71 results about "Fibre amplifier" patented technology

An optical network and a method of provisioning an optical network are described. The optical network includes a first passive optical network optical line terminal arranged to transmit a first optical signal at a first wavelength, coupled to a first port of a first optical filter arrangement, and a second passive optical network optical line terminal arranged to transmit a second optical signal at a second, different wavelength, coupled to a second port of the first optical filter arrangement. An optical coupler is connected between the second passive optical network line terminal and the second port of the first optical filter arrangement, for coupling a plurality of optical signals at a predetermined set of wavelengths from a third optical line terminal into the second port. A passive optical distribution node, for connection to a plurality of optical network terminations, is coupled to a third port of the first optical filter arrangement for distribution of optical signals between the optical line terminals and the plurality of optical network terminations. The first optical filter arrangement is arranged to pass optical signals at the first wavelength between the first port and the third port and to block optical signals at the second wavelength and the predetermined set of wavelengths between the first port and the third port, and the first optical filter arrangement is further arranged to pass optical signals at the second wavelength and the predetermined set of wavelengths between the second port and the third port and to block optical signals at the first wavelength between the second port and the third port. The second optical signal is at a faster rate than the first optical signal, and the second wavelength and the predetermined set of wavelengths are within an amplification band of a doped fibre amplifier.

To overcome problems of fabricating conventional core-clad optical fibre from non-silica based (compound) glass, it is proposed to fabricate non-silica based (compound) glass optical fibre as holey fibre i.e. one contining Longitudinal holes in the cladding. This removes the conventional problems associated with mismatch of the physical properties of the core and clad compound glasses, since a holey fibre can be made of a single glass composition. With a holey fibre, it is not necessary to have different glasses for the core and cladding, since the necessary refractive index modulation between core and cladding is provided by the microstructure of the clad, i.e. its holes, rather than by a difference in materials properties between the clad and core glasses. Specifically, the conventional thermal mismatch problems between core and clad are circumvented. A variety of fibre types can be fabricated from non-silica based (compounds) glasses, for example: single-mode fibre; photonic band gap fibre; highly non-linear fibre; fibre with photosensitivity written gratings and other refractive index profile structures; and rare-earth doped fibres (e.g. Er, Nd, Pr) to provide gain media for fibre amplifiers and lasers.

The invention discloses a method for self-coherence detection of an optical carrier radio frequency link based on polarization multiplexing. The invention relates to the technical field of optical communication and microwaves. The method is shown in the attached drawing, and comprises a laser source, a vector signal source, a polarization controller, a polarization beam splitter, a polarization multiplexing Mach-Zehnder modulator, a single-mode fiber, an erbium-doped fiber amplifier, a 90-degree optical coupler and a balance photoelectric detector. According to the method, two paths of different radio frequency electric signals are used for respectively carrying out intensity modulation and phase modulation on two optical carriers with orthogonal polarization states in a polarization multiplexing Mach-Zehnder modulator; frequency mixing is carried out through a 90-degree optical coupler; signal processing is performed on the electric signal output by the balance photoelectric detectorto recover an original electric signal; the polarization multiplexing mode is used for improving the utilization rate of spectrum and light source power; self-coherent detection is used at the receiving end; and a local oscillation light source and a complex phase noise elimination algorithm are avoided, so that the system cost is reduced, and the requirement for the line width of the laser is lowered.

Disclosed herein are Low Size Weight and Power efficient Laser Diode pump modules and High Power Fiber Amplifiers incorporating such pump modules for amplifying laser light produced by a seed laser. The pump modules are configured for forced fluid cooling, and are provided with cooling channels that allow for varying combinations of a coolant mass flow rate F of the coolant, a pressure drop P of the coolant, and a steady state temperature T of the laser diodes in the pump modules, uniquely and significantly, and thereby allowing for optimizing such variables for a particular application.

The ultra wideband near infrared luminescent transparent microcrystalline glass disclosed by the invention is the glass that the glass in which transition metal ions are doped contains two or more than two kinds of 1-1,000 nano-microcrystal, and the doping concentration of the transition metal ions is 0.01-5 mol%. Compared with rare-earth ions and crystal material in which transition metal ions is doped, the ultra wideband near infrared luminescent transparent microcrystalline glass of the invention is characterized in that the processing is easy; compared with the rare-earth ions and microcrystalline glass material doping transition metal ions and only containing a single crystal phase, the ultra wideband near infrared luminescent transparent microcrystalline glass has wider infrared bandwidth. The glass of the invention can be used in ultra wideband infrared light sources, ultra wideband fibre amplifiers and tunable lasers.

The invention provides a microwave frequency measuring method and device based on an optics frequency comb, and belongs to the microwave frequency measuring method and device technical field; the method comprises the following steps: dividing a laser signal formed by a laser and with the frequency fc into two parts, and using an unknown RF signal with the frequency fRF to carry out carrier suppression double-sideband modulation for one of the said two parts; beating frequencies of a carrier suppression double-sideband modulation signal and an off resonance light frequency comb on a narrowband photoelectric detector; parsing the frequency spectrum of the beat frequency signals, thus obtaining frequency information and power information of the two beat frequency signals; determining the frequency of the incident RF signal according to determined i, f1, f2 and a formula (7). The measuring device comprises the laser, a first coupler, an intensity modulator, a programmable filter, an erbium doped fiber amplifier, a double parallel modulator, a signal-generator, an electricity coupler, a phase shifter, a photoelectric detector, a frequency spectrograph, a second coupler, a third coupler and a fourth coupler.

The invention aims to provide an erbium-doped fiber amplifier control system. In the hardware structure, the control system can be applied to erbium-doped fiber amplifiers of various functions. The control system comprises a control module, three power control loops, two pump laser driver modules, and one adjustable light attenuation driver module, wherein both an input light power detection end and an output light power detection end of each power control loop are connected with a signal input end of the control module, a drive signal input end of each pump laser driver module is connected with a signal output end of the control module, a drive signal output end of each pump laser driver module is used for connecting with a pump laser of a to-be-controlled erbium-doped fiber amplifier, adriver signal input end of the adjustable light attenuation driver module is connected with the signal output end of the control module, and a driver signal output end of the adjustable light attenuation driver module is used for connecting with a to-be-controlled adjustable light attenuator.

An optical amplifier assembly for submarine applications. The optical amplifier assembly comprises: a first and a second double stage fibre amplifier with respective first and second fibre amplifiers for amplifying optical signals (OS, OS') each propagated on a respective optical fibre, said optical fibres being operated in opposite operating directions (W-E, E-W), and a common pump source comprising a plurality of pump light sources, the common pump source being coupled via a coupler as a co-propagating pump to the first and second fibre amplifiers of the first and second double stage fibre amplifiers. The proposed optical amplifier assembly further comprises a gain flattening filter between the two fibre amplifiers of the first and second double stage fibre amplifiers. Thus the proposed optical amplifier assembly presents an increased efficiency with respect to an output power at a constant pump power and allows to adjust the pump power for maintaining a given output power without excessive NF degradation.

The invention relates to the field of fiber lasers and provides an optical fiber pulse amplifier which can be used for amplifying pulse signals of two bands. The technical scheme includes that a dual-band erbium ytterbium doped fiber optic pulse amplifier comprises a pumping source, a pumping-source pulse driving power source, two different band signal sources, signal source pulse driving power sources, a time-delay control circuit, isolators, a wavelength division multiplexer, a pumping / signal combiner, gain fiber and a fiber end cap. The pumping-source pulse driving power source is used for driving the pumping source to send out laser pumping pulses which are injected into the gain fiber to pump the same via the pumping / signal combiner; synchronizing signals sent out by the pumping-source pulse driving power source are properly delayed through the time-delay control circuit to trigger two signal source pulse driving power sources to drive the two different band signal sources to send out signal pulses respectively; and two signal pulses pass the respective isolators and are coupled together to perform amplifying output via the wavelength division multiplexer. The optical fiber pulse amplifier is mainly applicable to amplification of the dual-band pulse signals.

The inventive fiber amplifier comprises: (a) a first Er-doped fiber provided with a first light-pumping source via a first pump combiner to amplify input optical signals; (b) a second Er-doped fiber provided with a second light-pumping source via a second pump combiner to amplify input L-band optical signals; (c) a C / L splitter provided in the downstream of the first Er-doped fiber for splitting the optical signals into C- and L-bands, respectively, during passage through the C / L splitter; (d) a reflector for transmitting the L-band optical signals split in the C / L splitter toward the second Er-doped fiber and reflecting the transmitted L-band optical signals to flow back toward the second Er-doped fiber; (e) a circulator for introducing the L-band optical signals which are amplified after backward flow from the reflector toward another direction and preventing the backward flow of ASE generated during amplification toward the first Er-doped fiber; and, (f) a C / L combiner for combining the C-band optical signals split in the C / L splitter and the L-band optical signals introduced from the circulator.

This invention relates to a signal source with 1053nm wavelength, high power and narrow line width, which applies a multimode semiconductor packaged by an optical panel at the pump source and a 1053nm single vertical mode DFB laser with the line width of 10-4nm as the weak signal seed optical source, the output end of the semiconductor laser is melted to a pump end of a multimode pump beam synthesizer, the output tail fiber of which is melted to the input end of a double clad fiber amplifier doped with Yb, the output end of which is output by an 8deg. incline wire jumper.

The invention discloses a microwave photon channelization receiving method based on polarization multiplexing optical frequency dispersion and an integrated coherent receiver, and relates to the technical field of microwaves and the technical field of optical communication. The method is as shown in Figure 1 in the specification, and a light source, a radio frequency signal source, a Mach-Zehndermodulator, an optical coupler, an erbium-doped fiber amplifier, an optical band-pass filter, a double-parallel quadrature phase shift keying modulator, a polarization controller and an integrated coherent receiver (ICR) are included. And channelized receiving of four channels can be realized only by using two linearly polarized multiplexed local oscillator optical frequency combs. In addition, according to the method, the problem of mirror image interference existing in the dual-optical-frequency microwave photon channelization receiver is solved by combining ICR with a digital signal processing DSP algorithm. Because no high-frequency electric device is used, the method has the advantages of large bandwidth, high image rejection ratio and the like. Due to the fact that optical carriers are restrained and balance detection is adopted, the method further has the advantage of being high in gain.

The invention relates to a multistage fibre amplifier having a first amplifying fibre (EDFI) and at least one further amplifying fibre (EDF2) connected in series, and also a pump source (2D), a first pump signal (AI) being fed to the first amplifying fibre (EDFI) and a further pump signal (A2) being fed to the further amplifying fibre (EDF2). The multistage fibre amplifier is distinguished by the fact that the further pump signal (A2) is fed to the further amplifying fibre (EDF2) via a power-dependent attenuation element (ZFED). The attenuation element (ZFED) is formed in such a way that, as the pump power increases, small further pump signals are attenuated to a greater extent than large further pump signals. The power-dependent attenuation of the pump signal (A2) fed to the further amplifying fibre primarily results in improvements in the noise figure of the multistage amplifier.; A method for adapting the pump power of the multistage fibre amplifier according to the invention is furthermore specified. This involves a modified feedforward control which advantageously compensates for the delays brought about by the additional fibre on changes in the input signal power. An improved dynamic behaviour of the multistage fibre amplifier is achieved by means of the method according to the invention.

The invention discloses a multi-band linear frequency modulation signal generation method capable of flexibly selecting frequencies, and relates to the technical field of microwaves and the technical field of optical communication. The method is shown in a figure 1 in the specification, and comprises a laser device LD, a dual-polarization binary phase shift keying modulator DP-BPSK, an arbitrary waveform generator AWG, an erbium-doped fiber amplifier EDFA, a polarization controller PC, a polarizer POL and a photoelectric detector PD. Phase modulation is carried out on a local oscillator signal through the DD-MZM1 of the DP-BPSK upper arm, and carrier suppression double-sideband modulation is carried out on an IF-LFM signal through the DD-MZM2 of the DP-BPSK lower arm; the PC is adjusted, the phase difference between the two polarization states is controlled, and then a multiband linear frequency modulation signal can be obtained after POL and photoelectric detection. According to the invention, the electronic bottleneck of the electric field technology is overcome, and the characteristic of flexible frequency tuning is added; multi-band signals are generated at the same time, so that the system has potential application value in a multi-band radar and a distributed radar system.

The invention provides a rectangular optical frequency comb generation system based on an on-chip silicon nitride micro-ring. The system comprises a tunable laser, a first optical coupler, a second optical coupler, an erbium-doped fiber amplifier, a polarization controller, a first optical isolator, a second optical isolator, a Si3N4 micro-ring resonant cavity, a first photoelectric detector, a second photoelectric detector, a third photoelectric detector, a data acquisition unit and a polarizer. Compared with an optical frequency comb based on dissipative optical solitons in a microcavity inthe prior art, the provided system has the following advantages: the comb tooth power of the rectangular optical frequency comb is remarkably more uniform, and particularly, a problem that the edge power of the optical frequency comb is reduced is solved, so that more comb tooth power is maintained at a high level, and the energy conversion efficiency of the optical frequency comb and the absoluteenergy of the comb teeth are remarkably improved.

The invention relates to the field of fiber laser, in particular to a mid-infrared 4mu m fiber laser amplifier based on a Dy-doped chalcogenide glass fiber, which mainly structurally comprises a pumping source, a focusing lens, a Dy-doped chalcogenide glass fiber, a dichroic mirror, a reflector and a signal source. According to the 4-micron waveband intermediate infrared optical fiber amplifier based on the chalcogenide gain optical fiber, stable, high-gain, high-signal-to-noise-ratio and wavelength-continuously-adjustable 4-micron waveband amplified signal laser output is achieved, and the problem that the output power of a current 4-micron waveband laser light source is low is solved.

The invention discloses a forward Brillouin fiber laser based on stimulated Raman. The forward Brillouin fiber laser comprises a tunable single-frequency laser, an erbium-doped fiber amplifier, a polarization controller, an optical coupler, a single-mode fiber, a polarization beam combiner, a photodiode, a frequency spectrograph and a spectrograph. The forward Brillouin fiber laser based on stimulated Raman has the advantages and positive effects that compared with an existing Brillouin fiber laser, by utilizing the stimulated Raman R0m mode which is equal in frequency interval and related tothe fiber core diameter, the design flexibility of a resonant cavity is improved, and the Brillouin fiber laser with irrelevant cavity length is realized.

The invention discloses a precision compensation photonics-assisted frequency measurement device based on interference and power cancellation scanning. The device comprises a laser source, a polarization multiplexing double-parallel Mach-Zehnder modulator, an arbitrary waveform generator, an erbium-doped fiber amplifier, a polarization controller, a polarization beam splitter, a Mach-Zehnder interferometer, a photoelectric detector, an optical power meter, an electric power meter and a processing unit. The invention also provides a two-step measurement precision compensation photonics-assisted frequency measurement method. The method comprises the following steps of: firstly, quickly estimating a frequency band of an unknown radio frequency signal; and secondly, scanning and measuring in the estimated frequency band to obtain a precise frequency measurement result. According to the invention, high-precision and high-response-speed frequency measurement can be carried out by covering a large frequency monitoring range. In addition, high-resolution multi-frequency measurement can be further achieved, and the method is suitable for an integrated cognitive detection system in a complex electromagnetic environment.

The invention provides a broadband gain spectrum optimization method and device based on cascade Raman amplification assistance, and the method comprises the steps: receiving multiple paths of signal light, and carrying out the wavelength division multiplexing operation of the received multiple paths of signal light; respectively selecting signal light of a plurality of wave bands from the signals after the wavelength division multiplexing operation by utilizing a plurality of wavelength selection switches, wherein the plurality of wave bands comprise a plurality of wave bands between a C wave band and a U wave band; amplifying the signal light of the first group of wave bands in the selected signal light of the multiple wave bands through an erbium-doped fiber amplifier (EDFA) under the excitation of the pump light of the first wavelength, and amplifying the signal light of the second group of wave bands through a thulium-doped fiber amplifier (TDFA) under the excitation of the pump light of the second wavelength; amplifying the multiband signal light amplified by the EDFA or the TDFA by a plurality of cascaded backward RFAs respectively; and separating the multiple paths of signal light through wavelength division demultiplexing. The antenna has the advantages of being wide in broadband and high in gain, and enables a broadband gain spectrum to be flatter.

The invention discloses a blood alcohol testing device based on a 1.7 mu m waveband dual-wavelength laser light source, belongs to the technical field of laser detection and aims to solve a problem that an infrared spectrum alcohol concentration measuring device is low in measuring precision in the prior art. The device comprises a pump laser, an erbium-doped fiber amplifier, a fiber isolator, a first fiber circulator, a thulium-doped fiber, a photonic crystal fiber, a fiber coupler, a first collimator, test paper, a second collimator, a reflection grating, a detector, a data acquisition and processing module, a detection detector, an alarm device, a second fiber circulator, a switch, a first fiber bragg grating and a second fiber bragg grating. The device is advantaged in that dual-wavelength measurement is adopted, influence caused by other factors except the wavelength can be eliminated, measurement precision is improved, and the device uses an all-fiber device to generate 1.7 [mu]m waveband laser, and is compact in structure and high in stability, the equipment can be integrated into a small size, is convenient to carry and has wide application.

The invention belongs to the field of biomedical photonics, and particularly relates to a cell sorter based on inclined optical fiber grating optical tweezers. The cell sorter comprises a computer, alight source, an erbium-doped fiber amplifier, a modulator, a polarization controller, a micro-driver, a microscope, a micro-flow control chip and an inclined Bragg fiber grating, light emitted by thelight source is amplified in energy through the erbium-doped fiber amplifier, the light intensity is controlled through the modulator, then the light enters the inclined Bragg fiber grating through apolarization controller for filtering polarized light, the light forms a light trap through the inclined Bragg fiber grating, the micro-flow control chip is arranged at the light trap generation position, the microscope is used for observing the micro-flow control chip, and the computer is used for controlling the light source, the erbium-doped fiber amplifier, the modulator, the polarization controller and the micro-driver.

The invention discloses a photon multi-frequency doubling ultra-high radio frequency signal oscillator, which is suitable for the fields of optoelectronic technology, laser technology and optical communication. The device comprises a mode-locked laser (1), an optical isolator (2), an optical circulator (3), a phase-shifted chirped fiber grating (4), a 1*2 optical coupler (6), an optical polarization controller (7), an optical traveling wave phase modulator (8), a low-frequency signal amplifier (9), a low-frequency signal generator (10) and an optical band-stop filter (11), an erbium-doped fiber amplifier (12), an optical beam splitter (13), an optical spectrum analyzer (14) and a high-speed photodetector (15).

The invention relates to a fibre amplifier system (2, 2') for receiving and amplifying a laser pulse, for example an oscillator signal (SO) of an oscillator unit (3), comprises a fibre pre-amplifier system (5) based on a short, base-mode, in particular highly doped, stepped-index fibre (5C). The fibre amplifier system (2, 2') also has a main amplifier system (7) and, for example, at least one further pre-amplifier stage (5A) and a pulse selection unit (5B). The short, base-mode stepped-index fibre has a length which is less than or equal to 30 cm, and a mode field diameter which is greater than or equal to 30 [mu]m, e.g. a mode field diameter in the range from 30 [mu]m to 60 [mu]m, as well as a high doping concentration which is necessary to make available an absorption length less than orequal to 30 cm and has the purpose of providing a seed signal for the main amplifier system (7) without low linearity.

The invention discloses a radio frequency photon filter with a switchable pass-stop band, and is suitable for the field of radio frequency photons. The device comprises a device; a distributed feedback Bragg laser (1), a first light polarization controller (21), a second light polarization controller (22), an optical phase modulator (3), a 1*2 optical coupler (4), an optical isolator (5), a single-mode fiber (6), an optical circulator (7), a light intensity modulator (9), a radio-frequency signal generator (10), an erbium-doped fiber amplifier (11), an optical band pass filter (12), a photoelectric detector (13) and an optical network analyzer (14).

An erbium fiber laser produces a beam of ultrashort laser pulses having a center wavelength greater than 780 nanometers, an average power greater than 0.5 watt, and a pulse duration less than 200 femtoseconds. The fiber laser includes an erbium fiber amplifier that is energized by a pump beam having a pump wavelength longer than 1520 nanometers. The pump wavelength is selected to provide uniform gain over the broad spectral bandwidth of a seed beam and minimal gain at shorter wavelengths in the fiber amplifier, thereby overcoming gain narrowing and gain shifting. The pump beam has sufficient power to achieve pump saturation in the fiber amplifier.

The invention discloses a detection device for photon-assisted detection of weak radio frequency signals and a detection method thereof, and relates to the field of photoelectricity. The detection device comprises a semiconductor laser with a relaxation oscillation peak changing along with the change of bias current, output light of the semiconductor laser is amplified after passing through an erbium-doped fiber amplifier, the amplified output light is converted into an electric signal through a photoelectric detector, after the electric signal passes through a 5: 5 electric power divider, half of the signal is output to a frequency spectrograph for observation, and the other half signal is input to one input port of the 5: 5 coupler, the other input port of the 5: 5 coupler inputs a signal to be measured, and the signals and the signal to be measured are loaded to the semiconductor laser together, so that a photoelectric feedback loop is formed. A direct modulation mode is used, an external modulator and an optical filter are not used, the system cost is greatly reduced, the sensitivity of the system is higher, and the frequency tuning is flexible.