Abstract: Provided are a semiconductor optical amplifier and an optical signal processing method using the same. The reflective semiconductor optical amplifier includes: an optical signal amplification region operating to allow a downward optical signal incident from the external to obtain a gain; and an optical signal modulation region connected to the optical signal amplification region and generating a modulated optical signal. The downward optical signal is amplified through a cross gain modulation using the modulated optical signal and is outputted as an upward optical signal.

Abstract: A metamaterial structure is provided, including a substrate and a plurality of resonators that are provided on different surfaces of the substrate or different layers of the substrate. The resonators have resonance characteristics different from each other, and the metamaterial structure has a permittivity, a permeability, and a refractive index respectively different from those of the substrate in a predetermined frequency bandwidth.

Abstract: A semiconductor optical amplifier includes an n-type semiconductor layer, a p-type semiconductor layer an active layer provided between the n-type semiconductor layer and the p-type semiconductor layer, the active layer transmitting an optical signal and a current-injection part that injects current into the active layer via the n-type semiconductor layer and the p-type semiconductor layer, the active layer including a first active layer that includes AlGaInAs, and a second active layer that includes GaInAsP, the second active layer provided closer to an output side than the first active layer, and the first active layer and the second active layer being butt-jointed.

Abstract: An optical switch assembly comprising at least two optical amplifiers (10, 20), means for applying a first input signal to one end of both amplifiers (10, 20) and a second input signal to another end, and means for simultaneously driving one or other of the amplifiers into a saturated state whilst the other is unsaturated such that only the amplifier that is unsaturated provides any significant amplification to the input signals at each end, and means for feeding the amplified output signals from the amplifiers to at least two output nodes such that the two amplifiers (10, 20) are connected to the two output nodes in opposite connections.

Abstract: An optical integration circuit includes a semiconductor optical amplifier (SOA), a readout mechanism coupled to the SOA, and an optical filter coupled to an output of the SOA. The SOA has a decaying response function and an input for receiving an optical input signal having a first wavelength. The SOA is configured to output an optical signal representing a temporal integration of the optical input signal. The readout mechanism provides an optical readout signal having a second wavelength to the SOA for measuring a state of the SOA. The optical filter is configured to receive the signal representing the temporal integration of the optical input signal and block optical signals having the first wavelength.

Abstract: An optical waveform reshaping device, including a semiconductor optical waveguide which has an active layer, wherein: optical amplification regions and optical absorption regions are installed alternately along the semiconductor optical waveguide; one optical amplification region is set longer than the other optical amplification regions so that a desired amplification factor can be obtained when power of an input optical signal is at an ON level; a power level is maintained by the other optical amplification regions excluding the one optical amplification region and by the optical absorption regions when the power of the input optical signal is at the ON level; and when the power of the input optical signal is at an OFF level, the input optical signal is absorbed by the optical absorption regions so that a power level of an output optical signal will not be higher than the power level of the input optical signal.

Abstract: An optical amplifying medium, a method of manufacturing the optical amplifying medium are provided, and an optical device comprising the optical amplifying medium. The optical amplifying medium includes a multi-layer structure in which a first material layer doped with an activator and a second material layer that comprises a sensitizer are stacked.

Abstract: A generation unit generates a polarization multiplexing signal in which two optical signals, each polarization of which is orthogonal to each other, are combined. A detector detects the powers of the two optical signals contained in the polarization multiplexing signal generated by the generation unit. An amplifier amplifies, according to each polarization of the two optical signals contained in the polarization multiplexing signal generated by the generation unit, the powers of the two optical signals. An controller controls a gain of the amplifier with respect to each polarization of the two optical signals so as to reduce difference in the powers of the two optical signals detected by the detector.

Abstract: In accordance with one embodiment of the present disclosure a system for compensating for polarization dependent loss experienced by an optical signal comprises an optical amplifier configured to amplify an optical signal and having a polarization dependent gain (PDG). The system also comprises a polarization rotator coupled to the amplifier and configured to rotate the polarization of the optical signal before the signal enters the amplifier. The system also comprises a polarization dependent loss (PDL) controller coupled to the amplifier and the rotator. The PDL controller may be configured to determine a post-amplifier PDL of the optical signal as the signal leaves the optical amplifier. The PDL controller may also be configured to control the rotator to rotate the polarization of the optical signal based on the post-amplifier PDL, such that the PDG of the amplifier compensates for the PDL experienced by the optical signal.

Abstract: A gain medium and an interband cascade laser, an interband cascade amplifier, and an external cavity laser having the gain medium are presented.

Abstract: A Reflective Semiconductor Optical Amplifier (RSOA) for compensating for light loss in an optical link, an RSOA module for improving polarization dependency using the RSOA, and a Passive Optical Network (PON) for increasing economical efficiency and practical use of a bandwidth using the RSOA are provided. The PON includes a central office comprising a plurality of optic sources transmitting a downstream signal and a plurality of first receivers receiving an upstream signal; at least one optical network terminal (ONT) including a second receiver receiving the downstream signal and an RSOA which receives the downstream signal, remodulates the downstream signal into the upstream signal, and transmits the upstream signal in loopback mode; and a remote node interfacing the central office with the ONT. The upstream signal and the downstream signal are transmitted between the remote node and the ONT via a single optical fiber. The remote node includes an optical power splitter at its port connected to the ONT.

Abstract: In one of the embodiments, a dark channel array is provided which includes gain channels, each configured to emit an output beam from an output surface and to have a light wave propagating therethrough. It further includes a dark channel configured to emit an output beam from the output surface of the dark channel array and to have a light wave propagating in the dark channel, such that output beams from the plurality of gain channels are coherently coupled in phase with each other. The dark channel array is configured such that the dark channel captures a portion of the output beam from at least two of the plurality of gain channels by radiant coupling.

Abstract: An apparatus for monitoring optical equipment in an optical circuit is disclosed in which the apparatus may include an optical device situated to receive an optical input signal and to reflect a portion of the energy of the received optical input signal, thereby providing a reflected input signal; a first photodiode located along a path of the reflected input signal, and operable to receive optical energy from the reflected optical input signal and from ambient optical power; a second photodiode located substantially outside the reflection path of the optical input signal; and means for calculating a magnitude of a power level of the optical input signal from values of outputs from the first and second photodiodes.

Abstract: An optical network unit (10) comprising a reflective semi-conductor optical amplifier (R-SOA) 12 and a driver 14. The R-SOA has a large optical confinement factor and is arranged to receive a portion of a downstream optical signal having a signal wavelength and a signal power. The driver is arranged to generate a drive signal 16 to drive the R-SOA. The drive signal is arranged to cause the R-SOA to operate in saturation at the signal power. The drive signal is further arranged to cause the R-SOA to apply a return-to-zero line code to said portion of the downstream optical signal to form an upstream optical signal at the signal wavelength. The drive signal is further arranged to cause the R-SOA to apply a phase modulation to the upstream optical signal.

Abstract: An optical amplification module has a semiconductor optical amplifier, a package accommodating the semiconductor optical amplifier, and a first connector and a second connector holding respective collimator lenses and arranged in parallel on the package. A sum of bend radii of the first optical fiber and the second optical fiber is greater than a space between the first connector and the second connector.

Abstract: A semiconductor optical amplifier includes: a laminated structure sequentially including a first compound semiconductor layer composed of GaN compound semiconductor and having a first conductivity type, a third compound semiconductor layer having a light amplification region composed of GaN compound semiconductor, and a second compound semiconductor layer composed of GaN compound semiconductor and having a second conductivity type; a second electrode formed on the second compound semiconductor layer; and a first electrode electrically connected to the first compound semiconductor layer. The laminated structure has a ridge stripe structure. When widths of the ridge stripe structure in a light output end face and the ridge stripe structure in a light incident end face are respectively Wout, and Win, Wout>Win is satisfied. A carrier non-injection region is provided in an internal region of the laminated structure from the light output end face along an axis line of the semiconductor optical amplifier.

Abstract: One embodiment of the present method and apparatus encompasses an apparatus that may have: a predetermined length, the self-imaging semiconductor waveguide having first and second opposed sides; quantum wells disposed within the self-imaging semiconductor waveguide along the length of the self-imaging semiconductor waveguide, the quantum wells being formed of a quantum well gain material; microchannel cooler that extends substantially the width of the self-imaging semiconductor waveguide, the microchannel cooler located adjacent the first side of the self-imaging semiconductor waveguide; and a plurality of pump arrays arranged along the microchannel cooler opposed from the first side of the self-imaging semiconductor waveguide; wherein the quantum well gain material is photopumped through the microchannel cooler.

Abstract: A new broadband source having a discrete set of spectral emission lines having high peak power in each line is provided by placing a gain medium in a reflective cavity comprising reflective front and back surfaces. A cavity feedback factor less than unity is achieved by providing reflectivity of one surface substantially lower than the reflectivity of the other surface such that spontaneous emission in the gain medium is linearly amplified just below the lasing threshold. In an alternative arrangement, a movable external back surface placed at a prescribed distance from the gain medium provides a means to achieve a free spectral range and finesse of the emission lines to match a pitch of a detector array in a SD-OCT system. By simultaneously providing high power to each detector element of the array, sensitivity and imaging speed of SD-OCT system are significantly improved.

Abstract: An adjustable optical signal delay module which adjusts power of an amplified spontaneous emission generated by a semiconductor optical amplifier and feeds the adjusted amplified spontaneous emission back to the semiconductor optical amplifier in a direction opposite to an optical signal being amplified by the semiconductor optical amplifier is provided. The feedback of the adjusted amplified spontaneous emission varies a group refractive index of the semiconductor optical amplifier and delays the transmission of an optical signal through the semiconductor optical amplifier. By that arrangement, the adjustable optical delay module obviates the need for the pump laser conventionally required by a coherent population oscillation mechanism. The feedback optical loop includes a variable optical attenuator, an optical filter, and optical circulators. A user can control the delay timing of optical signals via adjusting optical power in the feedback optical loop.

Abstract: A semiconductor optical amplifier includes a semiconductor substrate, a lower cladding layer formed on the semiconductor substrate, a light absorption layer and an optical amplification layer formed on the lower cladding layer, and an upper cladding layer formed on the light absorption layer and the optical amplification layer. The band gap of a semiconductor material that forms the light absorption layer is wider than the band gap of a semiconductor material that forms the optical amplification layer. The difference between the band gap of the semiconductor material that forms the light absorption layer and the band gap of the semiconductor material that forms the optical amplification layer is 0.12 eV or more.

Abstract: A method is provided for optical amplification using a silicon (Si) nanocrystal embedded silicon oxide (SiOx) waveguide. The method provides a Si nanocrystal embedded SiOx waveguide, where x is less than 2, having a quantum efficiency of greater than 10%. An optical input signal is supplied to the Si nanocrystal embedded SiOx waveguide, having a first power at a first wavelength in the range of 700 to 950 nm. The Si nanocrystal embedded SiOx waveguide is pumped with an optical source having a second power at a second wavelength in a range of 250 to 550 nm. As a result, an optical output signal having a third power is generated, greater than the first power, at the first wavelength. In one aspect, the third power increases in response to the length of the waveguide strip.

Abstract: One embodiment of the present method and apparatus encompasses an apparatus that may have: a predetermined length, the self-imaging semiconductor waveguide having first and second opposed sides; quantum wells disposed within the self-imaging semiconductor waveguide along the length of the self-imaging semiconductor waveguide, the quantum wells being formed of a quantum well gain material; microchannel cooler that extends substantially the width of the self-imaging semiconductor waveguide, the microchannel cooler located adjacent the first side of the self-imaging semiconductor waveguide; and a plurality of pump arrays arranged along the microchannel cooler opposed from the first side of the self-imaging semiconductor waveguide; wherein the quantum well gain material is photopumped through the microchannel cooler.

Abstract: A Reflective Semiconductor Optical Amplifier (RSOA) for compensating for light loss in an optical link, an RSOA module for improving polarization dependency using the RSOA, and a Passive Optical Network (PON) for increasing economical efficiency and practical use of a bandwidth using the RSOA are provided. The PON includes a central office comprising a plurality of optic sources transmitting a downstream signal and a plurality of first receivers receiving an upstream signal; at least one optical network terminal (ONT) including a second receiver receiving the downstream signal and an RSOA which receives the downstream signal, remodulates the downstream signal into the upstream signal, and transmits the upstream signal in loopback mode; and a remote node interfacing the central office with the ONT. The upstream signal and the downstream signal are transmitted between the remote node and the ONT via a single optical fiber. The remote node includes an optical power splitter at its port connected to the ONT.

Abstract: A method of optical communication includes generating an amplified optical signal from at least a portion of a first optical signal having a first carrier wavelength, ?1. The amplified optical signal is applied to Brillouin media to stimulate generation of a Brillouin effect signal at a wavelength ?2. The Brillouin effect signal is modulated to produce a second optical signal having a second carrier wavelength, ?2. In one embodiment, the first optical signal is a downstream optical signal and the second optical signal is an upstream optical signal of a passive optical network.

Abstract: Methods and devices of the invention perform an optical concentration by an expansion of usable spectral width of the incident energy. Preferred methods and devices of the invention concentrate optical energy by tuning it into a narrow spectral width to match the bandgap of another system component, such as an optical fiber, an optical sensor or a photovoltaic device that converts the optical energy. Embodiments of the invention include methods and devices for the spectral concentration of multi-wavelength light and subsequent transport of the concentrated output light.

Abstract: Nanowire-based opto-electronic devices including nanowire lasers, photodetectors and semiconductor optical amplifiers are disclosed. The devices include nanowires grown from single crystal and/or non-single surfaces. The semiconductor optical amplifiers include nanowire arrays that act as ballast lasers to amplify a signal carried by a signal waveguide. Embodiments of the nanowire lasers and photodetectors include horizontal and vertical nanowires that can provide different polarizations.

Abstract: A wavelength conversion system includes a Mach-Zehnder interferometer including two optical waveguides, a non-linear medium provided on one of the two optical waveguides, and a branching ratio adjuster for adjusting the branching ratio of multiplexed light produced by multiplexing signal light and pumping light so that the powers of the signal light and the pumping light which are to be emitted from the two optical waveguides are equal to each other. The multiplexed light whose branching ratio is adjusted by the branching ratio adjuster is introduced into the two optical waveguides such that the non-linear medium generates phase conjugation light of the signal light and the light guided through the one optical waveguide and the light guided through the other one of the two optical waveguides interfere with each other so that the phase conjugation light is extracted as wavelength conversion light.

Abstract: The invention provides a device and a method for extending the bandwidth of short wavelength and long wavelength fiber optic lengths. The invention provides for an optical transmitter package device comprising: a laser diode; and a semiconductor optical amplifier connected directly after and in close proximity to the laser diode, wherein the semiconductor optical amplifier is adapted to operate in a frequency domain such that the semiconductor optical amplifier filters and reshapes optical wavelengths from the laser diode, and wherein the semiconductor optical amplifier is biased below an amplification threshold for the semiconductor optical amplifier. The device may also comprises a feedback circuit which comprises an optical splitter, wherein the feedback circuit samples reshaped optical output from the semiconductor optical amplifier and dynamically adjusts one or both of the semiconductor optical amplifier and the laser diode.

Abstract: An integrated optical device includes a plurality of semiconductor lasers which emit different wavelengths of laser light, a comparator circuit which compares voltages across terminals of the respective plurality of semiconductor lasers, and outputs a signal depending on the comparison result, a light-receiving element which outputs a photocurrent depending on the amounts of laser light emitted from the plurality of semiconductor lasers, and a current mirror circuit which switches between amplification and attenuation with respect to the photocurrent output from the light-receiving element based on the signal output from the comparator circuit, and outputs a monitor signal.

Abstract: A method of estimating an injection power of seed light injected into an injection-seeded transmitter. A back face monitoring (BFM) response of the injection-seeded transmitter is determined, and data representative of the BFM response stored in a memory. During run-time, a controller of the injection-seeded transmitter, detects a temperature of the injection-seeded transmitter and an instantaneous BFM current. BFM response data is obtained from the memory based on the detected temperature, and the seed light injection power estimated based on the obtained data and the detected instantaneous BFM current.

Abstract: The present invention is an optical semiconductor device including a lower clad layer 12 having a first conduction type, an active layer 14 that is provided on the lower clad layer 12 and has multiple quantum dot layers 51-55 having multiple quantum dots 41, and an upper clad layer 18 that is provided on the active layer 14 and has a second conduction type opposite to the first conduction type, the multiple quantum dot layers 51-55 having different quantum dot densities.

Abstract: An edge photo-pumped semiconductor slab amplifier including an undoped semiconductor slab. A first gain structure is formed on an upper surface of the slab and a second gain structure is formed on a lower surface of the slab. The gain structures can be resonant periodic gain structures including a plurality of stacked quantum well layers. Confining layers are coupled to the gain structures to confine a signal beam within the semiconductor slab. Heat sinks are thermally coupled to the confining layers. Optical pump sources are provided along the side edges or coupled to the end edges of the slab so that pump light is introduced into the slab through the edges to provide gain for the quantum well layers.

Abstract: To accommodate a plurality of optical semiconductor elements in one package with their optical axes aligned highly precisely. An optical transmission module includes an optical transmission unit, a carrier to become a base, a semiconductor optical amplification element mounted on the carrier through a first sub-carrier, first and second lenses fixed on the carrier through first and second lens holders, an element supporting member and an optical isolator fixed on the carrier, a third lens holder supported by the element supporting member, a third lens and a small carrier individually fixed in the third lens holder, and a semiconductor laser element mounted on the small carrier through a second sub-carrier.

Abstract: An optical amplification control apparatus is formed from a semiconductor optical amplifier, a temperature adjustment unit adjusting the temperature of the semiconductor optical amplifier, and an optical gain control unit adjusting the temperature of the semiconductor optical amplifier by controlling the temperature adjustment unit, and varying an optical gain of the semiconductor optical amplifier. Thus, a pattern effect is suppressed even if the output light intensity (the intensity of amplified light) is increased.

Abstract: An optical circuit is described which may include an SOA-MZI circuit providing an output signal; and a polarization filtering device (PFD) configured to receive the output signal of the SOA-MZI and to provide at least one signal at the output of the PFD.

Abstract: The present invention is a laser system including a DFB laser 10 emitting a laser light 50, a semiconductor optical amplifier 20 that modulates an intensity of the laser light, and a harmonic generation element 30 that converts the laser light modulated to a visible light 54 that is a harmonic of the laser light. According to the present invention, it is possible to employ the highly efficient harmonic generation element capable of modulating the intensity of the laser light and to reduce power consumption.

Abstract: A modulator includes an electro-optical substrate and a first and second waveguide formed of a doped semiconductor material positioned on a surface of an electro-optical substrate forming a slot therebetween. A doping level of the semiconductor material being chosen to make the first and second waveguide conductive. A dielectric material is positioned in the slot which increases confinement of both an optical field and an electrical field inside the slot. A refractive index of the semiconductor material and a refractive index of the dielectric material positioned in the slot being chosen to reduce the V?·L product of the modulator.

Abstract: Invention relates to three types of laser light sources: diode laser, integral diode laser (in form of integrally connected diode lasers) and integral semiconductor optical amplifier (in form of integrally connected driving laser diode and semiconductor amplifier element), which amplifier consists of original optical resonator of diode laser and original laser radiation coupling. Two reflectors in optical resonator of diode laser, which falls into three types of above-mentioned laser radiation sources, have greatest possible reflection factor on both sides thereof and radiation coupling from active layer is carried out, by-passing active layer, through broadband semiconductor layers of the modified heterostructure of diode laser with practically fully antireflective (less than 0.01%) optical face.

Abstract: Provided are a photomixer module and a method of generating a terahertz wave. The photomixer module includes a semiconductor optical amplifier amplifying incident laser light and a photomixer that is excited by the amplified laser light to generate a continuous terahertz wave. The photomixer is formed as a single module together with the semiconductor optical amplifier.

Abstract: A system to control an optical signal may include a semiconductor laser diode. The system may also include an optical amplifier to receive an optical signal from the semiconductor laser diode. The optical amplifier may be configured to spectrally filter the optical signal.

Abstract: A light source apparatus includes an optical resonator provided with a plurality of gain media that amplify light and an optical waveguide and a control unit configured to individually control amplification factors of the plurality of gain media, in which the plurality of gain media have mutually different maximum gain wavelengths whose amplification regions are mutually partially overlapped, and a wavelength at which a total gain by the plurality of gain media becomes a maximum value is set to be variable on the basis of the control on the amplification factors.

Abstract: Provided is an optical device module that can improve miniaturization and integration. The optical device module includes a semiconductor optical amplifier having a buried structure and including a first active layer buried in a clad layer disposed on a first substrate, an optical modulator in which a sidewall of a second active layer disposed in a direction of the first active layer on a second substrate junctioned to the first substrate is exposed, the optical modulator having a ridge structure, and at least one multi-mode interference coupler in which the second active layer junctioned to the first active layer is buried in the clad layer, the multi-mode interference coupler sharing the second active layer on the second substrate between the optical modulator and the semiconductor optical amplifier and integrated with the second optical device.

Abstract: An electrically pumped lateral emission electroluminescent device may include a slotted waveguide including a top silicon layer having a thickness between 150 nm and 300 nm and a refraction index associated therewith, and a bottom silicon layer having a thickness between 150 nm and 300 nm and a refraction index associated therewith. A core layer may include silicon oxide between the top and bottom layers and a thickness less than 70 nm. A core layer refraction index may be greater than each of the top and bottom layer refraction indices. A core layer portion may be in a direction of light propagation and may be doped with erbium, and may include silicon nanocrystals. A portion of each of the top and bottom layers may coincide with the core layer portion and may be doped so that the top and bottom layer portions are electrically conductive to define top and bottom plates.

Abstract: An optical amplifier includes a semiconductor optical amplifier, a power monitor configured to monitor an optical power of out-of-signal-band noise output from the semiconductor optical amplifier, and a corrector configured to correct a relationship between a driving current for the semiconductor optical amplifier and a noise optical power based on the out-of-signal-band noise optical power monitored by the first power monitor.

Abstract: This invention provides a method for upgrading the network rate of a Passive Optical Network (PON), which mainly includes: upgrading the optical fiber line rate of the central office device, and adapting, by the network terminal device, the working rate of the upstream/downstream line automatically to the optical fiber line rate of the central office device according to a downstream data flow transmitted from the central office device. Using the method of this invention, the network rate of the PON can be upgraded without replacing the network terminal and without a manual intervention.

Abstract: The present invention provides an optical device capable of suppressing a drive current and an optical output to be varied with a passage of the time. The optical device includes: an optical element including a first end face and a second end face, and emitting light having a wavelength from 300 nm to 600 nm both inclusive at least from the second end face in the first end face and the second end face; a pedestal including a supporting substrate supporting the optical element, and a connecting terminal electrically connected to the optical element; and a sealing section including a light transmitting window in each of a portion facing the first end face and a portion facing the second end face, and sealing the optical element.

Abstract: A semiconductor optical amplifier (SOA) with efficient current injection is described. Injection current density is controlled to be higher in some areas and lower in others to provide, e.g., improved saturation power and/or noise figure. Controlled injection current can be accomplished by varying the resistivity of the current injection electrode. This, in turn, can be accomplished by patterning openings in the dielectric layer above the current injection metallization in a manner which varies the series resistance along the length of the device.

Abstract: Provided are a reflective semiconductor optical amplifier (R-SOA) and a superluminescent diode (SLD). The R-SOA includes: a substrate; an optical waveguide including a lower clad layer, an active layer independent of the polarization of light, and an upper clad layer sequentially stacked on the substrate, the optical waveguide comprising linear, curved, and tapered waveguide areas; and a current blocking layer formed around the optical waveguide to block a flow of current out of the active layer, wherein the linear and curved waveguide areas have a single buried hetero (BH) structure, and the tapered waveguide area has a dual BH structure.

Abstract: In one embodiment of the invention, a semiconductor optical amplifier (SOA) in a laser ring is chosen to provide low polarization-dependent gain (PDG) and a booster semiconductor optical amplifier, outside of the ring, is chosen to provide high polarization-dependent gain. The use of a semiconductor optical amplifier with low polarization-dependent gain nearly eliminates variations in the polarization state of the light at the output of the laser, but does not eliminate the intra-sweep variations in the polarization state at the output of the laser, which can degrade the performance of the SS-OCT system.

Abstract: An optical circuit is disclosed, which may include a semiconductor optical amplifier (SOA); an optical filter operable to filter light emerging from the SOA; and a PIN for converting the light output from the optical filter into an electrical signal, wherein the gain profile of the optical filter is configured to maximize throughout of signal energy within a predetermined wavelength range (in-band), and to impose an insertion loss (Loob) of less than 20 dB on signal energy outside the predetermined wavelength range.