450 results about "Optical fibre amplifiers" patented technology

The inventive optical fiber coupler array is capable of providing a low loss, high-coupling coefficient interface with high accuracy and easy alignment between a plurality of optical fibers (or other optical devices) with a first channel-to-channel spacing, and an optical device having a plurality of closely-spaced waveguide interfaces with a second channel-to-channel spacing, where each end of the optical fiber coupler array is configurable to have different channel-to-channel spacing, each matched to a corresponding one of the first and second channel-to-channel spacing. The novel optical coupler array includes a plurality of waveguides (at least one of which may optionally be polarization maintaining), that comprises at least one gradually reduced vanishing core fiber, at least in part embedded within a common housing structure. Alternatively, the novel coupler array may be configured for utilization with at least one of an optical fiber amplifier and an optical fiber laser.

The present invention relates to an optical component comprising an acceptance fibre, e.g. a photonic crystal fibre, for propagation of pump and signal light, a number of pump delivery fibres and a reflector element that reflects pump light from the pump delivery fibres into the acceptance fibre. It is an object of the invention to provide a fibre coupler for coupling two or more light sources into a multi-clad (e.g. double clad) optical fibre, which has practical advantages with respect to handling, loss and back reflection. An object of the invention is achieved by an optical component comprising a) a first fibre having a pump core with an NA1, and a first fibre end; b) a number of second fibres surrounding said pump core of said first fibre, at least one of said second fibres has a pump core with an NA2 that is smaller than NA1, said number of second fibres each having a second fibre end; and c) a reflector element comprising an end-facet with a predetermined profile for reflecting light from at least one of said second fibre ends into the pump core of said first fibre. The invention further relates to articles comprising the optical component (e.g. a laser or amplifier), to methods of its production and use. The invention further relates to a rod-type optical fibre with optimized stiffness to volume ratio. The invention may e.g. be useful in applications such as fibre lasers or amplifiers, where light can be coupled efficiently from pump sources to an acceptance fibre, e.g. a double clad fibre, using the optical component. The invention specifically addresses optical fibre amplifiers where pump light and signal light are propagating in different directions (counter-propagating pump) within a double-clad optical fibre.

The invention discloses a novel method for realizing spectral combination amplification based on the frequency division multiplexing technology, which comprises the following steps of: (a), pre-amplifying and broadening laser pulse generated by an ultra-short pulse oscillator; (b), segmenting the frequency spectrum of a super-continuous broad-band spectrum into multiplex optical pulses with different central wavelengths; (c), amplifying each optical pulse, outputting a part of amplified seed light to a self-reference zero-frequency detection device by using a splitting slice, and taking a beat frequency signal output by the self-reference zero-frequency detection device as the driving frequency of an acousto-optic frequency shifter after filtering and amplifying; (d), coherently synthesizing amplification pulses output by various multi-stage optical fibre amplifiers through a wavelength division multiplexing beam combiner; and (e), carrying out dispersion compensation and pulse width compression of coherently synthesized pulses by using a compressor so as to obtain ultra-short pulse output with high peak power. According to the invention, the frequency division multiplexing technology and the coherent synthesizing technology are organically combined; therefore, the pulse synchronization problem and the spectrum coherent problem in the ultra-short pulse optical fibre laser coherent synthesizing process are solved.

The invention relates to the technical field of fiber sensing, and especially to a pre-pumped pulse and Gray code based BOTDA instrument. The BOTDA instrument comprises a narrow-linewidth semiconductor sensor, a coupler, a first erbium doped fiber amplifier, a first polarization controller, a single sideband modulator, a microwave source, an optical isolator, a sensing fiber, an optical annular device, a second erbium doped fiber amplifier, a polarization scrambler, an electro-optical intensity modulator, a second polarization controller, an arbitrary waveform generator, an optical filter, a photoelectric detector and a signal collecting and processing system. On the premise that the high spatial resolution of a BOTDA system is maintained, the BOTDA instrument ensures the sensing distance and the measuring precision of the system, and improves the sensing performance of the system.

The invention discloses a high-speed demodulation method for a high-capacity weak grating sensing network. The method comprises the following steps: (1) inscribing a plurality of weak gratings FBGr, FBG1, FBG2, FBG3 and the like in sequence on an optical fiber, wherein the FBGr is taken as a reference grating, and the FBG1, FBG2, FBG3 and the like are divided into m (m is more than or equal to 1) groups of identical weak grating arrays for constructing a sensing network; (2) generating pulse light by using a pulse laser, introducing the pulse light into the reference grating and the sensing network through an optical circulator, returning the reflected signal of each weak grating to the optical circulator, and introducing the reflected signals into an erbium-doped optical fiber amplifier for amplifying; (3) feeding the amplified reflected signals into a dispersion compensation optical fiber, receiving the time of the reflected signal of each weak grating by using a photoelectric detector, and performing signal processing through a high-speed data acquisition system to obtain the wavelength change of each weak grating in the sensing network in order to realize demodulation. A high-speed demodulation device for the high-capacity weak grating sensing network mainly comprises a pulse laser, an optical circulator, an optical fiber inscribed with a plurality of weak grating, am erbium-doped optical fiber amplifier, a dispersion compensation optical fiber, a photoelectric detector and a high-speed data acquisition system.

The invention discloses an all-optical wavelength converting device based on non-linear optical waveguide. The device comprises a first optical coupler, an erbium-doped optical fiber amplifier, a polarization controller, a PPLN waveguide, an optical isolator, a second optical coupler and a pump optical wavelength selector, which are connected in sequence by optical paths in clockwise direction to form an annular cavity laser with the built-in PPLN optical waveguide. The first optical coupler and the second optical coupler respectively provide a signal light input port and a converted idle light output port for the external. The non-linear optical waveguide is the PPLN optical waveguide and the pump optical wavelength selector is a dual wavelength selector or a multiple wavelength selector. The pump light produced by signal light and the inner of the annular cavity by lasing carries out non-linear mutual interaction in the PPLN optical waveguide to generate converted idle light, so as to realize wavelength converting. The device can realize tunable wavelength converting of single-channel to dual-channel and single-channel to multi-channel (broadcasting type) and input and output tunable wavelength converting with the advantages of flexible converting function, compact and easily realizable structure and low cost.

A fiber amplifier having two erbium doped fiber coils and a pump laser diode optically coupled, through a fiber array, to a planar lightwave circuit, is described. A photodetector array, a multiport free-space optical isolator, and a strip of thin-film gain flattening filter are attached to a side surface of the planar lightwave circuit, which has a tunable optical power splitter for variably splitting the optical pump power for the laser diode between the two erbium doped fiber coils, and variable tilters for correcting the gain tilt of the amplifier. The variable splitter and the tilters are thermally tunable Mach-Zehnder interferometers.

The invention discloses a microwave photonic zero-intermediate-frequency receiving device and method. The method relates to the technical field of microwave and the technical field of optical communication. The method is as shown in the drawings. The device comprises a laser (LD), a polarization multiplexing Mach-Zehnder modulator (PDM-MZM), an erbium-doped optical fibre amplifier (EDFA), a wavelength division multiplexer (WDM), polarization controllers (PCs), a polarization beam splitter (PBS) and balance photoelectric detectors (BPDs). Modulation and polarization multiplexing of radio-frequency (RF) and local oscillator (LO) signals are carried out by utilization of the PDM-MZM; the WDM separates upper and lower optical sidebands; the PCs are respectively utilized for adjusting the polarization states of optical signals; and finally, the two BPDs respectively output I-channel and Q-channel baseband signals. By means of the microwave photonic zero-intermediate-frequency receiving device and method disclosed by the invention, zero-intermediate-frequency receiving is realized through a photonic method; the electronic bottleneck in the traditional electric field technology can be overcome; and the microwave photonic zero-intermediate-frequency receiving device has the advantages of being wide in working band, high in IQ balance degree, inhibited in direct-current offset and even-order distortion, electromagnetic-interference-resistant and the like.

The invention discloses a producing method which is easily implemented and can output stable single-longitudinal-mode multi-wavelength broadband-tunable brillouin laser, and a brillouin laser device. The method uses the brillouin laser device which is composed of an optical passive resonant cavity and an erbium-doped fiber amplifier arranged at the outer part of the optical passive resonant cavity, brillouin stokes light generated in the optical resonant cavity is fed back to the erbium-doped fiber amplifier, and therefore the single-longitudinal-mode multi-wavelength broadband-tunable brillouin laser is obtained. The brillouin laser device comprises the erbium-doped fiber amplifier, a tunable laser device and the optical passive resonant cavity, wherein the erbium-doped fiber amplifier is arranged at the outer part of the optical passive resonant cavity; the tunable laser device is connected with the erbium-doped fiber amplifier through a fiber coupler; and the optical passive resonant cavity is connected with the output end of the erbium-doped fiber amplifier. Meanwhile, the optical passive resonant cavity is connected with the input end of the erbium-doped fiber amplifier through the fiber coupler.

The invention relates to a filter feedback reusable millimeter wave subcarrier light controlled microwave beam forming network, which belongs to the technical field of millimeter wave subcarrier optical controlled microwave beam forming, and is characterized in that a wavelength selecting reusable module transforms wide-spectrum light output by wide-spectrum light source to a comb-like spectrum; the comb-like spectrum is modulated by microwave signals which need to be transmitted, and the comb-like spectrum most energy of which is concentrated in the peak wavelength is formed after dispersive delay and amplification; then an adjustable filter in the wavelength selecting reusable module is utilized for inverse filtering to obtain each required signal; amplification efficiency of an erbium-doped optical fibre amplifier is greatly enhanced, and then the power level of useful spectra of the entire link is enhanced; and compared with that traditional wide-spectrum light passes through the light controlled microwave beam forming network, the invention enhances energy utilization.

The invention relates to s double-clad optical fiber comprising a fiber core and a cladding. The optical fiber is characterized in that the fiber core is a silica-base glass core layer doped with ions, the cladding comprises an inner cladding body and an outer cladding body, the inner cladding body is a total solid silica-base glass layer composed of two doping stress areas with the low refractive index, the doping stress areas are symmetrical about the fiber core, the outer cladding body is an annular silica-base glass layer formed by air holes, the outer cladding body is provided with a supporting layer, the supporting layer is a total solid silica-base glass layer, and the outermost layer of the optical fiber is a coating layer. Special coating with the lower refractive index is needless to serve as the outer cladding body, so that coating cost is greatly reduced. The outer cladding body is silica-base glass with air holes, and is resistant to high temperature, safe, suitable for being used in a high-power optical cable laser and an optical fiber amplifier, and meanwhile suitable for optical fiber preparation in a large mode field area. The double-clad optical fiber has the advantages of being high in birefringence rate, keeping linear polarization, being large in mode filed area and the like.

The present invention mainly utilizes the spontaneous raidation noise of backward pump, i.e. light power level of ASE to implement autoamtic control of Raman gain of Raman optical-fibre amplifier andcompensation. Its Raman optical-fibre amplifier is characterized by that at the signal light detection place a combination of filter and photoelectric detector for detecting the backward ASE power ofRaman optical fibre amplifier nearby dirrerent wavelength is added, the output of the photoelectric detector is connected with control unit of automatic regulation of gain of Raman amplifier.

The invention relates to an optical fiber beam combiner and a preparation method thereof, and the technical problem that reverse isolation performance for protection of a pump laser is poor is solved. The optical fiber beam combiner is composed of an input multimode fiber, an input signal optical fiber and an output optical fiber. After fused biconical tapering is carried out on a bare fiber of the input multimode fiber and a bare fiber of the input signal optical fiber to some extent, the bare fiber of the input multimode fiber and the bare fiber of the input signal optical fiber are perpendicularly cut from the middle to be connected with a bare fiber of the output optical fiber in a fused mode. The input signal optical fiber is an optical fiber having a cladding is formed by random optical fibers with claddings in a fused connection mode. The optical fiber beam combiner of the structure has excellent reverse isolation performance, well protects the pump laser, is especially applied to a high-power fiber laser and an optical fiber amplifier, and has the advantages of being simple in manufacturing process, high in coupling efficiency, stable in performance and the like.

The invention is light-path mixer in optical communication field, in which wave-division multiplexer, optical isolator and spectral coupler are integrated, used in fibre-optical amplifier. In light-path direction, it in turn includes the first double fiber-optical ocillator whose output end face is pasted with WDM filtering piece, wedge-shape isolator composed of two double-fraction crystal wedgepieces and one Faraday rotation crystal, hexagon-section spectral prism and the second double fibre-optical collimator; and the wedge-shape isolator and the spectral prism can be clamped between two glass pieces and together placed in permangnet magnetic ring.

An amplifier includes two parts as Raman amplifying part consists of a set of pumping laser array, pumping wave combining device, a section of Raman gain optical fibre, signal/pumping multiplexer and demultiplexer and signal demultiplexer; gain feedback control device consists of signal input-output power measurement and pumping laser controller. As discrete Raman optical fibre amplifier, it can realize C+L waveband 1428-1604 nm dispersion compensation by applying dispersion compensating fibre as Raman gain media and realize gain spectrum smooth and fluctuation control for optical signal waveband by controlling output power of N number of pumping lasers in 14xxnm.

The invention relates to an optical fiber liquid level measurement device and an optical fiber liquid level measurement method and belongs to the technical field of optics. The invention aims at solving the problems that an existing optical liquid level sensor is complex in manufacturing process, low in measurement accuracy, small in measurement range and unstable in device structure. The optical fiber liquid level measurement device comprises a laser, an optical fiber coupler, a polarization controller, an electrooptical modulator, an erbium-doped optical fiber amplifier, a microwave source, an arbitrary-function generator, a circulator, an optical fiber Bragg grating, an optical isolator, a sensing optical fiber, a self-heating type optical fiber, a photoelectric detector, a data acquisition card and a power meter. The optical fiber liquid level measurement method comprises the following steps: combining a Brillouin optical-time domain analysis technology with the self-heating type optical fiber, wherein the self-heating type optical fiber converts optical energy into heat energy and is pasted with the sensing optical fiber together to realize thermal transmission; and immersing a sensing part into liquid, judging the position where the liquid level is located by virtue of a temperature abrupt change point, thereby realizing centimeter magnitude resolution, meanwhile, measurement range is tens of centimeters, so that high-resolution and high-accuracy liquid level measurement is realized.

The invention discloses an optical fiber distributed vibration sensing system and a phase discrimination nonlinear error correction method, which relate to the technical field of signal processing. The optical fiber distributed vibration sensing system includes a continuous laser source, a first coupler, an acousto-optic modulator, an optical fiber amplifier, a circulator, an optical fiber coupler, a balance detector, an analog phase discrimination circuit module, a control display terminal and an acousto-optic modulator driver which are connected in series. The optical fiber distributed vibration sensing system further includes a signal generator connected with the analog phase discrimination circuit module. The acousto-optic modulator driver is connected with the acousto-optic modulator. The output end of the first coupler is connected with the acousto-optic modulator and the optical fiber coupler. One output end of the circulator is connected with the optical fiber coupler, and the other output end is connected with a sensing optical fiber and a piezoelectric ceramic in turn. The analog phase discrimination circuit module is a dual-path reference phase discrimination circuit. The problems solved in the invention are as follows: (1) required digital signal detecting and processing equipment with high performance costs high; (2) the traditional digital phase discrimination process using DCM and inverse tangent is complicated.

The present invention is to provide an optical fiber amplifier for clamping and equalizing gain in optical communication systems comprising: a gain clamping amplifier unit for clamping the gain, so as to make input signals have the same output power for each channel by applying a compensating signal; a second isolator for passing the input signal light from said gain clamping amplifier unit and isolating the light coming from the opposite direction; a gain equalizing filter for equalizing the output gain spectrum from the input signal from said second isolator; and a post-amplifier unit for amplifying the signal from said gain equalizing filter. Thus, the optical fiber amplifier is capable of clamping gain automatically by maintaining the same population inversion, and capable of maintaining the same gain equalization for the wide signal gain band to achieve the high transmission capacity, in cases that the number of channel varies in the input signal, while providing a high output signal power.

The invention discloses a method and a device for generating a high-precision optical fiber optical comb seed pulse through full-optical difference frequency. The method is integrated with the processes of optical fiber ultrashort pulse generation, high-power optical fiber amplification, optical fiber non-linear frequency mixing, optical difference frequency and frequency doubling and the like; the device comprises a laser oscillator, a six-wave mixing amplifier, an optical comb difference frequency device and an optical comb frequency doubling device. Laser pulse finally output by the device is extremely close to system initial seed light frequency, and the carrier envelope phase is stable, so that the device can be directly taken as a seed optical comb of an optical fiber amplifier of a wave band corresponding to signal light. Two signal light required in the difference frequency process comes from the same non-linear mixing process, so that the phase noise of the signal light generated during the difference frequency can be automatically eliminated, and optical comb laser with high pulse strength and high contrast ratio, in which the infrared band carrier envelope phase is zero, is obtained.

The present invention discloses a Fiber Bragg Grating demodulation device with a suppressed fluctuation at a variable ambient temperature and a demodulation method. The device comprises a broadband light source (1), an optical attenuator (2), a tunable F-P filter (3), a first optical fiber isolator (41), an erbium-doped optical fiber amplifier (5), an optical fiber first-stage beam splitter (6), a first optical fiber second-stage beam splitter (71), optical fiber circulators (8), FBG sensor arrays (9), a first photoelectric detector array (161), an optical fiber gas cell (10), a second optical fiber second-stage beam splitter (72), an optical fiber F-P etalon (11), a notch filter (12), an optical fiber assisted interferometer (13), a data acquisition card (17) and a processor (18).