Abstract: A delivery fiber assembly suitable for delivering broad band light and including a delivery fiber and a connector member. The delivery fiber has a length, an input end for launching light, and a delivery end. The delivery fiber includes along its length a core region and a cladding region surrounding the core region, the cladding region includes a cladding background material having a refractive index Nbg and a plurality of microstructures in the form of inclusions of solid material having refractive index up to Ninc and extending in the length of the longitudinal axis of the delivery fiber, wherein Ninc<Nbg. The plurality of inclusions in the cladding region is arranged in a cross-sectional pattern including at least two rings of inclusions surrounding the core region. The connector member is mounted to the delivery fiber at a delivery end section of the delivery fiber including the delivery end.

Abstract: A laser system may include one or more seed lasers to generate a pulsed seed beam including one or more laser pulses, a pulse pattern generator to generate an intermediate patterned burst-mode beam from at least one laser pulse from the pulsed seed beam, where the pulse pattern generator includes splits the at least one laser pulse from the pulsed seed beam along two or more delay paths and combines light along the two or more delay paths to a common optical path, and where the intermediate patterned burst-mode beam includes laser pulses with a selected pattern of inter-pulse spacings associated with the two or more delay paths. The laser system may further include power amplifiers to amplify the intermediate patterned burst-mode beam to form an amplified patterned burst-mode beam, where the amplified patterned burst-mode beam includes amplified laser pulses with the selected pattern of inter-pulse spacings.

Abstract: The invention comprises a delivery fiber assembly suitable for delivering broad band light. The delivery fiber assembly comprises a delivery fiber and a connector member. The deliver has a length, an input end for launching light and a delivery end for delivering light, where the delivery fiber comprises along its length a core region and a cladding region surrounding the core region. The cladding region comprises a cladding background material having a refractive index Nbg and a plurality of inclusions of solid material having refractive index up to Ninc and extending in the length of the longitudinal axis of the delivery fiber, wherein Ninc<Nbg and the plurality of inclusions in the cladding region is arranged in a cross-sectional pattern comprising at least two rings of inclusions surrounding the core region. The connector is mounted to the delivery fiber at a delivery end section of the delivery fiber comprising said delivery end.

Abstract: The invention comprises a delivery fiber assembly suitable for delivering broad band light and comprising a delivery fiber and a connector member. The delivery fiber has a length, an input end for launching light and a delivery end for delivering light. The delivery fiber comprises along its length a core region and a cladding region surrounding the core region wherein the cladding region comprises a cladding background material having a refractive index Nbg and a plurality of microstructures in the form of inclusions of solid material having refractive index up to Ninc and extending in the length of the longitudinal axis of the delivery fiber, wherein Ninc<Nbg. The plurality of inclusions in the cladding region is arranged in a cross-sectional pattern comprising at least two rings of inclusions surrounding the core region. The connector member is mounted to the delivery fiber at a delivery end section of the delivery fiber comprising the delivery end.

Abstract: Methods and systems enable amplifying optical signals using a Bragg reflection waveguide (BRW) having second order optical nonlinearity to generate an optical pump by injection locking. The BRW may also be used for parametric amplification of optical signals using the optical pump. Feedback phase-power control may be performed to maximize output power.

Abstract: Methods and systems enable amplifying optical signals using a Bragg reflection waveguide (BRW) having second order optical nonlinearity to generate an optical pump by injection locking. The BRW may also be used for parametric amplification of optical signals using the optical pump. Feedback phase-power control may be performed to maximize output power.

Abstract: An optical device, comprising an optical component, configured to produce optical amplification; a component configured to intermittently supply coherent light to said optical component; and a controller, configured to apply a time varying signal to said optical component such that a plurality of light pulses are emitted during each period of time that said coherent light is received, wherein the plurality of light pulses emitted during each period have a fixed phase relation.

Abstract: A method of controlling beam quality and stability of a laser apparatus, the laser apparatus comprising, a diode laser (10) providing first radiation of at least a first wavelength, and a frequency conversion unit (12) configured to frequency-convert the first radiation from the diode laser and to output the frequency-converted radiation (213), the frequency-converted radiation having at least a second wavelength different from the first wavelength, the diode laser (10) comprising at least a first and a second section (222,223), a first contact (220) for injecting a first current (I1) into the first section (222), a second contact (221) for injecting a second current (I2) into the second section (223), and means for controlling a temperature of the diode laser; wherein the method comprises monitoring a first parameter indicative of the power content of a dominant lobe of the first radiation; iteratively determining a combination of respective values of the first current, the second current and the temperature

Abstract: A coherent optical receiver includes a local oscillator (LO) laser configured to provide an LO signal. The LO laser includes a hybrid external cavity and an active gain medium within the hybrid external cavity, where the LO laser is defined between a first optical reflector on a chip including the active gain medium and a second optical reflector not on the chip.

Abstract: A pulse fiber laser device 1 has a Fabry-Perot type optical resonator, and is provided with an excitation light source 11, an optical coupling unit 12, an amplifying optical fiber 13, a saturable absorber 14, a gradient index lens 15, an optical output unit 16, a dispersion adjusting unit 17, a mirror 21 and a mirror 22. The saturable absorber 14 and the mirror 21, integrated into one body, constitute a saturable absorber mirror 23. The gradient index lens 15 converges the light output from an end face of an optical fiber 32 and outputs the light to the saturable absorber mirror 23, and inputs the light reflected from the saturable absorber mirror 23 into the end face of the optical fiber 32. Thus, there is provided a pulse fiber laser device that enables easy adjustment of the intensity of light incident on a saturable absorber and facilitates miniaturization.

Abstract: The pulse light source according to the present invention comprises: a seed pulse generator 1 for outputting an input pulse 10 as a seed pulse; a pulse amplifier 2; and a dispersion compensator 3 for dispersion compensating a light pulse output from the pulse amplifier 2. Moreover, the pulse amplifier 2 comprises a normal dispersion medium (DCF 4) and an amplification medium (EDF 5) that are multistage-connected alternately, for changing the input pulse 10 to a light pulse having a linear chirp and outputting the light pulse. Furthermore, an absolute value of the dispersion of the DCF 4 becomes to be larger than the absolute value of the dispersion of the EDF 5.

Abstract: A device for amplifying high-energy ultrashort light pulses, includes a generator (1), a first amplifying/time-stretching element (2) including a time-stretching element (3), a regenerative amplifier (4), a multipass amplifier (5) and a compressor (6). The device further includes a second amplifying/time-stretching element (11), arranged at the output of the generator (1), amplifying and time-stretching the initial light pulses (7) to generate amplified and time-stretched pulses (13), and a filtering element (12) arranged between the second amplifying/time-stretching element (11) and the amplification unit (2), blocking the low-amplitude light signals (14) of the amplified and time-stretched pulses (13).

Abstract: A tilt correction pump laser is injected into an optical fiber in an opposite direction of the transmission direction of a wavelength multiplex signal and an optical isolator or filter is provided to block the tilt correction signal in order to restrict the effective fiber length for the tilt correction pump signal to enable a faster adjustment of the tilt.

Abstract: In an optical parametric amplifier of the invention, pumping light which is amplified using a practical optical amplifier such as an EDFA is supplied together with signal light having a wavelength outside the amplification band of the optical amplifier, to a nonlinear optical medium via a multiplexer, to thereby amplify the signal light by an optical parametric amplification effect due to the pumping light in the nonlinear optical medium. As a result, the amplification band of a practical optical amplifier such as an EDFA, can be extended, and the noise characteristics can be improved.

Abstract: An optical-signal processing apparatus includes a polarizer that is provided at an output terminal of an optical fiber, and polarization control units that adjust a first excitation light and a second excitation light input to the optical fiber. The polarization control units adjust polarization states of the first excitation light and the second excitation light so that, when the first excitation light and the second excitation light are input to the polarizer, polarization directions of the first excitation light and the second excitation light are orthogonal to each other, and angular difference between the polarization direction of the first excitation light and the polarization direction of the second excitation light, measured against the polarization main axis of the polarizer, is equal to or smaller than a threshold value.

Abstract: The invention relates to optical fibers for use in optical amplification of light, such as in optical fiber amplifiers and lasers and for use in delivery of high power light, in particular to a scheme for reducing amplified spontaneous emission at undesired wavelengths. The invention further relates to articles, methods and use. An object of the invention is achieved by a micro-structured optical fiber, which is adapted to guide light by the photonic bandgap effect and to have one or more pass bands and at least one stop-band over a wavelength range from ?stop1 to ?stop2. In an aspect of the invention, the at least one stop-band provides filter functions that suppress nonlinear effects.

Abstract: A chirped pulse amplification (CPA) system comprises an optical pulse stretcher and an optical pulse compressor that are mismatched in that the optical pulse compressor includes a bulk optical grating while the optical pulse stretcher does not. High order dispersion compensation is provided by an optical phase mask disposed within the optical pulse compressor.

Abstract: Data of a barometric pressure that a barometric pressure sensor outputs, and data of an air volume that an air-volume sensor outputs are input into a system control circuit. The system control circuit is provided with a table storing portion. In the table storing portion, a control table is stored. The control table is formed of a plus supplied-voltage value to fan power set by a barometric pressure value and an air-volume value, and a warning instruction. In a case that the warning instruction is selected based on the barometric pressure value and the air-volume value, the system control circuit turns on a warning-use LED so as to inform a user that a filter is clogged.

Abstract: An optical arrangement and method of filtering include a beam splitter that accepts an incident beam and transmits light from the incident beam of a first polarization and reflects light from the incident beam of a second polarization. The transmitted light is a first beam and the reflected light is a second beam. A first spectral filter, receives the first beam, reflects a first spectral band of the first beam, and transmits the remainder of the first beam. A second spectral filter receives the remainder of the first beam and reflects a second spectral band of the first beam. The first and second spectral filters can also receive the second beam and reflect similar first and second spectral bands. The spectral bands are then returned to the beam splitter, where they may be directed toward a dispersal element or an array of photodetectors.

Abstract: Disclosed is a high speed optical signal processor which includes a saturable absorber area including a substrate, an active layer, a clad layer and a first upper electrode which are sequentially formed on one face of the substrate, and a first lower electrode formed on the other face of the substrate; and a gain-clamped optical amplifier area including a substrate having a diffraction grating for generating a laser beam, an active layer, a clad layer and a second upper electrode which are sequentially formed on one face of the substrate, and a second lower electrode formed on the other face of the substrate, the second upper electrode being isolated from the first upper electrode of the saturable absorber area.

Abstract: The present invention relates to all-optical OR and XOR logic elements employing saturable absorbers as optical gates. Saturable absorbers are arranged in paths of the Mach-Zehnder interferometer, respectively. If the total power of an input optical signal and a continuous wave signal is higher than a transparent input power of the saturable absorbers, the input optical signal passes through the saturable absorbers, and then the optical signals through the two paths are combined, so that it is possible to obtain the operational characteristics of the OR and XOR logic elements. According to the present invention, unlike the optical logic element using a cross-phase modulation by a semiconductor optical amplifier, phase difference depending upon the input optical power is not generated between two paths, so that it is possible to alleviate a restriction of an allowable range of the input optical power.

Abstract: An optical dispersion compensator includes a saturable absorber. Coupled to the saturable absorber is a pre-amplifier and a post-amplifier. The saturable absorber compresses optical pulse signals based upon the amplitude envelope of the optical pulse in order to prevent optical dispersion.

Abstract: An optical transmission system having an optical regeneration circuit for regenerating a signal with a deteriorated signal to noise ratio. A signal light at wavelength &lgr;1 which includes a noise light is composed with a continuous light at wavelength &lgr;2 outputted from a light source to obtain a composed signal light in an optical coupler. The composed signal light is passed through a saturable absorption type optical element which transmits only the signal light having a light intensity equal to or greater than a threshold value, thereby removing the included noise light. From the signal light, only the signal at the same wavelength &lgr;2 as the wavelength of the continuous light is extracted by a wavelength divider and data signal of the incident signal light is replicated in the continuous light and outputted. Thus, a signal light having no deterioration of the signal to noise ratio at wavelength &lgr;2 can be regenerated from the signal light having the deteriorated signal to noise ratio.

Abstract: A partial optical regenerator for use in high bit-rate optical systems and useful in WDM applications employing soliton transmission. The regenerator essentially comprises a saturable optical element in a main optical path and a resonant optical circuit coupled to the element. A resonant pulse can be generated from an input data pulse in a number of ways. (A) an input data pulse may be coupled directly to the resonant optical circuit before entering the element; (B) the input data pulse may first saturate the element, resulting in the creation of a counter-propagating pulse; (C) the data pulse may pass through the element and be coupled to the resonant optical circuit upon exit. The resonant pulse travels around the resonant circuit and repeatedly returns to the saturable optical element after an integer multiple of the symbol duration or after an odd integer multiple of half the symbol duration.

Abstract: An optical functional amplifying device suitable for use in an optical gate which operates at a very high repetition frequency such as a frequency exceeding 100 GHz. The device has a semiconductor laser amplifier having a gain section and a saturable absorber section, a first optical coupler for coupling an input signal optical pulse train having a wavelength whose value is set near the absorption edge of the saturable absorber section in the semiconductor laser amplifier, a second optical coupler for coupling a gate optical pulse train having a wavelength shorter than that of the input signal optical pulse train to the semiconductor laser amplifier, and a selector for separating and extracting a signal optical pulse train emitted from the semiconductor laser amplifier from the gate optical pulse train.

Abstract: An optical wavelength-division multiplexing transmission system includes an optical wavelength-division multiplexing transmitter, an optical wavelength-division multiplexing receiver, and a plurality of optical amplifiers disposed on an optical transmission line connecting the transmitter and receiver. Optical filters are disposed on said optical transmission line for flattening the pass band gain characteristics of a predetermined number of optical amplifiers. It is desirable that one optical filter is disposed for every one to thirty amplifiers. The optical wavelength-division multiplexing transmission system of the present invention can thus flatten accumulated gain characteristics of the amplifiers so that several different wavelengths can be transmitted without attenuation.

Abstract: An optical light source signal generator comprising an optical amplification medium for generating amplified spontaneous emission (ASE), having forward and backward light propagating ports for outputting output and backward optical light respectively, a reflector for reflecting the backward propagating optical light back toward the backward light propagating port, and an optical light spectrum reshaper interposed between the reflector and the backward light propagating port for transmitting the reflected light to the backward light propagating port with a wavelength dependence having a reduced amplitude in a band coinciding with an undesired high gain band of the optical amplification medium.

Abstract: An optical repeater is described which integrates an erbium doped optical fiber amplifier (EDFA) with a dispersion equalizer (DE) based on fiber gratings. The dispersion equalizer is based on parallel connection of two fiber gratings for single carrier wavelength operation, and on parallel connection of a cascade of two fibre grating branches, each carrying a plurality grating elements chirped for different wavelengths, for WDM operation at a plurality of wavelengths.The use of two gratings sections for each wavelength improves the optical bandwidth of the equalizer compared with single grating designs, doubling the effective bandwidth. Further, the grating DE is disposed between two fiber amplifier sections which share a single pump laser. Thus, this arrangement provides dispersion compensation and loss compensation in an optical repeater of lower cost, and smaller size, compared to a system of similar performance configured using discrete components.

Abstract: To enable the surveillance of a long-distance optical fiber line that a method using the reflection lights and Rayleigh backscatter lights cannot cover, a plurality of optical reflection elements P1-Pn are interposed in the optical fiber line at each specific distance. Each of the optical reflection elements P1-Pn reflects only a light signal of one of specific wavelengths .lambda.1-.lambda.n on a constant level. Light pulses of the specific wavelengths .lambda.1-.lambda.n are transmitted to the optical fiber line to measure intensities of the light pulses reflected by the optical reflection elements P1-Pn. From the measurement, surveillance of the optical fiber line can be done between the transmitter and each of positions of the optical reflection elements P1-Pn. The reflectance of the optical reflection elements P1-Pn can be set to 100%, and the surveillance becomes possible even if the length of the optical fiber line exceeds 200 km.

Abstract: An optical fiber amplifier includes an optical filter, an optical isolator for blocking a reverse flow of a reflected light, the optical isolator including a lens coated with an integral filter having a predetermined bandwidth and an output end tab for monitoring the intensity of the output signal, the optical filter being coupled between the optical isolator and output end tab so as to only pass a specified wavelength band.

Abstract: Limiting quadratic processing and compansion in photorefractive two beam coupling is disclosed. Two-beam coupling in photorefractive barium titanate employs the imaged intensity of the signal to amplify the reference beam while maintaining the phase of the reference beam. The phase distorted signal beam is converted to that of the controlled phase of the reference beam. The high pump limit of amplification in this two-beam coupling device produces an amplitude compressed output to reduce multiplicative noise. Lost contrast of the image is thereafter restored. Beam clean-up of a non-intelligence bearing beam can be carried out by a similar process; a low pass filter consisting of a pinhole plate can be used in place of the second photorefractive crystal in the Fourier plane and only the planar wavefront portion will pass through the pinhole and may be collimated by a lens to provide a cleaned planar output beam.

Abstract: An optical interference filter produced on a vitreous, light transmissive substrate, such as an electric lamp envelope, includes a plurality of alternating layers of tantala and silica in which each tantala layer includes titania in an amount of less than about 10 mole % whereby the microstructure of the tantala layers is controlled during subsequent crystallization and extrinsic stress in the tantala layers is reduced. Rather than or in addition to including titania in each tantala layer, the present invention additionally contemplates placing at least some of the tantala layers in contact with a titania layer (pre-layer and/or post-layer) whereby the microstructure of the tantala layers is controlled during subsequent crystallization and extrinsic stress in the tantala layers is reduced.

Abstract: A technique for reducing signal degradation and fading within a long optical transmission system by minimizing polarization dependent hole-burning ("PDHB") through the cyclic stressing of a birefringent optical fiber to modulate the SOP of an optical signal launched into the transmission system. This effectively reduces the degree of polarization of the launched optical signal, without degrading the noise and dispersion characteristics of the signal. The modulation frequency of the SOP is chosen to ensure that the launched signal does not remain at a particular SOP long enough to anisotropically saturate any optical amplifier employed within the transmission system, and give rise to PDHB.

Abstract: A technique for reducing signal degradation and fading within a long optical transmission by utilizing a rotating waveplate arrangement to rotate the SOP of an optical signal launched into the transmission system, and thereby minimize polarization dependent hole-burning ("PDHB"). This effectively reduces the degree of polarization of the launched optical signal, without degrading the noise and dispersion characteristics of the signal. The rate of waveplate rotation is chosen to ensure that the SOP of the launched signal does not remain at a particular SOP long enough to anisotropically saturate any optical amplifier employed within the transmission system, and give rise to PDHB.

Abstract: An arrangement for operation as an optical feedback amplifier which is composed of a DFB laser whose grating selects a wavelength that differs by so much from the wavelength at which the amplification medium has a maximum gain that a constant amplification effect at this beamed-in wavelength is achieved by a progressive quenching of the emission of this wavelength selected by the grating given external optical irradiation via a coupled waveguide of light having a wavelength in the proximity of the wavelength of the gain maximum of the amplification medium.

Abstract: An optical limiting amplifier is disclosed having a high gain over a wide dynamic range of input power levels. The amplifier has an input stage (102) and an output stage (103), each of which includes an erbium-doped fiber amplifier (104, 106). The erbium-doped fiber amplifier in the input stage provides a high gain in order to saturate the amplifier in the second stage. The erbium-doped fiber amplifier in the output stage is fabricated with a small core diameter to saturate at reasonably small signal levels, and has a relatively lower total number of erbium ions in order to limit amplification once deep saturation is reached.

Abstract: A monolithic integrated master oscillator power amplifier is provided comprising means for generating and emitting a laser beam and means for amplifying the laser beam. The amplifying means is in communication with the generating and emitting means, and the amplifying means has a region in which the laser beam can expand freely prior to being outputted from the amplifying means. The means for generating and emitting and the amplifying means are coupled to each other by means for selectively controlling the laser beam as the laser beam is communicated from the generating and emitting means to the amplifying means. The means for generating and emitting and the controlling means are in communication with means for supplying pumping current independently to each of the generating and emitting means and the controlling means.

Abstract: An optical fiber amplifier in which light generated within an Er doped optical fiber by spontaneous emission is eliminated or suppressed. By inserting a wavelength demultiplexer in the Er doped optical fiber, the light generated within the optical fiber by spontaneous emission can be effectively eliminated. As an alternative, the Er doped optical fiber is arranged in a coil form with a predetermined radius of curvature to thereby effectively eliminate light due to spontaneous emission on the longer wavelength side than the signal light. Further, by doping the center portion of the core of an optical fiber with aluminum and the whole body of the core uniformly with erbium, it is made possible to suppress the generation of light by spontaneous emission without causing an adverse effect on the amplification performance of the signal light.

Abstract: An all-optical, continuous-time, recurrent neural network is disclosed which is capable of executing a broad class of energy-minimizing neural net algorithms. The network is a resonator which contains a saturable, two-beam amplifier; two volume holograms; and a linear, two-beam amplifier. The saturable amplifier permits, through the use of a spatially patterned signal beam, the realization of a two-dimensional optical neuron array; the two volume holograms provide adaptive, global network interconnectivity; and the linear amplifier supplies sufficient resonator gain to permit convergent operation of the network.