181 results about "Pulse amplifiers" patented technology

A compact signal source including: a semiconductor-based, pulsed optical energy source for providing a series of pulses at a given frequency; a selector being optical fiber coupled to the pulsed optical energy source and for down-selecting the pulses to a lower frequency; a stretcher being optical fiber coupled to the selector and for temporally stretching the selected pulses; at least one semiconductor-based optical amplifier being optical fiber coupled to the stretcher and for amplifying the selected pulses; a compressor being optical fiber coupled to the at least one semiconductor-based amplifier and for temporally compressing the amplified, stretched, selected pulses; and, a portable housing containing the pulsed optical energy source, stretcher, at least one semiconductor-based optical amplifier and compressor.

Methods, devices and systems for generating ultrashort optical linear chirped pulses with very high power by amplifying the pulses so that their temporal duration is longer than the storage time of the amplifying medium. The additional gain factor is related to the ratio of the storage time to the stretched pulse. A preferred embodiment connects a mode locked laser source that generates optical pulses whose duration is stretched with a chirped fiber Bragg grating. Embodiments include methods, devices and systems causing an extreme chirped pulse amplifier (XCPA) effect in an oscillator.

The invention relates to a pocket type digital radiation dosemeter comprising of a detector, which converts the ionisation in the detector caused by the incidence of ionising radiation of certain energy range into electrical impulses, a low power pulse amplifier, that amplifies the electrical pulses from the detector to detectable amplitudes, a discriminator circuit, that is used to reject pulses of origin other than those caused by the ionising radiation, a programmable divider circuit for calibrating the dosemeter, an electronic counting circuit and a six digit LCD display. The sensitivity of the dosemeter is 1 count per μSv (micro Sievert) and the accuracy is within ±15% from 60 keV to 1.25 Mev of X or Gamma radiation. A metallic energy compensation filter and a discriminator threshold modulation circuit are used to provide uniform response within ±15% from 60 KeV to 1.25 MeV. The Digital display indicates at any instant the total X or Gamma radiation dose, in μSv, received by the dosemeter since the time at which the dosemeter was switched on. The dosemeter is designed for very low power consumption and is powered by two coin type Li batteries (Type CR2320). It is capable of over 500 hours of continuous operation before having to replace the batteries. A blinking LED indicates low battery condition when 8 hours of battery life is still left. The entire circuitry and the battery holder are mounted on a single printed circuit board. Surface mount components are used to make the unit compact. The dosemeter is compact (110 mm L×30 mm W×14 mm H excluding Clip) and light in weight (60 gm).

An ultrashort pulse amplifier produces high-power ultrafast laser pulses. Pulses first have net negative (i.e. blue to red) chirp applied, and are then amplified in a laser amplifier. After amplification, the pulses are compressed using propagation through a block of material or other convenient optical system with a positive sign of chromatic dispersion. High-order dispersion correction may also be included.

The invention relates to distributed optical fiber sensing technology and provides a distributed optical fiber sensing device and a method based on a Brillouin Er-doped fiber laser. The distributed optical fiber sensing device and the method based on the Brillouin Er-doped fiber laser comprise a narrow linewidth pump laser, an optical fiber coupler, an optical pulse generator, an optical pulse amplifier, an optical fiber amplifier, an optical fiber circulator, sensing optical fibers, a Brillouin Er-doped fiber laser, an optical fiber isolator, an photoelectric detector and a signal collecting and processing device. Brillouin gain optical fibers of the Brillouin Er-doped fiber laser are wound on piezoelectric ceramic, and Brillouin frequency shift is changed through adjusting temperature of the Brillouin gain optical fibers and / or convergent-divergent of the piezoelectric ceramic. According to the distributed optical fiber sensing device and the method based on the Brillouin Er-doped fiber laser, pump light needed by a Brillouin optical time domain analysis meter (BOTDA) and detecting light which is provided with the Brillouin frequency shift and is tunable are obtained with the same light source, and no additional laser or high-speed modulator and microwave modulating source of the high-speed modulator is needed. The system cost is lowered, the system structure is simplified, and the system structure is enabled to be compact and convenient to pack.

Methods, devices and systems for generating ultrashort optical linear chirped pulses with very high power by amplifying the pulses so that their temporal duration is longer than the storage time of the amplifying medium. The additional gain factor is related to the ratio of the storage time to the stretched pulse. A preferred embodiment connects a mode locked laser source that generates optical pulses whose duration is stretched with a chirped fiber Bragg grating. Embodiments include methods, devices and systems causing an extreme chirped pulse amplifier (XCPA) effect in an oscillator.

A system and method for detecting a milling endpoint on a semiconductor sample by directing an ion beam from a focused ion beam (FIB) apparatus at the sample and using charge pulse detection electronics (CPDE) components to generate a distribution curve on a histogram display. A preferred configuration of the CPDE components includes a charge preamplifier, a pulse amplifier, a pulse shaper, and a multichannel analyzer (MCA).

The invention relates to an optical pulse amplifier comprisinga first optical fiber amplifier adapted to receive an input pulse,a splitter connected to said first optical fiber, said splitter having a plurality of outputs;a plurality of optical fiber amplifiers, each optical fiber amplifier being connected to one of said plurality of outputs, said plurality of optical fiber amplifiers generating a plurality of output pulse signals.The optical pulse amplifier of the invention has the advantage that it can produce high peak and high average power.

The system comprises: a sensing system and a host machine. When the system is at a defenses state and the radio vibration probe of the sensing system detects an invader attempting to open the door, the host machine doesn't give an alarm but only giving three bell sounds, and meanwhile enters into a pre-alarm state; if the damage goes on, then the host machine gives the alarm and dials the phone number of the master; if in a preset time length, there is no second trigger, the host machine enters the defense state again. After combining the infrared probe with the micro vibration probe to build a logic relation, only at the condition in which both probes are simultaneously triggered, then the host machine gives an alarm. The invention is an energy-saving system; one battery can keep a 1-2 year service time.

Characters of the invented circuit are that each single-phase inverter includes following parts: voltage measuring apparatus for measuring voltage between two ends of capacitance at DC side of inverter; evaluator of minimum capacity voltage for determining minimum value among capacity voltages at DC side of each inverter, and the minimum value being as reference voltage of pulse width regulator; the pulse width regulator carrying out error adjusting between signal of measured capacity voltage at DC side and reference voltage; pulse amplifier for magnifying signal of pulse width modulation and adjusting voltage between two ends of capacitance at DC side of inverter. The invented circuit can compensate unbalanced voltage at DC side of reactive generating device, making equipment operate normally.

The invention discloses a pulse modulation drive circuit of a miniature semiconductor laser. The pulse modulation drive circuit comprises an external power supply interface circuit, a pulse generating circuit, a pulse shaping circuit, a high-speed pulse amplifier circuit, and a laser driver main power generation circuit. When the provided pulse modulation drive circuit is applied to the semiconductor laser, the power consumption and heating value of the semiconductor laser can be reduced; and the circuit has a small size and is suitable for a hand-held semiconductor laser with the small physical space. Meanwhile, the circuit has characteristics of simple structure, reliable performance, fast pulse response, high pulse output power, and high anti-interference performance.

A fuse detection device based on pulse laser ranging principles mainly comprises a power supply, a laser, an optical emission system, an optical receiving system, a detector, a pulse amplifier, a signal processing and decision circuit, and the like. According to the fuse detection device, pulse laser fuse detection is adopted, the fuse detection device has confidentiality and anti-interference performance as the laser has good monochromaticity, the locating accuracy of fuse is largely increased as the laser has good directionality, and the sensitivity of the fuse is increased as the laser has high luminance, and therefore the fuse detection device has good anti-electromagnetic interference capability, working safety, reliability and high ranging accuracy, and is widely applied in the aviation field.

The invention discloses a method for improving a signal-to-noise ratio of femtosecond laser by using chirp matched optical parametric chirped pulse amplification and a device thereof, which belong to the technical field of ultra-short pulses. The method comprises the following steps of: firstly, stretching the femtosecond laser with a signal-to-noise ratio to be improved output by a femtosecond laser light source into chirp signal light; secondly, performing high magnification on a signal and performing low magnification on a noise by using the chirp matched optical parametric chirped pulse amplification so as to improve the signal-to-noise ratio of the chirp signal light; and finally, compressing the chirp signal light into femtosecond laser with a high signal-to-noise ratio by using an optical pulse compressor. The device for implementing the method comprises a femtosecond laser light source, a femtosecond laser, a first non-linear optical crystal, a second non-linear optical crystal, a first light pulse stretcher, a second light pulse stretcher, an optical pulse amplifier, an optical pulse compressor, a first dichroic mirror and a second dichroic mirror. The method and the device of the invention can not only improve the signal-to-noise ratio of the femtosecond laser effectively, but also realize high-efficient amplification of the femtosecond laser.

There is provided a parabolic pulse amplifier for amplifying a pulse light signal. The amplifier comprises an ytterbium-doped amplification waveguide pumped using a pump source with a pump central wavelength substantially offset from the absorption transition peak wavelength. The pump wavelength is selected such that the absorption coefficient of pump light and the gain coefficient of the signal are substantially equal in the amplification waveguide such that the amplification gain is distributed substantially uniformly along the amplification waveguide.

The invention discloses a multi-purpose bidirectional passive mode-locked full-fiber laser system and aims to solve a technical problem that it is difficult for a convention fiber laser device to output two types of ultra-short optical pulses simultaneously. The system comprises a pumping source (1), a wavelength division multiplexer (2), an erbium-doped gain fiber (3), a 2*2 output coupler (4), a first 3dB optical coupler (5), a second 3dB optical coupler (6), a first polarization-dependent isolator (7), a first polarization controller (8), a second polarization-dependent isolator (9), a second polarization controller (10), a dispersion compensation fiber (11) and a single-mode fiber (14). The 2*2 output coupler (4) outputs a bidirectional mode-locked pulse. The first output end (12) of the 2*2 output coupler (4) is connected with the single-mode fiber (14) located outside a cavity and is used for the out-of-cavity time-domain compression of the output pulse to obtain a high-peak-power ultra-short pulse. The second output end (13) of the 2*2 output coupler (4) directly outputs a high-energy dissipative soliton resonance pulse. The system is low in cost and wide in application range, and can be used as a high-peak-power femtosecond pulse light source and a high-energy picosecond and nanosecond pulse light source, and can also be used as a seed source of a high-energy pulse amplifier.

The invention discloses a mid-infrared chirped pulse amplifying device. The mid-infrared chirped pulse amplifying device comprises a femtosecond laser, a synchronous narrowband picosecond laser, a beam splitter, a near-infrared pulse stretcher, a non-linear frequency converter, an optical parametric chirped pulse amplier and a mid-infrared pulse compressor. Due to the fact that grism pairs and grating pairs are matched with each other to serve as the pulse stretcher and the pulse compressor, usage of a mid-infrared pulse stretcher is avoided, residual third-order dispersion in compression pulses in the process that the grating pairs serve as the pulse stretcher and the pulse compressor is eliminated, and the mid-infrared chirped pulse amplifying device is particularly suitable for generation of mid-infrared ultra-short ultra-strong pulse lasers with the frequency lower than hundreds of femtoseconds.

A class D amplifier includes a noise-shaping modulator, a pulse width modulator, and a pulse amplifier. The noise-shaping modulator receive a pulse code modulated (PCM) signal and produces an oversampled PCM signal. The pulse width modulator produce a pulse width modulated (PWM) signal from the oversampled PCM signal. The pulse amplifier amplifies the PWM signal to produce an amplified PWM signal. The PWM uses a lookup table to convert from PCM to PWM. A compensation circuit optimizes amplifier performance. An optional demodulator filter converts the amplified PWM signal to an analog signal. The amplifier is ideal for integrated audio applications.

The invention discloses an optical fiber chirped pulse amplifier for ultra-short laser pulse output, which has the advantages of high pulse repetition rate, high power and ultra-short laser pulse output and belongs to the technical field of optical information. The optical fiber chirped pulse amplifier adopts an optical fiber type concave attenuating long-period fiber grating as a seed laser pulse of a high-power chirped femtosecond laser pulse amplifier or a spectral shaping component of a laser pulse amplified by a preamplifier, thereby eliminating the gain spectrum narrowing effect caused during amplification of the high-power chirped femtosecond laser pulse optical-fiber amplifier, increasing the spectral bandwidth of the amplified laser pulse. The laser pulse with smaller pulse width and higher peak power can be obtained through compression. The high-power chirped femtosecond laser pulse amplifier which has the advantages of high repetition rate, high power, simple structure and high efficiency and can be fully made of optical fiber is applicable to such industrial fields as precision machining, precision lithography, laser fusion and the like of semiconductor devices and metal materials and the basic scientific research such as biomedical imaging.

A super Gaussian pulse generation method on the basis of gain reshaping includes the following steps: firstly, a wideband linear chirp laser pulse is generated, and the central wavelength of the wideband linear chirp laser pulse is adjusted to be longer than the intrinsic emission line peak wavelength of the doped gain ion of an optical fiber amplifier; secondly, the gain-narrowed lower triangular chirp laser pulse is obtained after the linear chirp laser pulse is gain amplified by a pre-amplifier selected with the gain coefficient spectral lines all presenting triangular shapes; finally, the super Gaussian pulse is formed by injecting the lower triangular chirp pulse into a main amplifier selected with the gain optical fiber length being 1 to 3 times of that of the pre-amplifier and the central wavelength of the gain spectrum lines being longer than the pre-amplifier. The device capable of realizing the method comprises an optical fiber femtosecond laser oscillator (9-1), a dispersion compensator (9-2), an optical fiber self-similarity pulse amplifier (9-3), a positive dispersion optical fiber pulse stretcher (9-4), a frequency spectrum filter (10), and a front optical fiber amplifier (11) with at least one stage and a main optical fiber amplifier (12).

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.

A pulse detection laser is provided. The pulse detection laser includes a single frequency oscillator, a continuous pre-amplifier, and a pulsed amplifier. The single frequency oscillator generates a seed laser beam and is optically coupled to the continuous preamplifier. The continuous pre-amplifier amplifies the seed laser to produce an intermediate power laser beam. A pulsed amplifier optically coupled to the continuous pre-amplifier receives the intermediate power laser beam and amplifies the intermediate power laser beam to produce a pulse detection laser beam. One task of this pulse detection laser is to illuminate ultrasonic displacements. Light from the laser is scattered, collected, and analyzed with an interferometer to demodulate the ultrasonic displacements caused by the return echoes of the ultrasound at the surface of the part.

The invention relates to the technical field of laser, and provides a broadband optical parameter chirped pulse amplifier. The broadband optical parameter chirped pulse amplifier comprises a narrow-band picoseconds laser device, a pulse laser stretcher, an optical coupling mirror, a beam expanding / contracting system, periodic poling crystal, a spectroscope and a pulse laser compressor. The periodic poling crystal with the periodic domain inversion structure is used for separating generated idler frequency light from chirped pulse laser / pumping light to inhibit energy backflow after the broadband optical parameter chirped pulse amplifier is in a saturated amplification state, and therefore broad optical parameter chirped pulse amplification of a broadband is achieved. The broadband optical parameter chirped pulse amplifier is capable of inhibiting backflow of signal light energy and has extremely wide gain bandwidth, benefited from synchronous optimization of pulse energy (conversion efficiency) and pulse width (gain bandwidth), outputable peak-peak power of the broadband optical parameter chirped pulse amplifier is greatly promoted, and performance of the broadband optical parameter chirped pulse amplifier is improved.

A pulse-generating apparatus, comprising a pulse source, an output terminal to which pulses from the pulse source are supplied, and a measuring device for measuring the level of a pulse that will be output from the output terminal at a pre-determined time position; a pulse-generating apparatus, further comprising a device for adjusting the level of the pulse that will be output at the pre-determined time position, based on at least the measured pulse level and the reference pulse level at the pre-determined time position; and a pulse-generating apparatus, wherein the pulse source generates pulses based on at least one parameter, and the adjusting device adjusts the level of the pulse that will be output by updating the parameter, changing the amount of amplification of the amplifier of the pulse source, or changing the amount of attenuation of the attenuator of the pulse source. The parameter may include at least one of the load impedance and the pulse level.

The invention discloses a high-power femtosecond fiber laser device, which comprises a circuit and a light path, wherein the circuit comprises a circuit board, an acousto-optic modulation driver and a plurality of semiconductor diodes as pumps; the light path comprises an oscillator, a first coupler, a first-stage preamplifier, an acousto-optic modulator, a second coupler, a second-stage preamplifier, a separated pulse amplifier, a first pulse compressor, a main amplifier and a second pulse compressor; and the devices of the light path are sequentially connected with one another along the light path. The high-power femtosecond fiber laser device has irreplaceable advantages in the aspects of high-precision laser cutting, high-precision laser deep welding, special material surface treatment and the like; and the specific application comprises sapphire and toughened glass cutting, cardiovascular stent construction, high-precision machining of a thin-film solar cell and the like.

The invention discloses an all-fiber laser system and method for generating a soliton burst mode and aims to solve the technical problem that it is difficult for a conventional fiber laser to directlyoutput a burst-mode soliton pulse. The system includes a passive mode-locked fiber laser (1), an isolator (2), an optical fiber amplifier (3), a photonic crystal fiber (4), a programmable optical filter (5), a first single-mode fiber (6), a coupler (7) and a second single-mode fiber (8) which are successively connected. The all-fiber laser system is simple and compact in structure and good in stability, achieves, by adjusting the filtering bandwidth and the filtering wavelength interval of the programmable optical filter (5), a controllable pulse number inside a soliton cluster and a continuously adjustable pulse repetition frequency at the order of GHz, greatly reduces system cost, can be directly applied to the field of micromachining, and can also be used as a seed source for a high-energy pulse amplifier.

The invention discloses a high time resolution low noise single photon detector based on optical pulse synchronization. The single photon detector comprises an optical pulse generator, an optical fiber coupler, an optical attenuator, an optical delayer, a photoelectric conversion module, a gate pulse amplifier module and a signal extraction module, wherein the optical pulse generator is connected with the optical fiber coupler and divided into two paths, one path is connected with the optical attenuator, the optical attenuator is connected with the optical signal input end of the gate pulse amplifier module, the other path is connected with the optical delayer, the optical delayer is connected with the optical signal input end of the photoelectric conversion module; the output end of the photoelectric conversion module is connected with the electric signal input end of the gate pulse amplifier module; and the electric signal output end of the gate pulse amplifier module is connected with the signal extraction module. The single photon detector uses the optical delayer and the photoelectric conversion module to convert the optical signals to Gaussian electric signals which are used as gate pulse signals, thus the noise of the avalanche photo diode (APD) caused by capacitance effect can be reduced and the signal-to-noise ratio can be increased.

A pulse amplifier with dual-cladding multi-mode optical fibre arranged cylindrically use high-quality low-power pulse laser as seed light source. The external cladding on a tangent line is removed to form a pump window coupled with a strip of internal cladding. A semiconductor laser pump source and a focusing lens are opposite to it. The linearly polarized pulse laser from seed light source is converted to properly polarized pulse laser by 1 / 2 wave plate and 1 / 4 wave plate, which is coupled into one end of optical fibre. After amplified, a high-power laser is output from its another end. Its advantages are compact structure, efficient and uniform pumping, and high output power.