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354 results about "Erbium doped fiber amplifier" patented technology

How EDFA (Erbium Doped Fiber Amplifier) Works. When a normal optical fiber core is doped with trivalent ‘erbium’ ions, erbium doped fiber is formed. This erbium doped fiber act as a gain medium that amplifies an optical signal. Hence, it is named as EDFA (Erbium Doped Fiber Amplifier).

Automatic raman gain and tilt control for ultra-long-distance dense WDM optical communication system

An approach for automatic Raman gain and tilt control for a WDM (Wavelength Division Multiplexing) optical communication systems is disclosed. An optical fiber carries a plurality of optical signals, in which at least one of the optical signals are reference signals. An optical gain unit (e.g., Raman pump unit) couples to the optical fiber and adjusts the reference signals to compensate, in part, for losses associated with the optical fiber and gain tilt accumulation. Upon detecting and analyzing the reference signals, a controller controls the optical gain unit and outputs a control signal to the optical gain unit based upon the analyzed reference signals. An optical amplifier is connected to the optical fiber and amplifies the optical signals. The optical gain unit provides a nearly constant power per channel at an input of the optical amplifier. Under this approach, a Raman gain control mechanism, combined with the use of gain controlled EDFA (Erbium Doped Fiber Amplifier), allows high transmission capacity over ultra-long distances without optical regeneration and with high flexibility.
Owner:CISCO TECH INC

Distributed optical fiber sensor based on roman and brillouin scattering

A distributed optical fiber sensor based on Raman and Brillouin scattering is provided. The distributed optical fiber sensor includes a semiconductor FP cavity pulsed wideband optical fiber laser (11), a semiconductor external-cavity continuous narrowband optical fiber laser (12), a wave separator (13), an electro-optic modulator (14), an isolator (15), an Er-doped optical fiber amplifier (16), a bidirectional coupler (17), an integrated wavelength division multiplexer (19), a first photoelectric receiving and amplifying module (20), a second photoelectric receiving and amplifying module (21), a direct detection system (22), a narrowband optical fiber transmission grating (23), a circulator (24) and a coherence detection module (25). The temperature and the strain can be measured simultaneously, and the signal-to-noise ratio of the system is enhanced.
Owner:CHINA JILIANG UNIV

Retrofit heater for erbium fiber in an erbium-doped fiber amplifier (EDFA)

A heater system for heating an erbium-doped fiber amplifier (EDFA) of a fiber optic communication system operable in an environment. The heater system includes a pump laser for providing optical power to an erbium fiber in the EDFA. The pump laser is cooled by a thermoelectric cooler (TEC) when a predetermined maximum temperature is reached to maintain the temperature of the laser below the maximum temperature value. The temperature of the laser is sensed by a temperature sensor and is conveyed to a control circuit for generating a control signal. A heater unit is thermally connected to the erbium fiber and is controlled by the control signal in the event that the sensed temperature falls below a predetermined minimum value to maintain the temperature of the fiber above the minimum temperature value. A switch is connected between the control circuit, the TEC and the heater to automatically direct current to either the heater or the TEC depending on the sensed temperature.
Owner:AGERE SYST INC

Distributed ultrahigh-speed disturbance quantitative detection method and device

ActiveCN106248119AHigh repetition rateUltra-high-speed disturbance detectionConverting sensor output opticallyGratingBand-pass filter
The invention discloses a distributed ultrahigh-speed disturbance quantitative detection method. Ultrahigh-speed disturbance detection can be realized through a time division multiplexing method; and phase demodulation is carried out through phase demodulation methods such as Hilbert transformation and orthogonal transformation so as to be able to realize real-time detection on the disturbance position, frequency and amplitude. The invention further discloses a distributed ultrahigh-speed disturbance quantitative detection device, which comprises a pulse generator, a laser, a first coupler, a pulse modulator, an erbium-doped optical fiber amplifier, a circulator, an optical fiber sensing unit, a second coupler, a balance detector, a band-pass filter, a power amplifier and a data acquisition card. According to the invention, the repetition frequency of detecting light pulses is improved through a time division multiplexing technology, so that a reflecting grating based phi-OTDR system is enabled to realize ultrahigh-speed disturbance detection; and real-time detection for the disturbance position, frequency and amplitude is realized through the phase demodulation method by using a coherent detection structure and combining a phase unwrapping algorithm.
Owner:NANJING UNIV

Serial-parallel connection modulation optical frequency multiplication millimeter-wave RoF (Radio Over Fiber) system and QPSK (Quadrature Phase Shift Keying) /16QAM (Quadrature Amplitude Modulation) modulation method thereof

The invention relates to a serial-parallel connection modulation optical frequency multiplication millimeter-wave RoF (Radio Over Fiber) system and a QPSK (Quadrature Phase Shift Keying) / 16QAM (Quadrature Amplitude Modulation) modulation method thereof. The system comprises a central station, a base station and fiber connection thereof, wherein the central station comprises a single longitudinal mode laser, a double-electrode Mach-Zehnder optical modulator, an IQ optical modulator, two microwave signal sources, a pi phase shifter, a pi / 2 phase shifter and an erbium doped fiber amplifier; and the base station comprises an optical detector, a front low-noise amplifier, two millimeter-wave bandpass filters, two millimeter-wave amplifiers, a millimeter-wave duplexer and a millimeter-wave antenna. In the method, the cascading of the double-electrode Mach-Zehnder optical modulator and the IQ optical modulator is adopted, and a balanced optical waveguide structure formed by integrating the two optical modulators avoids the influence of optical source phase interference noise caused by support arm optical delay inequality on modulation signals.
Owner:SHANGHAI UNIV

High power semiconductor laser with a large optical superlattice waveguide

The invention relates to high power semiconductor diode lasers of the type commonly used in opto-electronics, mostly as so-called pump lasers for fiber amplifiers in the field of optical communication, e.g. for an erbium-doped fiber amplifier (EDFA) or a Raman amplifier. Such a laser, having a single cavity and working in single transverse mode, is improved by placing a multilayer large optical superlattice structure (LOSL) into at least one of the provided cladding layers. This LOSL provides for a significantly improved shape of the exit beam allowing an efficient high power coupling into the fiber of an opto-electronic network.
Owner:LUMENTUM TECH UK LTD +1

Distributed Raman amplification-based Brillouin optical time domain analysis system

The invention discloses a bidirectional distributed Raman amplification-based Brillouin optical time domain analysis system. The system comprises a laser 1, a coupler 3, a first electro-optical modulator 6, a second electro-optical modulator 17, a polarization scrambler 8, a first erbium-doped fiber amplifier 9, a second erbium-doped fiber amplifier 18, an optical circulator 12, a tunable filter 11, a detector 10, a data acquisition processing system 7 and a Raman amplification system. In the system, the bidirectional distributed Raman amplification technology is applied in the Brillouin optical time domain analysis system to improve the distribution evenness of Brillouin detection signal gain on a whole section of a sensing fiber, so that the temperature / strain resolution of the whole section of the sensing fiber can be ensured, and long distance distribution sensing in true sense can be realized.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA

Contact type temperature non-inductive three-dimensional detection sensor based on fiber Bragg grating (FBG)

InactiveCN102589439ACapable of 3D detectionRealize three-dimensional space position signal detectionUsing optical meansFiberGrating
The invention discloses a contact type temperature non-inductive three-dimensional detection sensor based on a fiber Bragg grating (FBG) and belongs to the technical field of precision instrument manufacturing and precision test measurement. The sensor comprises a broadband light source system which consists of a pump laser, a wavelength division multiplexing (WDM) coupler, an erbium-doped fiber and a beam splitter, a temperature compensation system which consists of an erbium-doped fiber amplifier (EDFA), a first circulator, a guide pipe, a reference FBG and a fiber barrier, a probe, and a signal receiving system which consists of an optical spectrum analyzer, a fiber coupler and an index-matching fluid, wherein the reference FBG of the temperature compensation system is arranged in a spatial distance of 30 cm of the probe. By the sensor, three-dimensional sensing is realized, and the environmental adaptability of the sensor is greatly improved. The sensor has the characteristics of simple structure and high real-time performance and is easy to practically use. The sensor has the advantage of quick and ultra-precise measurement and calibration of small cavity size.
Owner:HARBIN INST OF TECH

Microwave photon mixing method and system based on local oscillator frequency doubling

The invention discloses a microwave photon mixing method and system based on local oscillator frequency doubling, and belongs to the fields of optical communication and microwave photonics. The microwave photon mixing system based on local oscillator frequency doubling is formed by utilizing a double-polarization double-parallel mach-zehnder modulator through combination with devices such as a laser, a front polarization controller, a microwave 90-degree coupler, a rear polarization controller, an optical fiber polarizer, an adjustable optical band-pass filter, an erbium-doped fiber amplifier,a photoelectric detector and the like. The system adopts second-order local oscillator sideband and first-order radio frequency sideband beat frequencies, and mixing processing based on local oscillator frequency doubling can be realized; on one hand, the frequency requirement of a mixing system on a local oscillator signal is reduced, and on the other hand, due to the fact that a single-sidebandmodulation mode is adopted, stray signals can be effectively reduced. In addition, the mixing method can realize switching of up conversion and down conversion by changing a direct current bias voltage, and can be used for time-sharing transmitting and receiving of radio frequency.
Owner:BEIJING UNIV OF TECH

Methods and apparatus for upgrading passive optical networks

An optical network system can be used to update legacy passive optical networks by adding an optical transmitter, blocking filter, and / or pluggable or unpluggable optics. In one embodiment, an optical network system, including several optical transmitters and receivers, multiplexers, demultiplexers, erbium-doped fiber amplifier, and blocking filter, may be employed. The additional transmitter increases available bandwidth, while the blocking filter allows existing customers' service(s) to not be impacted. Another embodiment uses pluggable or unpluggable optics, instead of the aforementioned blocking filter, to receive and modulate optical signals to transmit services to end users. In one embodiment, an optical network system can be employed that allows for simultaneous upgrading of the system and providing of legacy services, while allowing for the of removal existing optical network components over time.
Owner:TELLABS BEDFORD

Real-time scattering type terahertz quasi-time-domain near field polarization spectrograph

A real-time scattering type terahertz quasi-time-domain near field polarization spectrograph comprises a multimode laser module, an erbium-doped fiber amplifier, an optical fiber beam splitter, a photoconduction transmitting antenna, a polarization module, a focusing lens A, an atomic force microscope, a focusing lens B, an optical fiber extension module, a photoconduction receiving antenna and a phase-locked amplifier. The multimode laser module emits a multimode laser, the multimode laser passes through the erbium-doped fiber amplifier and is split into a pumping light beam and a detection light beam, the pumping light beam stimulates the photoconduction transmitting antenna module to radiate a quasi-time-domain terahertz signal, the terahertz signal is transmitted to an oscillating probe tip of the atomic force microscope, the detection light beam enters the photoconduction receiving antenna, and finally the signal is extracted and amplified through the phase-locked amplifier. The spectrograph has the advantages of being low in cost, small in size and not prone to hurting eyes, having the real-time performance, and the like, and can be widely applied to the field of super-resolution detection on terahertz signals in scientific research and industry.
Owner:CHONGQING INST OF GREEN & INTELLIGENT TECH CHINESE ACADEMY OF SCI

Pre-pumped pulse and Gray code based BOTDA (Brillouin Optical Time Domain Analysis) instrument

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.
Owner:NAT UNIV OF DEFENSE TECH

All-optical true random number generator with Tbps-level code rate

An all-optical true random number generator with a Tbps code rate comprises an all-optical true random number entropy source and an all-optical quantizer, wherein the all-optical true random number entropy source adopts an rational harmonic mode-locked Er-doped fiber ring laser, actually a ring-shaped cavity formed by a lithium niobate electro-optic modulator, an optical band pass filter I, an erbium-doped fiber amplifier, an opto-isolator and an optical coupler which are connected through fiber; and the all-optical quantizer is a quantum dot quarter wave phase-shift distributed feedback type laser. The generator provided by the invention solves the problems that the code rate is too low and untunable in the prior art, has a Tbps-level code rate, is in direct compatible with an optical network, and meets the safety requirements of modern high-speed secure communication.
Owner:TAIYUAN UNIV OF TECH

Backscattering enhanced fiber distribution type temperature and strain dual-parameter sensing device and demodulation method thereof

The invention discloses a backscattering enhanced fiber distribution type temperature and strain dual-parameter sensing device and a demodulation method thereof. The sensing device is composed of a narrow-linewidth light source, a coupler, an acousto-optic modulation module, a driver, an erbium-doped fiber amplifier, a circulator, a Raman wavelength division multiplexer, a sensing fiber having a plurality of continuous scattering enhanced point, a filter device, a photoelectric detector, a data acquisition card, and an upper computer. The implementation principle of dual-parameter measurementis as follows: on the basis of the sensitivity to the external environment change by a phase of a backscattering Rayleigh light signal in a sensing fiber and sensitivity to a temperature change by a Raman scattered light intensity, an implementation scheme of absolute temperature stress distributed measurement is provided by using an optical time domain reflection technology, a coherent detectiontechnology, a beat frequency signal cross correlation technology, a phase demodulation technology, a wavelength division multiplexing technique, and a temperature stress decoupling technique. Therefore, simultaneous measurement of a temperature field and a stress field continuously distributed along the optical fiber is realized. Moreover, the measuring distance is long; the spatial resolution ishigh; the sensitivity is high; the response speed is fast; and the error is small.
Owner:HUAZHONG UNIV OF SCI & TECH

Hybrid optical fiber amplifier as well as method and device for adjusting gain and gain slope of amplifier

The invention is suitable for the technical field of optical communication and provides a hybrid optical fiber amplifier as well as a method and device for adjusting the gain and the gain slope of the amplifier. The hybrid optical fiber amplifier comprises an RFA (Raman fiber amplifier) and an EDFA (erbium doped fiber amplifier), wherein the EDFA excludes a variable attenuator; the RFA comprises a pump signal multiplexer, a pump laser group, an out-of-band narrow-band filter and a photoelectric detector; the EDFA comprises an input coupler, an erbium doped fiber, an output coupler, an input photoelectric detector and an output photoelectric detector, all of which are connected in sequence; and the hybrid optical fiber amplifier further comprises a control module for controlling the RFA and / or EDFA to adjust the gain and / or the gain slope according to an excepted amplification requirement. Due to the fact that the RFA and the EDFA are controlled and coordinated by the control module according to the technical scheme, an excepted amplification effect can be achieved; in addition, a series of problems caused by the variable attenuator can be avoided due to the fact that the EDFA excludes the variable attenuator.
Owner:GUANGXUN SCI & TECH WUHAN

Sensing device based on Raman-Brillouin distributed temperature and stress dual-parameter detection

ActiveCN106248247AAccurate and simultaneous acquisition of temperature and stress dual parametersForce measurement by measuring optical property variationThermometers using physical/chemical changesSpectrum analyzerBand-pass filter
The invention discloses a sensing device based on Raman-Brillouin distributed temperature and stress dual-parameter detection. The sensing device is composed of a laser, a first coupler, a polarization controller, a pulse generator, a semiconductor optical amplifier, an erbium-doped fiber amplifier, a band-pass filter, a second coupler, an optical attenuator, a first circulator, a third coupler, a multi-core fiber, a second circulator, a Raman filter, a first d photoelectric detector, a second photoelectric detector, an oscilloscope, a polarization controller, a modulator, a microwave generator, a polarization switch, a fourth coupler, a third photoelectric detector, a power spectrum analyzer and a data processing module. Because a spatial-division multiplexing system is formed by using a single-mode multi-core fiber, a problem of mode coupling of a mode -division multiplexing system and power mismatching of a wavelength-division multiplexing system can be solved and thus an effect of precise and simultaneous temperate and stress obtaining can be realized.
Owner:HUAZHONG UNIV OF SCI & TECH

Raman optical fiber amplifier and detection method of loss of transmission optical fiber connector of Raman optical fiber amplifier

ActiveCN102749783ANot affectedKnow the relative insertion loss in real timeLaser detailsTesting optical propertiesErbium dopingFiber amplifier
The invention relates to a Raman optical fiber amplifier and a detection method of loss of a transmission optical fiber connector of the Raman optical fiber amplifier. A transmission end (with a pumping signal multiplexer) of the amplifier is connected with a public end (with an out-of-band ASE (amplification of spontaneous emission) optical filter) of the amplifier, an out-of-band ASE output end of the out-of-band ASE optical filter is connected with a photoelectric detector, an output end of the photoelectric detector is connected with an input end of a control unit, an output end of the control unit is connected with an input end of a pumping laser device group, the pumping laser device group is connected with a pumping end of the pumping signal multiplexer, and a public end of the pumping signal multiplexer is connected with an input end of an erbium-doped fiber amplifier through a transmission optical fiber. The detection method comprises the following steps of: outputting a group of pumping light with determined power; determining a mathematic relation of out-of-band ASE optical power and pumping light power, and determining a mathematic relation of joint loss and the out-of-band ASE optical power; and determining a loss value of a joint. According to the Raman optical fiber amplifier and the detection method of the loss of the transmission optical fiber connector of the Raman optical fiber amplifier, disclosed by the invention, the gain and the gradient of the gain can be exactly controlled, the relative insertion loss of a transmission optical fiber line is known in real time, and performances of products can be improved.
Owner:GUANGXUN SCI & TECH WUHAN

Microwave signal photonic frequency conversion and multichannel fiber transmission device and method

The invention discloses a microwave signal photonic frequency conversion and multichannel fiber transmission device and method realized by a polarization multiplexing modulator. The device, as shown by a figure, comprises a laser diode (LD), a polarization multiplexing Mach-Zehnder modulator (PDM-MZM), an erbium doped fiber amplifier (EDFA), a 1:N light splitter (Splitter), a polarizer (Pol), a polarization controller (PC), and a standard single-mode fiber (SMF) and a photoelectric detector (PD). The PDM-MZM is used to carry out carrier suppressed double side band modulation on radio frequency (RF) and local oscillation (LO) signals and then implement frequency mixing, and the RF and LO isolation degree of frequency conversion gain and frequency conversion signals is improved. Optical signals output by the modulator can be divided into multiple paths to implement fiber transmission, each path is adjusted via an independent polarization state, and power attenuation caused by dispersion can be compensated.
Owner:XIDIAN UNIV +1

Method and system for 80 and 160 gigabit-per-second QRZ transmission in 100 GHz optical bandwidth with enhanced receiver performance

Optical transmitter / receivers for use in a DWDM systems are provided. Transmission of data signals in a quadrature-return-to-zero (QRZ) format achieves a data transmission rate equal to eight times a base data rate, i.e., 80 Gbps over a 100 GHz channel if the base data rate is 10 Gbps, with high non-linear performance by setting the polarization state of the data bands such that non-linear effects induced by PMD are reduced. Additionally, a transmitter achieves a transmission data rate equal to 16 times the base data rate by sharpening the QRZ pulses and interleaving pulse-sharpened QRZ data signals in the time domain, further doubling the data rate. Using counterpropagation in the transmitter, carrier signals and data signals traverse the same length of fiber, reducing fringing effects in the transmitter. Related techniques enhance reception and detection of data at high data rates. A local pulse-sharpened carrier is mixed with a QRZ data signal at a detector reducing amplification noise by a factor of two. A bi-directional Erbium-doped fiber amplifier is used to amplify a carrier signal while limiting fringing effects by sending carrier and data signals along equal optical path lengths. Non-linear effects are reduced by transmitting carrier signals in an othogonal polarization state with respect to data signals, and PMD phase noise effects are compensated for in both single channel and DWDM multi-channel systems by using delay management.
Owner:TERADVANCE COMM

Method and apparatus for free-space optical communication without eletro-optical conversion

Erbium doped fiber amplifiers (ERDAs) optically couple optical signals between free-space and fiber optic links of a terrestrial optical communication network. The optical gain of transmitting and receiving ERDAs is controlled to achieve good optical signal communication. Control occurs in response to signals received at the transmitting and receiving ends of the links. Control, status and management information may be communicated optically between link head stations. The physical position of transceivers at opposite ends of the link optical signal paths is also controlled.
Owner:LIGHTPOINTE COMM

Quadruplicated frequency millimeter wave generation method based on double-parallel MZ (Mach-zehnder) modulator

The invention relates to the field of an ROF (Radio Frequency Oscillator). The embodiment of the invention discloses a quadruplicated frequency millimeter wave generation method based on a double-parallel MZ (Mach-zehnder) modulator (DPMZM). The method comprises the main steps of: taking a laser source as a carrier, and loading the carrier on two arms of a main modulator; driving two MZ sub-modulators of an integrated modulator through the same radio frequency local oscillator, wherein a phase difference is pai; and amplifying through an EDFA (Erbium Doped Fiber Amplifier), beating frequency through PD (Potential Difference), and obtaining a quadruplicated radio source frequency millimeter wave signal.
Owner:BEIJING UNIV OF POSTS & TELECOMM

A method for realizing microwave signal photonics frequency conversion and multi-channel phase shift by using a dual-polarization quadrature phase shift keying modulator

The invention discloses a method for realizing photonic frequency conversion and multi-channel phase shift of a microwave signal by using a dual-polarization quadrature phase shift keying (DP-QPSK) modulator, relates to the technical field of microwaves and the technical field of optical communication, and can be mainly applied to beam forming, IQ demodulation and the like of the signal. As shownin an attached drawing, the scheme comprises a light source, a local oscillation source, an erbium-doped optical fiber amplifier, an optical splitter, a polarization controller, a polarizer and a photoelectric detector. According to the invention, the DP-QPSK modulator is used for carrying out modulation and polarization multiplexing on a radio frequency signal and a microwave local oscillator, after light amplification, power is divided into multiple paths, each path controls the amplitude and phase of an output signal through the polarization controller and the polarizer, and finally a phase-changed intermediate frequency signal is obtained through the photoelectric detector. According to the invention, the up-down frequency conversion and phase shift functions of signals can be realizedat the same time, the influence caused by periodic power fading is avoided, the system gain is large, and the system has the characteristics of simple structure, flexible tuning, large bandwidth, multiple functions and the like.
Owner:XIDIAN UNIV

Sensor for detecting the temperature and vibration position of fully distributed optical fiber

The invention discloses a sensor for detecting the temperature and vibration position of a fully distributed optical fiber. The sensor adopts a laser, a pulse generator, an acousto-optic modulator, an isolator, an erbium-doped fiber amplifier, a circulator and a Raman wavelength division multiplexer to send two pulse signals with different sizes to the fully distributed optical fiber; the returned signals receive the treatment of the Raman wavelength division multiplexer, an avalanche diode and a data collector, and a computer processes collection data in the time of one of the pulse signals to obtain the temperature; the returned signals receive the treatment of the Raman wavelength division multiplexer, the circulator, a Rayleigh scattered-light processing unit and the data collector, and the computer processes collection data in the time of the other of the pulse signals to obtain the vibration position. The sensor for detecting the temperature and vibration position of the fully distributed optical fiber can monitor the temperature and vibration position on the same optical fiber at the same time, the whole cost is much smaller than that of the superposition of two individual systems, the measurement precision is high, and the measurement is convenient and quick.
Owner:CHINA UNIV OF GEOSCIENCES (WUHAN)

Apparatus and method used for automatic test of erbium-doped fiber amplifier performance

The invention provides a device for automatically testing the performance of an erbium doped fiber amplifier (EDFA). Special software is adopted to automatically control and operate the detection device so as to realize the automatic tests of the gain flatness, transient response and signal-to-noise ratio of the EDFA. Manual intervention is not needed in the whole test process. The automatic test device of the EDFA can largely reduce device setting time, optical path switching time and the test recording and analysis time which are consumed by manual operation, and can further avoid human error caused by manually recording test data. The automatic test mode of the device causes the operation of EDFA performance test to be simple, fast and reliable, which greatly improves the efficiency of the EDFA performance test, and can fully meet the application requirement of enterprises for mass EDFA tests.
Owner:WUXI TACLINK OPTOELECTRONICS TECH CO LTD

Methods of achieving optimal communications 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.
Owner:MASSACHUSETTS INST OF TECH

Dynamic distributed Brillouin optical fiber sensing device and method

ActiveCN103335666AAchieve frequency agilityRealize dynamic sensingConverting sensor output opticallyData acquisitionErbium doping
The invention discloses a dynamic distributed Brillouin optical fiber sensing device and method, belongs to the optical field, and solves the problem of small strain measurement range in a dynamic sensing technology based on a Brillouin gain slope method. The dynamic distributed Brillouin optical fiber sensing device comprises a laser, a coupler, a to-be-measured polarization maintaining optical fiber, an erbium-doped fiber amplifier, an adjustable optical attenuator, a data acquisition module, a first polarization controller PC1, a second polarization controller PC2, a third polarization controller PC3, a fourth polarization controller PC4, a probe light intensity modulator IM1, a pump light intensity modulator IM2, an arbitrary waveform generator (AWG), a first circulator R1, a second circulator R2, a first signal amplifier Amp1 and a second signal amplifier Amp2. According to the invention, the intensity modulators can be driven by arbitrary waves, so that the frequency agility of probe light is realized, the fast frequency scan problem is solved, the distributed Brillouin dynamic sensing is achieved, and the strain of the to-be-measured polarization maintaining optical fiber is measured.
Owner:HARBIN INST OF TECH

Method for measuring gain and noise factor of erbium-doped fiber amplifier

The present invention discloses a method for measuring the gain and noise coefficients of the erbium-doped optical amplifier; the measurement comprises the following steps that a DFB light source can be input into a filter through a variable optical attenuator; the output end of the filter is connected with an optical power meter to obtain the input power Pin of EDFA; the input end of the EDFA is suspended and the flat region of the ASE spectrum in the EDFA is utilized for obtaining the ASE power PASE which is in the filter band width from the optical power meter; the DFB light resource signal can be emitted into the EDFA through the variable optical attenuator and the signal amplified by the EDFA and the ASE mixing power Pout are obtained from the optical power meter through the filter; by alternating the variable optical attenuator value, the EDFA gain and noise coefficient curves can be calculated and described. The beneficial effect is that the present invention utilizes the flat region of the ASE spectrum in the EDFA to match with a band-pass filter which can fast and accurately calculate EDFA gain and noise coefficients. The test method of the present invention is simple which greatly reduces measurement cost.
Owner:天津市金飞博科技有限公司
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