastrophic optical damage can be circumvented.

Abstract: A method for wireless communication in a reflective environment includes (a) receiving first wireless signals at a first antenna assembly at least partially via a first reflective environment, (b) generating a first electrical signal from a first antenna element of the first antenna assembly in response to the first wireless signals, the first antenna element having a first polarization, (c) generating a second electrical signal from a second antenna element of the first antenna assembly in response to the first wireless signals, the second antenna element having a second polarization different from the first polarization, (d) shifting phase of at least one of the first electrical signal and the second electrical signal, and (e) after shifting phase, combining at least the first electrical signal and the second electrical signal to generate a combined electrical signal.

Abstract: An optical receiver can implement a transimpedance amplifier (TIA) to process received light using a closed loop optical pre-amplification. The optical receiver can use an average input value of the TIA to control an semiconductor optical amplifier (SOA) or pre-amplification as received average signal varies. The optical receiver can include a gain controller for the TIA that can measure the TIA swing to adjust the gain of the SOA to pre-amplify received light in a closed loop control configuration.

Abstract: A laser device includes front and back DBRs and an interferometer. The front DBR is coupled to a front DBR electrode. The front DBR forms a first tunable multi-peak lasing filter. The back DBR is coupled to a back DBR electrode. The back DBR forms a second tunable multi-peak lasing filter. The interferometer part is coupled between the front DBR and the back DBR. The interferometer part includes first and second waveguide combiners and first and second interferometer waveguides coupled therebetween. The first waveguide combiner couples the interferometer part to the back DBR. The second waveguide combiner couples the interferometer part to the front DBR. The first interferometer waveguide is coupled to an interferometer electrode. The interferometer forms a third tunable multi-peak lasing filter.

Abstract: Example fiber amplifiers and gain adjustment methods for the fiber amplifiers are described. One example fiber amplifier includes a first power amplifier, a wavelength level adjuster, and a controller, where the first power amplifier is connected to the wavelength level adjuster. The controller includes a first input end and a control output end. The first input end is configured to receive an input optical signal, and the control output end is configured to output a first amplification control signal to the first power amplifier, and output an adjustment control signal to the wavelength level adjuster. The wavelength level adjuster is configured to perform power adjustment on each wavelength in a separate manner based on the adjustment control signal.

Abstract: The present technology can be used to control the current injection profile in the longitudinal direction of a high-power diode laser in order to optimize current densities as a function of position in the cavity to promote higher reliable output power and increase the electrical to optical conversion efficiency of the device beyond the level which can be achieved without application of this technique. This approach can be utilized, e.g., in the fabrication of semiconductor laser chips to improve the output power and wall plug efficiency for applications requiring improved performance operation.

Abstract: A high absorption photovoltaic material and method of making the material for use in a solar cell are disclosed. The photovoltaic material includes a surface modified with a layer of repeating photonic crystal structures. The photonic crystal structures are approximately inverse conically shaped and have a curved sidewall that has an approximately Gaussian shape. The photonic crystal structures generally have a high vertical depth and sidewall angle. The structures also have a gradient refractive index profile and exhibit the parallel-to-interface refraction light trapping effect. An anti-reflective coating is disposed over the photonic crystal structure layer. The photovoltaic material exhibits near unity light absorption over a broad range of visible and near infrared wavelengths and incidence angles, even at reduced thicknesses.

Abstract: Systems and methods are provided for receiving an optical signal from an optical fiber, including: coupling via an optical coupler the optical signal from an optical fiber into first and second waveguides, wherein the optical signal comprises TE and TM polarized optical signals and the optical coupler couples the TE polarized optical signal into the first waveguide and the TM polarized optical signal into the second waveguide; equalizing the TE and TM polarized optical signals from the coupler to equalize optical power levels of the TE and TM polarized optical signals; optically combining the equalized TE and TM polarized optical signals; and transmitting the combined optical signal to a photodetector.

Abstract: An optical transmitter based on optical time division multiplexing is disclosed, which may solve the issues of complex structure and operation of a multilevel-OTDM-based optical transmitter while using a multilevel signal modulation format and OTDM technology that may increase the transmission rate of an optical transmitter with limited bandwidth.

Abstract: A LiDAR system including a laser amplification system is disclosed. The laser amplification system includes a laser source and an optical amplifier. The laser source has a laser cavity and is configured to output electromagnetic radiation. The optical amplifier includes quantum dots and is positioned outside the laser cavity to receive the electromagnetic radiation output from the laser source. The optical amplifier amplifies the received electromagnetic radiation using the quantum dots and outputs the amplified electromagnetic radiation.

Abstract: A MIMO system comprises a remote radio unit (RRU) and central unit. The RRU comprises: a binary phase shift keying (BPSK) modulator, configured to modulate a BPSK waveform by a local oscillator (LO) signal to generate a stimulus signal, wherein the LO signal is derived from a downlink optical signal received via downlink radio over fiber (DL-ROF) from a central unit (CU); and an optical signal generator, in particular a laser, configured to generate an uplink optical signal based on the stimulus signal for transmission via uplink radio over fiber (UL-ROF) to the CU.

Abstract: This application provides a full-duplex self-interference weakening method and a full-duplex self-interference weakening system. The full-duplex self-interference weakening method includes: separately receiving, by a first port of a dual-polarized receive antenna and a second port of the dual-polarized receive antenna, a signal sent by a transmit antenna and adjusting and combining the signal received by the first port of the dual-polarized receive antenna and/or the signal received by the second port of the dual-polarized receive antenna, to weaken interference caused by the transmit antenna to the dual-polarized receive antenna. The full-duplex self-interference weakening method and the full-duplex self-interference weakening system provided in this application resolve a problem that a quantity of antennas and an antenna location are limited in an existing antenna interference cancelation method.

Abstract: In one embodiment, a lidar system includes a light source configured to emit (i) local-oscillator light and (ii) pulses of light, where each emitted pulse of light is coherent with a corresponding portion of the local-oscillator light. The light source includes a seed laser configured to produce seed light and the local-oscillator light. The light source also includes a pulsed optical amplifier configured to amplify temporal portions of the seed light to produce the emitted pulses of light, where each amplified temporal portion of the seed light corresponds to one of the emitted pulses of light. The lidar system also includes a receiver configured to detect the local-oscillator light and a received pulse of light, the received pulse of light including light from one of the emitted pulses of light that is scattered by a target located a distance from the lidar system.

Abstract: A method for reducing nonlinear frequency shifts and suppressing stimulated Brillouin scattering (SBS) in a fiber laser amplifier system. The method includes providing a seed beam having a certain wavelength and frequency modulating the seed beam with an RF waveform to spectrally broadening the seed beam, where the RF waveform is a relatively slow-speed waveform having a large modulation depth. The method also includes amplifying the frequency modulated seed beam with an amplifier having a large nonlinear phase shift and exhibiting frequency modulation (FM) to amplitude modulation (AM) conversion, where the modulation depth is much larger than the nonlinear phase shift of the amplifier.

Abstract: A laser device (1) includes: a branch waveguide (23) configured to split light propagating from an optical amplifier (10) into a plurality of light beams and output the plurality of light beams; a multi-core waveguide (27) including a plurality of waveguide cores (24 to 26) configured to carry the plurality of light beams input from the branch waveguide (23); and a light reflector (31) optically coupled to a light input/output end of the multi-core waveguide (27). The waveguide cores (24 to 26) are configured to extend along the same direction, and placed in proximity to one another to enable optical coupling between adjacent waveguide cores of the waveguide cores (24 to 26).

Abstract: In various embodiments, a metamaterial structure antenna may comprise: a feed line for feeding a signal; a ground plane comprising a cross-shaped aperture forming circular polarization on the basis of a magnetic field induced by the fed signal; and a patch plane formed parallel to the ground plane which emits electromagnetic waves on the basis of the circular polarization.

Abstract: A device and a method to produce an augmented-laser (ATLAS) comprising a bi-stable resistive system (BRS) integrated in series with a semiconductor laser. The laser exhibits reduction/inhibition of the Spontaneous Emission (SE) below lasing threshold by leveraging the abrupt resistance switch of the BRS. The laser system comprises a semiconductor laser and a BRS operating as a reversible switch. The BRS operates in a high resistive state in which a semiconductor laser is below a lasing threshold and emitting in a reduced spontaneous emission regime, and a low resistive state in which a semiconductor laser is above or equal to a lasing threshold and emitting in a stimulated emission regime. The BRS operating as a reversible switch is electrically connected in series across two independent chips or on a single wafer. The BRS is formed using insulator-to-metal transition (IMT) materials or is formed using threshold-switching selectors (TSS).

Abstract: An optical device comprises a light input, a light modulating means and a light output. The optical device further comprises an optical amplification device arranged to amplify light travelling between said light modulating means and said output. The optical amplification device comprises first and second serially connected post SOA (Semiconductor Optical Amplifier) units, each comprising at least one respective serially connected post SOA segment, which device is arranged to vary a light amplification by varying respective SOA bias voltages across said post SOA segments. A total SOA length of the first post SOA unit is relatively longer than a total SOA length of the second post SOA unit, which is relatively shorter. The optical device is arranged to, during operation using a particular operation program, always keep respective SOA bias voltages across each of the post SOA segments of the first post SOA unit at +0.5 V or more.

Abstract: An optical add/drop multiplexer (OADM) includes a drop signal separator and a drop signal reflector. The drop signal separator is coupled to a main input end and a drop end. The drop signal separator is coupled to the drop signal reflector, and the drop signal reflector is coupled to a main output end.

Abstract: A laser medium unit includes: a plate-shaped laser gain medium which includes a first surface and a second surface opposite to the first surface and generates emission light by the irradiation of excitation light from the first surface; a reflection member that is provided on the second surface so as to reflect the excitation light and the emission light; and a cooling member that cools the laser gain medium. The laser gain medium includes an irradiation area which is irradiated with the excitation light and an outer area which is located outside the irradiation area when viewed from a thickness direction intersecting the first surface and the second surface. The cooling member is thermally connected to the second surface through the reflection member so that a cooling area of the laser gain medium is formed on the second surface.

Abstract: A semiconductor laser (1) emits laser light. An electro-absorption optical modulator (2) modulates the laser light. The electro-absorption optical modulator (2) includes a plurality of electro-absorption regions (2a, 2b, 2c) having different extinction characteristics, whereby the extinction ratio curve of the optical device can be controlled to have a shape with multiple steps that is suited to driving conditions.

Abstract: In one embodiment, a lidar system includes a light source configured to emit an optical signal. The light source includes a seed laser diode configured to produce a seed optical signal and a semiconductor optical amplifier (SOA) configured to amplify the seed optical signal to produce an amplified seed optical signal, where the emitted optical signal includes the amplified seed optical signal. The lidar system also includes a scanner configured to direct the emitted optical signal into a field of regard of the lidar system and a receiver configured to detect a portion of the emitted optical signal scattered by a target located a distance from the lidar system. The lidar system further includes a processor configured to determine the distance from the lidar system to the target.

Abstract: An optical device that includes: a base layer; a first region supported by the base layer, the first region including a first plurality of quantum-confined nanostructures and having a first density of quantum-confined nanostructures; a second region supported by the base layer, the first and second regions being non-overlapping regions, the second region having a second density of quantum-confined nanostructures lower than the first density; and an optical confinement structure supported by the base layer and configured to guide at least one transverse optical mode between a first end and a second end of the optical confinement structure. The first region substantially overlaps with the at least one transverse optical mode, and the first density varies across a cross-section of the optical device.

Abstract: A laser medium unit includes: a plate-shaped laser gain medium which includes a first surface and a second surface opposite to the first surface and generates emission light by the irradiation of excitation light from the first surface; a reflection member that is provided on the second surface so as to reflect the excitation light and the emission light; and a cooling member that cools the laser gain medium. The laser gain medium includes an irradiation area which is irradiated with the excitation light and an outer area which is located outside the irradiation area when viewed from a thickness direction intersecting the first surface and the second surface. The cooling member is thermally connected to the second surface through the reflection member so that a cooling area of the laser gain medium is formed on the second surface.

Abstract: A multi-channel laser source, including: a bus waveguide coupled, at an output end of the bus waveguide, to an output of the multi-channel laser source; a first semiconductor optical amplifier; a first back mirror; a first wavelength-dependent coupler, having a first resonant wavelength, on the bus waveguide; a second semiconductor optical amplifier; a second back mirror; and a second wavelength-dependent coupler, on the bus waveguide, having a second resonant wavelength, different from the first resonant wavelength. In some embodiments the first semiconductor optical amplifier is coupled to the bus waveguide by the first wavelength-dependent coupler, which is nearer to the output end of the bus waveguide than the second wavelength-dependent coupler, the second semiconductor optical amplifier is coupled to the bus waveguide by the second wavelength-dependent coupler, and the first wavelength-dependent coupler is configured to transmit light, at the second resonant wavelength, along the bus waveguide.

Abstract: A structure can include a III-N layer with a first lattice constant, a first rare earth pnictide layer with a second lattice constant epitaxially grown over the III-N layer, a second rare earth pnictide layer with a third lattice constant epitaxially grown over the first rare earth pnictide layer, and a semiconductor layer with a fourth lattice constant epitaxially grown over the second rare earth pnictide layer. A first difference between the first lattice constant and the second lattice constant and a second difference between the third lattice constant and the fourth lattice constant are less than one percent.

Abstract: The embodiments herein describe a single-frequency laser source (e.g., a distributed feedback (DFB) laser or distributed Bragg reflector (DBR) laser) that includes a feedback grating or mirror that extends along a waveguide. The grating may be disposed over a portion of the waveguide in an optical gain region in the laser source. Instead of the waveguide or cavity being linear, the laser includes a U-turn region so that two ends of the waveguide terminate at the same facet. That facet is coated with an anti-reflective (AR) coating.

Abstract: An optical interconnect device on a silicon substrate is disclosed which includes a trench having two slanted side walls opposite to each other, a number of polymer waveguides formed in the trench, each including a straight portion and two end reflectors formed on the slanted side walls of the trench, a light source and an optical receiver disposed on an insulated layer on the silicon surface outside the trench. Conductive lines are patterned on the insulating layer and connects to the light source and the optical receiver. The light source and the optical receiver are aligned respectively to the two end reflectors of each polymer waveguide such that an optical path is formed from the light source device through the plurality of polymer waveguides to the optical receiver device, via reflection by the two end reflectors. A fabrication method to build the device is disclosed thereof.

Abstract: A SOI bent taper structure is used as a mode convertor. By tuning the widths of the bent taper and the bend angles, almost lossless mode conversion is realized between TE0 and TE1 in a silicon waveguide. The simulated loss is <0.05 dB across C-band. This bent taper can be combined with bi-layer TM0-TE1 rotator to reach very high efficient TM0-TE0 polarization rotator. An ultra-compact (9 ?m) bi-layer TM0-TE1 taper based on particle swarm optimization is demonstrated. The entire TM0-TE0 rotator has a loss <0.25 dB and polarization extinction ratio >25 dB, worst-case across the C-band.

Abstract: The present disclosure provides a backlight module, which includes at least one quantum wire unit. The at least one quantum wire unit is configured to have an effective wire width such that the at least one quantum wire unit is capable of converting electric energy to emit light of a selected wavelength. Each of quantum wire unit comprises a first electrode, disposed on a first side of a substrate layer; a first buffer layer, disposed on a second side of the substrate layer; an active layer, disposed over the first buffer layer; a second buffer layer, disposed over the active layer; and a second electrode disposed over the second buffer layer. Each quantum wire unit, along with the substrate layer, forms a quantum wire laser generator, which is configured such that the active layer emits light upon application of a voltage difference between the first electrode and the second electrode.

Abstract: The invention relates to a laser diode (10) which has at least one active layer (12) which is arranged within a resonator (14) and is operatively connected to a outcoupling element (16), and further at least one contact layer (18) for coupling charge carriers into the active layer (12), wherein the resonator (14) comprises at least a first section (20) and a second section (22), wherein the second section (22) comprises a plurality of separate resistor elements (24) having a specific electrical resistivity greater than the specific electrical resistivity of the regions (26) between adjacent resistor elements (24), wherein a width (W3) of the resistor elements (24) along a longitudinal axis (X1) of the active layer (12) is less than 20 ?m, and a projection of the resistor elements (24) on the active layer (12) along the first axis (Z1) overlap with at least 10% of the active layer (12).

Abstract: There is provided a semiconductor light-emitting device including a light-emitting edge, an opposite edge, and a first conductive layer that includes a current narrowing structure having a longitudinal direction along one direction from the opposite edge to the light-emitting edge. An active layer is between the first conductive layer and a second conductive layer which respectively come into contact with the first conductive layer and the second conductive layer. The current narrowing structure includes a spread area such that a width of the spread area in a direction along a surface of the first conductive layer widens from a predetermined position toward the light-emitting edge in the one direction. The first electrode layer includes an electrode area on at least the spread area such that a width thereof in the direction along the surface of the first conductive layer becomes smaller than the width of the spread area.

Abstract: An optical waveguide may include a silicon portion and a silicon nitride portion positioned over the silicon portion. The silicon portion may include a taper that decreases a width of the silicon portion. The optical waveguide may include a transition between a loaded single mode or multimode waveguide to a single mode waveguide. The silicon nitride portion may confine optical signals traveling through the optical waveguide in the silicon portion.

Abstract: A ternary superlattice structure includes a substrate and periodic layer structure on the substrate and having alternating infrared absorbing semiconductor materials having a first layer of InAs[1-x]Sb[x] ternary alloy material, and a second layer of In[1-y]Z[y]As ternary alloy material, wherein Z is Ga or Al, wherein x is in a range of greater than zero and less than one, wherein y is in a range of greater than zero and less than one, and wherein a thickness of each of the first and second layers are substantially similar and configured to absorb light in a predetermined spectral band and prevent trapping of carriers in any particular layer. In examples, y is in a range from about 0.05 to about 0.35, and x is in a range of about 0.2 to about 0.8.

Abstract: A light source device includes a light source that generates incoherent light, and an optical amplifier having gain characteristics indicating a gain at each wavelength, which receives the incoherent light output by the light source as input light, and outputs amplified light obtained by amplifying the input light, and a central wavelength of an intensity distribution indicating an intensity at each wavelength of the input light is a wavelength longer than a central wavelength of the gain characteristics indicating a gain at each wavelength of the optical amplifier.

Abstract: Methods and apparatus for spectral narrowing and wavelength stabilization of broad-area lasers, such as an apparatus including a broad-area laser source configured to emit light along an emission axis in an emission pattern extending along the emission axis, and a single-mode fiber Bragg grating, such as a single-mode core incorporating a fiber Bragg grating embedded in a core of a dual-clad fiber, the single-mode fiber Bragg grating configured to spectrally selectively reflect back light from a sub-aperture portion of the emitted light to the broad-area laser source. The single mode core having the FBG is off-axis in comparison to the central axis of the double-clad fiber and allows for frequency stabilization of the broad area laser diode output improving its performance as pump laser for a doped fiber amplifier.

Abstract: A SOI bent taper structure is used as a mode convertor. By tuning the widths of the bent taper and the bend angles, almost lossless mode conversion is realized between TE0 and TE1 in a silicon waveguide. The simulated loss is <0.05 dB across C-band. This bent taper can be combined with bi-layer TM0-TE1 rotator to reach very high efficient TM0-TE0 polarization rotator. An ultra-compact (9 ?m) bi-layer TM0-TE1 taper based on particle swarm optimization is demonstrated. The entire TM0-TE0 rotator has a loss <0.25 dB and polarization extinction ratio >25 dB, worst-case across the C-band.

Abstract: A three dimensional optical interconnect device having one input and multiple output ports mounted on the same surface of a SOI wafer is disclosed. The first Si surface has a silicon waveguide with a straight portion, a first and a second 45 degree end reflectors and multiple optical splitters arranged in a sequence along the straight portion. The second silicon surface has an insulating layer and an active optical input device (VCSEL laser) and multiple receiver ports mounted on the insulating layer. The first end reflector is aligned to the input optical device, the optical splitters and the second end reflector are sequentially aligned to the photodetectors respectively. Multiple optical paths are formed from the input optical device to each of photodetectors by a reflection from each aligned optical splitter and a reflection from the second end reflector through the silicon substrate.

Abstract: An optical circuit module comprises a substrate with a first optical coupler connected to a first optical waveguide and a second optical coupler connected to a second optical waveguide on a substrate surface side; and a semiconductor photonic device mounted on the substrate, wherein the semiconductor photonic device has a third optical waveguide and a fourth optical waveguide extending to a first end face that faces the substrate surface, and wherein the third optical waveguide is optically connected to the first optical coupler and the fourth optical waveguide is optically connected to the second optical coupler.

Abstract: The present invention relates to an optical light guide element having a first end section with a light entrance area designed for facing a light source and having a second end section with a light exit area designed for facing a light target area, wherein the light exit area is defined by a second surface area on the optical light guide element which faces a light target area, and wherein the light entrance area is defined by a first surface area on the optical light guide element which faces the light source, wherein the first end section comprises a first inclined surface area which forms an acute angle with the first surface area of the light entrance area, wherein the second end section forms a second inclined surface area which encloses an acute angle with the surface area of the light exit area, characterized in that said first surface area on the optical light guide element which faces the light source comprises a first replicated polymer lens.

Abstract: A semiconductor device includes an array of VCSEL devices with an annealed oxygen implant region (annealed at a temperature greater than 800° C.) that surrounds and extends laterally between the VCSEL devices. A common anode and a common cathode can be electrically coupled to the VCSEL devices, with the common anode overlying the annealed oxygen implant region. The annealed oxygen implant region can funnel current into active optical regions of the VCSEL devices and provide current isolation between the VCSEL devices while avoiding an isolation etch between VCSEL devices. In another embodiment, a semiconductor device includes an annealed oxygen implant region surrounding a VCSEL device. The VCSEL device(s) can be formed from a multi-junction layer structure where built-in hole charge Qp for an intermediate p-type layer relative to built-in electron charge Qn for a bottom n-type layer is configured for diode-like current-voltage characteristics of the VCSEL device(s).

Abstract: Provided is an optical semiconductor element including: a stacked structure body 20 formed of a first compound semiconductor layer 21, a third compound semiconductor layer (active layer) 23, and a second compound semiconductor layer 22. A fundamental mode waveguide region 40 with a waveguide width W1, a free propagation region 50 with a width larger than W1, and a light emitting region 60 having a tapered shape (flared shape) with a width increasing toward a light emitting end surface 25 are arranged in sequence.

Abstract: In the examples provided herein, an apparatus has a mode converter coupled to a first waveguide to convert light propagating in a first set of spatial modes along the first waveguide to a second set of spatial modes. The apparatus also has a second waveguide coupled to the mode converter, where the second set of spatial modes propagate along the second waveguide in a first direction away from the mode converter. Further, the apparatus includes a coupler to couple a portion of the light propagating in the second set of spatial modes out of the second waveguide. Additionally, the second waveguide has an end facet away from the mode converter to reduce back reflection of the light not coupled out of the second waveguide to the first waveguide.

Abstract: Provided are a practical rib type optical waveguide in which polarization dependence and wavelength dependence and the like are small and an optical multiplexer/demultiplexer using the same. An optical waveguide type optical multiplexer/demultiplexer of the present invention includes a substrate, M input optical waveguides and N output optical waveguides including a single mode rib type optical waveguide, multi-mode optical interference regions including a rib type optical waveguide, and reversible tapered regions that smoothly connect the input/output optical waveguides to the multi-mode optical interference regions and include M×N rib type optical waveguides, and both side surfaces of the multi-mode optical interference region are respectively formed in a stepped shape.

Abstract: Unidirectionality of lasers is enhanced by forming one or more etched gaps in the laser cavity. The gaps may be provided in any segment of a laser, such as any leg of a ring laser, or in one leg of a V-shaped laser. A Brewster angle facet at the distal end of a photonic device coupled to the laser reduces back-reflection into the laser cavity. A distributed Bragg reflector is used at the output of a laser to enhance the side-mode suppression ratio of the laser.

Abstract: Concatenated distributed feedback lasers having novel waveguides are disclosed. The waveguides allow for coupling of the laser beam between active and passive waveguide structures and improved device design and output efficiency. Methods of making along with methods of using such devices are also disclosed.