Abstract: A system for generating a series of reducing intensity laser pulses from an ultrafast pulsed laser source. The reducing intensity series of pulses is equally temporally spaced between pulses from the laser source. The repeating series of reducing intensity laser pulses is fed to a microscope for imaging. The microscope is capable of detecting the fluorescence from a sample generated by each pulse in the series. The data is processed using knowledge of the pulse intensity, location on the test sample, and amount of fluorescence measured to create an increased dynamic range of the image relative to what can be obtained in a normal two-photon imaging system.

Abstract: A method for obtaining one or more images of a sample using a microscope includes dividing, using a reverberation cavity, a first one of a plurality of laser pulses into a plurality of sequential sub-pulses, each of the plurality of sequential sub-pulses having a power that is less than a previous one of the plurality of sequential sub-pulses, directing, using the one or more lenses of the microscope, the plurality of sequential sub-pulses onto a portion of the sample to generate a plurality of signals, each of the plurality of signals being associated with a different depth within the sample, and detecting the plurality of signals from the sample to generate one or more images of at least a portion of the sample.

Abstract: High power, high speed VCSEL arrays are employed in unique configurations of arrays and sub-arrays. Placement of a VCSEL array behind a lens allows spatial separation and directivity. Diffusion may be employed to increase alignment tolerance. Intensity modulation may be performed by operating groups of VCSEL emitters at maximum bias. Optical communications networks with high bandwidth may employ angular, spatial, and/or wavelength multiplexing. A variety of network topologies and bandwidths suitable for the data center may be implemented. Eye safe networks may employ VCSEL emitters may be paired with optical elements to reduce optical power density to eye safe levels.

Abstract: An optical time delay control device for controllably altering the transit time of an optical beam between two points. In one example, the device may include an optically transparent solid medium for receiving the optical beam, wherein at least a portion of the medium is generally a parallel piped shape characterized by a height, length and width, wherein the length is larger than the height; two mirrors affixed to two opposing parallel surfaces of the optically transparent solid medium, so that during operation the optical beam reflects between the two mirrors as the optical beam travels through the optically transparent medium; and an angle actuator for controllably altering the angle at which the optical beam enters into the optically transparent medium, thereby controllably altering the time that the optical beam travels through the device. This in effect permits control of the amount of delay of the transmission of light, and delays of 20 nanoseconds have been achieved.

Abstract: An Integrated Laser Field Conjugation System (ILFCS) for end-to-end compensation of high-energy laser for propagation through turbulence with non-cooperative target. ILFCS using interferometric slaving technique and stand-alone adaptive optical systems to effect pre-compensation of amplitude and phase aberrations in turbulent medium, providing pre-compensation for aberrations in a laser amplifier. Performing compensation functions in low-power beam paths, increasing capability, reducing cost, reducing size compensation components for phase correction devices. Pre-compensating low-power master oscillator beam for aberrations in both high-power amplifier and turbulent propagation path-to-target with configuration enabling wavefront sensing of aberrations. Can be configured to perform phase compensation, or compensation of phase/amplitude aberrations. Capability to compensate aberrations in master oscillator beam.

Abstract: A solid state light source comprising a light pump outputting light energy; a waveguide optically coupled to the light pump source for receiving the light energy; and a down-converter for converting the light energy from the waveguide to a lesser light energy.

Abstract: A pulse modifier, and associated lithographic apparatus and a method for manufacturing a device, is disclosed. The pulse modifier is configured to receive an input pulse of radiation and further configured to emit a plurality of corresponding output pulse portions of radiation, wherein the respective pulse portions are respectively mirrored about an axis transverse to the optical axis and mirrored about a point of the optical axis of the pulse portions.

Abstract: The invention relates to a highly repetitive laser system operating according to the reproducible amplifier principle. Said system comprises at least one amplified laser medium, a laser resonator provided with at least one resonator mirror and at least one modulator and a pump source, in particular, a laser diode source, which is used to pump the laser medium. The highly repetitive laser system is compact by virtue of the fact that a pulse extensor, having a highly dispersive effect as a result of the structure or material thereof, is integrated into the laser resonator.

Abstract: The apparatus for extending or lengthening a laser pulse has a beam splitter. An incident laser pulse is split by the beam splitter into at least one first partial pulse and a second partial pulse. The first partial pulse is conducted through a delaying travel path section with a number of reflectors. The apparatus is characterized by a plurality of the variable delaying travel path sections which produce different length laser beam pulses from a single incident laser pulse.

Abstract: Laser apparatus is disclosed in which fundamental-wavelength optical pulses delivered from a mode-locked laser resonator at a pulse-repetition frequency (PRF) are converted to harmonic-wavelength pulses in an optical delay loop. One example is disclosed in which the harmonic-wavelength pulses are delivered directly from the delay loop. Another example is disclosed in which the harmonic-wavelength pulses are divided by the delay loop into a number of temporally spaced-apart replicas thereof, and the delay loop delivers bursts of replicas of different one of the harmonic wavelength pulses at a burst-repetition frequency equal to or a multiple of the PRF of the resonator.

Abstract: A tunable laser is provided, including: a multiple ring resonator that is formed by coupling ring resonant elements having different optical path length from each other; an input/output-side waveguide connected to one of the ring resonant elements; a reflection-side wave guide connected to another one of the ring resonant elements; a PLC substrate on which the multiple ring resonator, the input/output side waveguide, and the reflection-side waveguide are formed; a high reflection film provided to the reflection-side waveguide; an SOA connected to the input/output-side waveguide; film heaters and a phase control region of the SOA for changing the resonant wavelength of the multiple ring resonator; and a light-receiving element for detecting the resonant wavelength of the multiple ring resonator in a thru port of a directional coupler.

Abstract: A fiber Chirped Pulse Amplification (CPA) laser system includes a fiber mode-locking oscillator for generating a laser for projecting to a fiber stretcher for stretching a pulse width of the laser wherein the stretcher further comprising a Photonic Bandgap (PBG) fiber having a lower nonlinearity and an abnormal dispersion than a solid core fiber for connecting and transmitting a laser from the stretcher to a multistage amplifier for amplifying the laser into an output laser whereby a separate compressor is not required.

Abstract: An in vivo screening assay for identifying an agent that interferes with T cell activation and/or -differentiation and/or modulation of other inflammatory effector cells.

Abstract: A pulse stretcher includes a single pass pulse stretcher. An optical system is arranged around the single pass pulse stretcher. A beam enters the single pass stretcher and is reflected in a helical path using the optical system for multiple passes through the single pass pulse stretcher. The single pass pulse stretcher can include two 90° prisms, with a beam splitter located therebetween. The optical system can include first and second prisms. At least one of the first and second prisms can be a roof prism. The first and second prisms can have at least one surface oriented so as to direct the beam into the helical path. The optical system can have at least one mirror, or a plurality of mirrors.

Abstract: A laser source provides a pulse that is subdivided and replicated into subpulses by a delay structure having a plurality of steps. Each of the subpulses is delayed by one of the plurality of steps and the amount that each subpulse is delayed is different than the others with respect to the pulse. The amount of each delay, and the consequent time delay produced, is greater than the duration of the pulse, which minimizes overlap between adjacent subpulses. The pulse may be transmitted through the delay structure or it may be reflected from the delay structure. Repetition rates of up to hundreds of THz or greater are achieved, and the system and method may be used in Time Division Multiplexing Systems. Information may be transmitted and carried by the subpulses by appropriate modulation techniques.

Abstract: A system and method for reducing peak power of a laser pulse and reducing speckle contrast of a single pulse comprises a plurality of beamsplitters, mirrors and delay elements oriented to split and delay a pulse or pulses transmitted from a light emitting device. The design provides the ability to readily divide the pulse into multiple pulses by delaying the components relative to one another. Reduction of speckle contrast entails using the same or similar components to the power reduction design, reoriented to orient received energy such that the angles between the optical paths are altered such that the split or divided light energy components strike the target at different angles or different positions. An alternate embodiment for reducing speckle contrast is disclosed wherein a single pulse is passed in an angular orientation through a grating to create a delayed portion of the pulse relative to the leading edge of the pulse.

Abstract: This invention pertains to systems for extending the pulse length of pulsed sources of optical radiation. These systems reduce peak optical pulse power without reducing average optical power. The pulse-width extending systems split optical pulses into pulse portions, introduce relative delays among the pulse portions, and then redirect the pulse portions (or portions thereof) along a common axis. Such pulse-width extending systems are especially useful in projection-exposure apparatus for the manufacture of semiconductor devices where short wavelength, high power optical sources tend to damage optical components.

Abstract: A narrow band molecular fluorine laser system includes an oscillator and an amplifier, wherein the oscillator produces a 157 nm beam having a linewidth less than 1 pm and the amplifier increases the power of the beam above a predetermined amount, such as more than one or several Watts. The oscillator includes a discharge chamber filled with a laser gas including molecular fluorine and a buffer gas, electrodes within the discharge chamber connected to a discharge circuit for energizing the molecular fluorine, and a resonator including the discharge chamber for generating a laser beam having a wavelength around 157 nm. Line-narrowing optics are included intra- and/or extra-resonator for reducing the linewidth of the laser beam to less than 1 pm. The amplifier may be the same or a different discharge chamber, and optical and/or electronic delays may be used for timing pulses from the oscillator to reach the amplifier at a maximum in the discharge current of the amplifier.

Abstract: A method and apparatus are provided for temporally stretching and smoothing of the pulses of an output beam of excimer and lithography lasers. The method and apparatus are based upon providing an optical delay line or circuit having a plurality of optical reflectors and a plurality of beam recombiners or splitters so arranged as to divide the pulse into numerous portions which vary in their travel time through the circuit. As a result, the energy of the incident pulse is greatly stretched and smoothed.

Abstract: A laser oscillation device, which has an optical fiber where laser ion is doped; an excitation emission element that generates one laser beam including multiple wavelength components by exciting the laser ion in the optical fiber by light emission; a total reflection element that is located at one end of the optical fiber and reflects uniformly laser beam with multiple wavelengths; a separation optical element that is located at another end of the optical fiber and separates laser beam into beams with multiple wavelengths; and a plurality of partial reflection element that reflect separately laser beams with multiple wavelengths separated by the separation optical element.

Abstract: In the present invention, methods and apparatus for making efficient cladding pumping fiber lasers is disclosed. In particular, new fiber cladding geometry and new method of coupling pumping laser into an optical fiber are disclosed. Both aspects of the present invention will facilitate the realization of high-efficiency and high-power fiber lasers. In the present invention, cladding boundary geometry structures that can prevent the formation of local modes are disclosed. Besides the cladding geometry, methods for efficient coupling of diode lasers into a laser fiber for high power injection are also disclosed. Essentially, the new methods make it possible to transmit diode laser beams for a long distance with substantially the same brightness.

Abstract: A method of and apparatus for measuring chirp passes an input modulated optical signal through a Waveguide Grating Router (WGR) and processes the signals from adjacent WGR output ports in an oscilloscope, to obtain the real-time dynamic chirp measurements of the modulated optical signal.

Abstract: A tunable time plate device for providing a continually adjustable time delay between two linearly polarized laser pulses .omega..sub.1 and .omega..sub.2. The device comprises a time plate made of a parallel flat birefringence crystal having a principal axis of refractive index n.sub.z parallel to its surface, and a principal axis of refractive index n.sub.x having an angle .phi. to its surface normal. The time plate is rotatably mounted such that it is rotatable about its n.sub.z principal axis for tuning a time delay between the two laser pulses as they travel through the time plate which is a function of an incident angle .theta. between its surface normal and the propagation direction of the laser pulses. The time delay therefore can be continually adjusted by rotating said time plate to change said incident angle .theta..

Abstract: A hybrid type passively and actively mode-locked laser scheme is disclosed, in which not only the capability of producing ultra-short optical pulses by the conventional passively mode-locked optical fiber laser scheme is utilized, but also the repetition rate variation capability and the optical pulse synchronization capability of the conventional actively mode-locked laser scheme are utilized. Consequently, all the advantages of the two conventional laser schemes are obtained in the present invention. Specifically, two loops are coupled together, and one of the two loops consists of a non-linear amplifying loop of the existing passively mode-locked scheme, while the other loop includes an optical modulator and an optical gain medium for the loop to perform the function of an actively mode-locked scheme. Further the other loop includes a time delay line so as to adjust the laser oscillation repetition rate.

Abstract: A light pulse generator is disclosed comprising an optical main-loop, a pumped-light source, a delay optical fiber, and an optical switch controller. The optical main-loop circulates a light and includes a light mixer, a light isolator, an erbium-doped optical fiber, an optical switch, a light divider, and an optical fiber coupler. The pumped-light source generates a pumped-light and introduces the pumped-light into the optical main-loop through the light mixer. The terminals of the delay optical fiber are connected to the optical fiber coupler so as to form an optical sub-loop for spreading a pulse width of a light pulse circulating in the optical main-loop. The optical switch controller switches the optical switch to an ON-state. As a result, a positive feedback amplification is carried out in the optical main-loop and an output light pulse having a sufficiently long pulse width and sufficiently high power is picked up from the optical loop through the light divider.

Abstract: A tunable source of narrowband coherent radiation comprises a pulsed pump laser (10), an optical parametric oscillator or amplifier (12) and a so-called master oscillator (14). The narrowband output radiation of the master oscillator serves as seed radiation which is injected into the optical parametric oscillator or amplifier (12). In order to obtain a beam profile of the emitted output radiation as homogeneous as possible, optically imaging elements (28) are arranged in an optical delay line (24) for the partial pulses which pump the optical parametric oscillator or amplifier, which transform the spatial beam profile at the output (30) of the pump laser (10) with respect to amplitude, phase and, preferably, the divergence, too, into the crystal of the optical parametric oscillator or amplifier.

Abstract: A device for extending the duration of a light pulse by a factor of an integer or by a factor which differs from an integer. The light pulse is passed through a device which divides the initial beam into a number of parts, where the first part passes unhindered while the subsequent parts of the beam are retarded and pass through the system after various delay periods, resulting in the desired extension of the pulse duration. The basic components of the novel device are spherical mirrors facing each other, a special reflector and a translation plate.

Abstract: A dispersive, optical delay line for frequency modulated light wave pulses, especially laser waves, comprises a first optical grating and a second optical grating that are parallel to each other, separated by a distance d and localized with a pitch a on the surface of a material that has an index N and is transparent to light waves. An incident wave .SIGMA. is diffracted at an angle .theta.' greater than the limit angle of refraction by transmission through the first and second optical gratings, the angle of emergence from the second grating being also equal to .theta.'. The values of the parameters N, .theta.', a and d are chosen so that a variation in delay time .DELTA.t.sub.R of the pulse through the line corresponds to a modulation bandwidth .DELTA.f of the pulse in a quasi-linear domain. Application to compression/expansion to obtain high-power or very short laser pulses.

Abstract: A fiber laser for producing high energy ultrashort laser pulses, having a positive-dispersion fiber segment and a negative-dispersion fiber segment joined in series with the positive-dispersion fiber segment to form a laser cavity. With this configuration, soliton effects of laser pulse circulation in the cavity are suppressed and widths of laser pulses circulating in the cavity undergo large variations between a maximum laser pulse width and a minimum laser pulse width during one round trip through the cavity. The fiber laser also provides means for modelocking laser radiation in the laser cavity, means for providing laser radiation gain in the laser cavity, and means for extracting laser pulses from the laser cavity.

Abstract: The invention relates to a programmable transverse filter required for the matched filtering of signals with very wide passband. The signals to be filtered modulate one or more optical carriers (F1) in a modulator (MOD). Each carrier is distributed over several channels by a distributor (DIV). A delay creation circuit (CR1 to CRn) is provided in each channel. These channels are next summed after having been correctly delayed and assigned a coefficient characteristic of the signal to be detected.

Abstract: A wavelength controlled optical true time delay generator (14) utilizes passive switching to direct an optical beam to different length paths depending on the input wavelength. In one embodiment a dispersive element (20) is used to reflect the input beam at different angles depending on the incident wavelength. Different optical paths are then provided for the light reflected at different angles. In another embodiment, an optical fiber (50) is provided with reflective gratings (52), each of which are reflective at different wavelengths. The gratings (52) are positioned at different lengths along the optical fiber (50) to provide for different path lengths of light reflected by the gratings and back down the optical fiber (50) to an optical output (38). The true time delay generator (14) provides for a true time delay of any length in a low loss switching mechanism which is relatively inexpensive and compact.

Abstract: A system that modifies a pulsed or continuous wave light beam of arbitrary frequency bandwidth facilitating optical pulse synthesis and pulse compression while largely conserving light energy. An electro-optic deflector scans a light pulse through an optical system which provides a varying optical path length that is a function of deflection angle. The input light pulse is temporally segmented in incremental or differential portions, each of which has a different transit time to some image plane at the output. The temporal portions are then recombined at the output to produce a new optical signal.

Abstract: A method for formatting a laser beam pulse (20) using one or more delay loops (10). The delay loops (10) have a partially reflective beam splitter (12) and a plurality of highly reflective mirrors (14) arranged such that the laser beam pulse (20) enters into the delay loop (10) through the beam splitter (12) and circulates therein along a delay loop length (24) defined by the mirrors (14). As the laser beam pulse (20) circulates within the delay loop (10) a portion thereof is emitted upon each completed circuit when the laser beam pulse (20) strikes the beam splitter (12). The laser beam pulse (20) is thereby formatted into a plurality of sub-pulses (50, 52, 54 and 56). The delay loops (10) are used in combination to produce complex waveforms by combining the sub-pulses (50, 52, 54 and 56) using additive waveform synthesis.

Abstract: An optical wavelength shifter shifts a wavelength of light over a wide range without need for using a large peak pump pulse. A nonlinear optical medium having a nonlinear refractive index is disposed interiorly of a laser resonator. A pump pulse and a light to be modulated are incident on a nonlinear optical medium to phase shift the light. With the provision of a timing delay unit, the timing at which the light to be modulated is incident on the nonlinear optical medium is delayed with respect to the timing at which the pump pulse is incident thereon.

Abstract: Structure is disclosed for the ablation of material by the use of a laser beam wherein the laser provides a beam which is directed through an illumination and projection optical system for imaging on the material which is to be ablated. In the present invention the peak power of the laser beam is adjustable. The laser beam peak power adjustment structure includes a laser that provides a pulsed beam. The laser beam is directed into a beam splitter wherein the laser beam is split into two beam components. The first beam component passes through beam splitter with negligible or no delay, then passes through a quarter waveplate and impinges on a first mirror which reflects it back to the beam splitter. The second beam component is directed at an angle of 90 degrees by the beam splitter and toward a second mirror. The second mirror is at a predetermined distance from the beam splitter which introduces a total predetermined delay for the reflected second beam component as it is directed back to the beam splitter.

Abstract: Apparatus (20) for increasing the length of a laser pulse to reduce its peak power without substantial loss in the average power of the pulse. The apparatus (20) uses a White cell (10) having a plurality of optical delay paths (18a-18d) of successively increasing number of passes between the field mirror (13) and the objective mirrors (11 and 12). A pulse (26) from a laser (27) travels through a multi-leg reflective path (28) between a beam splitter (21) and a totally reflective mirror (24) to the laser output (37). The laser pulse (26) is also simultaneously injected through the beam splitter (21) to the input mirrors (14a-14d) of the optical delay paths (18a-18d). The pulses from the output mirrors (16a-16d) of the optical delay paths (18a-18d) go simultaneously to the laser output (37) and to the input mirrors ( 14b-14d) of the longer optical delay paths. The beam splitter (21) is 50% reflective and 50% transmissive to provide equal attenuation of all of the pulses at the laser output (37).

Abstract: A multiple-stage optical Kerr gate system for gating a probe pulse of light. In a first embodiment, the system includes at least two optical Kerr gates, each Kerr gate including a polarizer, an optical Kerr cell actuable by a pump pulse, and an analyzer. In a second embodiment, at least one of the Kerr cells may be eliminated by arranging the respective sets of polarizers and analyzers so that they share a common Kerr cell. Gated pulses obtained using the present system typically have a signal to noise ratio that is at least 500 times better than that for gated pulses obtained using a single optical Kerr gate system. The system of the present invention may also include means for causing the pump pulse to arrive at the second Kerr cell (in the case of the first embodiment) or at a single Kerr cell a second time (in the case of the second embodiment) non-synchronously with the arrival of the probe pulse thereat.

Abstract: A microwave active element is connected in series to a drive circuit of a laser light emitting element and the laser light emitting element is caused to operate as a microwave resonator as viewed from the microwave active element. Laser light from the laser light emitting element is delayed by a delay controller and fed back to the laser light emitting element to control its delay time, thereby controlling the microwave resonance frequency. At the resonance frequency the microwave active element oscillates pulses and provides a microwave signal to its output terminal. The laser light emitting element is driven by a current flowing across the microwave active element and repeatedly emits, at its pulse oscillation frequency, laser light pulses of spectral frequencies which bear higher harmonic relation to the self-oscillation frequency of the microwave active element. By frequency sweeping the resonance frequency of the microwave resonator, the frequency of the laser light can be frequency swept.

Abstract: A system for the generation of modulated optical signals, wherein to the d.c. bias current of a semiconductor laser (1) associated with an opto-electronic feedback circuit (2) including a delay, there are superimposed the variations of a current obtained by detecting an optical signal resulting from the combination of an optical, amplitude-modulated input signal and of the optical signal present in the feedback circuit. By a suitable choice of the modulation frequency (f2) of the input signal and of the low-frequency gain (B) of the feedback loop (2), the laser output signal is amplitude-modulated at a frequency equal to the modulation frquency (f2) of the input signal.

Abstract: For use, e.g., in the compensation of frequency dispersion in the course of transmission of an optical signal, a pulse-shaping device is provided with a suitably shaped nonplanar mirror (16). When spatially spread-out frequency components--produced, e.g., by a grating (14)--are reflected from such mirror, a frequency-dependent phase shift is introduced; for example, such phase shift may be a third-order function of frequency. Upon recombination of frequencies, a shaped pulse is obtained. Furthermore, third-order compensation can be used to compress amplified light pulses, e.g. as produced by a semiconductor gain medium (80, 81).

Abstract: An optical pulse compressor having a single deflecting dispersive optical element in the form of a diffraction grating (10) or prism for temporal compression of an optical pulse, the frequency of which increases during the pulse duration. An elongated target (T) for receiving the compressed pulse is arranged in parallel with an output surface of the grating or prism. To increase the inclination of the pulse front for effective synchronous travelling wave excitation of the target the output surface of the diffraction grating or prism can be interfaced by an immersion medium or the beam path can be made to converge in the plane containing the target by a cylindrical lens or a reducing imaging optical system can be arranged between the grating or prism and the target.

Abstract: A reading device operates by the placing in interference of a reference signal, in the form of a fundamental wave train, with delayed wave trains constituting the useful signal. The device comprises an interferometer, a first branch (32) of which is traversed by at least said fundamental wave train (14), the first branch (32) being equipped, with means (37, 67, 87) for the generation of quantified delays of said fundamental wave train (14) with means (39) for the generation of a continuously variable delay of said fundamental wave train (14) over a range about each quantified delay value.

Abstract: A highly repetitively pulsed laser stabilizing device which comprises a laser resonator, a feedback system for optically delaying an optical pulse emitted from the laser resonator and returning it in such a manner that it is superposed on an optical pulse in the laser resonator, and a feedback system control section that monitors one of the optical pulses of the laser resonator and feedback system, and controls the optical path length of the feedback system so that the monitored optical pulse is optimum in intensity.

Abstract: A pulsed gas laser having two spaced optical resonators each associated with a pair of high voltage electrodes. The first and second pairs of electrodes are positioned within a common plasma chamber including means for circulating a laser gas successively between the two pairs of electrodes. A common heat exchanger removes the heat energy from the two regions of plasma excitation. A high voltage pulse generator connected to the electrodes includes timing means for delaying the application of high voltage pulses to the second pair of electrodes, the delay being either (a) less than the time required for an acoustic shock wave to travel through the lasing gas from the first to the second pair of electrodes or (b) longer than the time required for the shock wave created by the discharge of the first pair of electrodes to die out. Each optical resonator is provided with an adjustable mirror arranged to reflect laser pulses to and from a mirror grating.

Abstract: Optical systems, using volume holographic elements (gratings) having geometries which tailor the spatio-temporal dispersion of the optical pulses for the system. The input optical pulse is characterized by a frequency variation across the temporal profile of the pulse. The various frequency components of this pulse are first dispersed by at least one grating which may be of the blazed reflection or holographic volume transmission type. The resultant dispersed light is then diffracted by a holographic volume grating which imparts the desired temporal dispersion characteristics to the pulse. The shape of the holographic element will vary according to the input pulse frequency profile as formed by varied chirping techniques. A grating stage may then be repeated, preferably with additional elements in mirror symmetry to the first or by retro-reflection, in order to recombine the spatially dispersed pulse components into an exiting pulse which may be of vastly compressed temporal profile.

Abstract: A mode dependent, optical time delay system for electrical signals having a highly multi-mode optical fiber having a step index profile in optical alignment with an optical source which is capable of converting an incoming electrical signal into an optical signal. By incorporating within the system a number of different components to alter or control the mode angles of the incoming optical signal, the resultant optical output signal is time delayed as it propagates through the optical fiber. This optical output signal is thereafter converted into an electrical output signal which is also time delayed in direct relation to the mode angle of the optical signal propagating through the optical fiber.

Abstract: A high-power flowing-gas laser comprises an outer housing, an optical system including a laser channel within the housing, and an impeller for producing a flow of gas through the laser channel. The laser channel is folded so as to be constituted of a plurality of legs disposed in a polygon, preferably square, configuration, there being a gas flow channel for each laser channel leg and including an axially-extending inlet section and a radially-extending outlet section, the latter being formed with aligned laser openings for accommodating the laser beam of the respective laser channel leg. The laser further includes an internal partition wall between the outlet end of the impeller and the inlet ends of the gas flow channels for confining the gas flow from the impeller to the inlet ends of the gas flow channels, which partition substantially precludes gas flow into the gas flow channel legs through the aligned laser openings at the outlet sections of the gas flow channels.

Abstract: The invention is to provide a gas laser in which a discharge tube of a double-tube construction comprising a inner tube and an outer tube of a relatively large diameter is employed, a tubular discharge space filled with a gas mixture is formed between the inner tube and the outer tube, a gas mixture cooling passage is formed within the discharge space, and a pair of mirror groups are disposed at both ends of the discharge space, each mirror group comprising a plurality of mirrors arranged in the circumferential direction. The respective mirrors are arranged in such a manner that a laser beam is reflected by the mirrors to go and return in the discharge space several times and each path of the laser beam between the corresponding two mirrors obliquely intersects the central axis of the discharge space.

Abstract: A high-power flowing-gas laser comprises a laser channel folded to include at least two legs angularly disposed to each other in a common plane and having a single folding mirror between them such that the laser rays through one leg, on the upstream side thereof with respect to the gas flowing transversely across that leg, are reflected by the folding mirror so as to be transposed to the downstream side of the other leg with respect to the gas flowing transversely across the other leg. A number of embodiments are described wherein the laser channel is folded to include four or other even number of legs according to a polygonal configuration, there being a separate flowing gas channel for each leg, all the gas channels directing the gas flow radially inwardly to a common collection region. Among the advantages provided by the described constructions are compensation for phase distortion and amplitude variations, and maximum laser channel length and laser output for a given system size and volume.

Abstract: In the present invention, methods and apparatus for making efficient cladding pumping fiber lasers is disclosed. In particular, new fiber cladding geometry and new method of coupling pumping laser into an optical fiber are disclosed. Both aspects of the present invention will facilitate the realization of high-efficiency and high-power fiber lasers. In the present invention, cladding boundary geometry structures that can prevent the formation of local modes are disclosed. Besides the cladding geometry, methods for efficient coupling of diode lasers into a laser fiber for high power injection are also disclosed. Essentially, the new methods make it possible to transmit diode laser beams for a long distance with substantially the same brightness.