219 results about "Erbium doped fibre amplifier" patented technology

An apparatus, method and associated fiber-laser architectures for high-power pulsed operation and pumping wavelength-conversion devices. Some embodiments generate blue laser light by frequency quadrupling infrared (IR) light from Tm-doped gain fiber using non-linear wavelength conversion. Some embodiments use a fiber MOPA configuration to amplify a seed signal from a semiconductor laser or ring fiber laser. Some embodiments use the frequency-quadrupled blue light for underwater communications, imaging, and/or object and anomaly detection. Some embodiments amplitude modulate the IR seed signal to encode communication data sent to or from a submarine once the modulated light has its wavelength quartered. Other embodiments transmit blue-light pulses in a scanned pattern and detect scattered light to measure distances to objects in a raster-scanned underwater volume, which in turn are used to generate a data structure representing a three-dimensional rendition of the underwater scene being imaged for viewing by a person or for other software analysis.

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 distributed fiber sound wave detection apparatus and method based on wave beam formation. The apparatus comprises a light source, a 1*2 coupler, a control and signal processing unit, an arbitrary waveform generator, a double-channel parallel Mach-Zehnder electro-optical modulator, a reference arm fiber, an erbium doped fiber amplifier, an optical filter, an annular device, a front-end reflector, a reference length fiber, a rear-end reflector, a sense fiber, a 90-degree optical mixer, and a balance detector. The method includes the steps: injecting signal light into the sense fiber, the signal light being modulated to be light pulses with a fixed frequency on a lower side and a sweep frequency on an upper side; mixing the returned signal light carrying light phase information and light frequency spectrum information of detecting points with local reference light; demodulating the light phase information and the light frequency spectrum information, and obtaining the frequency, amplitude and phase information of sound waves in the detecting points in the sense fiber; and finally calculating the position, intensity and frequency information of sound sources. The sensing function and the transmission function of a fiber are combined into one function. Therefore, the distributed fiber sound wave detection apparatus and method have the advantages that the detecting point scale is hundred times higher than that of the prior art.

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 relates to a system for realizing network extension and protection functions with wave-division multiplexing annular optical access networks and a method for realizing the network extension and protection functions with the wave-division multiplexing annular optical access networks. The system is characterized in that an OLT (optical link terminal) is connected with M RNs (remote nodes) through an optical fiber to form an annular network, and the remote nodes are connected with ONUs (optical network units) through a distributed optical fiber, wherein the optical link terminal mainly comprises Q=Mq (1+n) optical transmitters, Q receivers, Mq transmitting C wave-band wavelength, Mnq transmitting L wave-band wavelength, Q 1X2 optical switches, three AWGs (arrayed waveguide gratings) of an identical structure and with Q ports, two EDFAs (erbium-doped fiber amplifiers), two optical circulators and a 2X1 coupler; and each remote node on a main ring mainly comprises a 2X2 optical switch, a 1X2 optical switch, two WBs (wavelength blockers), a CWDM (coarse wavelength division multiplexing), four common circulators, a closed circulator, six couplers and an arrayed waveguide grating. A feeder optical fiber is protected by the aid of use of the optical switches at the OLT end and designs of the annular structures and RN structures. By means of effective arrangement of the RN nodes, network scale extension can be realized, typical annular tangent topological structures are realized, network coverage area is greatly widened, and the quantity of users is greatly increased. The system realizes dynamic dispatching of the wavelength by adjusting the wavelength blockers and changing operating ports of the arrayed waveguide gratings, and achieves balance between the cost and the performance.

A system includes an optical transmitter that outputs an optical signal having a substantially Gaussian waveform and an optical receiver that is optically coupled to the optical transmitter and has an impulse response essentially matching the waveform. The impulse response and waveform preferably match in the time domain. The transmitter and receiver may be average-power-limited, using, for example, an erbium-doped fiber amplifier. To achieve a high signal-to-noise ratio, the waveform may be designed to minimize jitter, sample duration, matching parasitics, and inter-symbol interference (ISI). Such a waveform may be a return-to-zero (RZ) Gaussian or Gaussian-like waveform and may be transmitted in a variety of modulation formats. Further, the system may be used in WDM or TDM systems. A method for characterizing the time domain impulse response of an optical element used in the optical receiver is provided, where the method is optionally optimized using deconvolution and/or cross-correlation techniques.

The invention discloses a microwave photon up-conversion device and method based on a photoelectric oscillator and belongs to the technical field of microwave photonics. The device is composed of a laser source, a first coupler, a first circulator, a first high nonlinearity dispersion displacement optical fiber, an erbium-doped optical fiber amplifier, a first photoelectric detector, a second coupler, a first Mach-Zehnder modulator, a first microwave signal source, a first direct current voltage-stabilized power supply, an optical filter, a second Mach-Zehnder modulator, a second direct current voltage-stabilized power supply, a second circular, a second high nonlinearity dispersion displacement optical fiber, a second photoelectric detector, a microwave amplifier, a double-parallel Mach-Zehnder modulator, a third direct current voltage-stabilized power supply, a fourth direct current voltage-stabilized power supply, a fifth direct current voltage-stabilized power supply, an optical isolator and a spectrum analyzer. A Brillouin frequency shift value f of the high nonlinearity optical fiber is 9.2GHz, and a signal with frequency of f<m> can be up converted to f<m>+18.4GHz, so alow quality and low frequency intermediate signal is converted into a high quality and high frequency signal.