39results about How to "No insertion loss" patented technology

A compensation method of current sensor includes real-time detection of magnetic induction density and outputting current with proper phase and magnitude via the feedback circuit for tracking compensation of the exciting current in magnetic core. A zero-flux microcurrent sensor designed based on the method has two superposed annular working magnetic cores and auxiliary magnetic core with wound primary coil, secondary coil and compensating coil as well as shielding and protecting casing outside the magnetic core. The microcurrent sensor features the primary and secondary coils on the superposed core, the secondary coil with load across it, one detection coil on the working core, a compensation coil on the auxiliary core, electronic regulating circuit comprising amplifier and voltage-to-current converter connected between the detection coil and the compensation coil.

An LVDS low swing difference signal bus digital intermediate frequency transmission method is provided. A front end intermediate frequency sampling processing unit consists of an AD chip, a DSP and a FPGA control chip group. The base-band processing is inside the FPGA. An LVDS difference transmission control unit consists of an LVDS driving chip and an FPGA control chip group. The data bidirectional transmission is realized through a controller consisting of the FPGA and the LVDS driving chips. The LVDS difference transmission control unit also comprises a signal processing board and a channel board. A parallel-serial transform sending module and a serial- parallel transform receiving module are arranged. The signal processing board and the channel board are connected through a balance transformation difference cable. When the information is received, the digital signals sampled from the analog intermediate frequency signals through a high-speed A / D are processed and then are exportedinto an FPGA buffer memory through an external bus. The data encoding framing, decoding frame and transforming control are accomplished in FPGA. The data are then exported to a signal processing board through an LVDS controller interface after going through the difference balance.

The invention discloses a radio frequency modulation tunable all-fiber laser based on a fiber loop mirror. The radio frequency modulation tunable all-fiber laser based on the fiber loop mirror is characterized in that one arm of the fiber loop mirror, a dual-cladding non-doped fiber, a dual-cladding doped fiber, a signal optical channel of a wavelength division multiplexer and an output tail fiber are sequentially connected in a welding mode end-to-end. A pumping source is connected with a pumping source optical channel of the wavelength division multiplexer in a welding mode. A fiber fixing traction support comprises a left lobe and a right lobe. The dual-cladding non-doped fiber is wound in a groove outside the fiber fixing traction support and tightened. A triangular prism support is arranged on piezoelectric ceramic, and cushion blocks are arranged at the bottom of the piezoelectric ceramic. The piezoelectric ceramic is connected with a radio frequency power source. According to radio frequency modulation tunable all-fiber laser based on the fiber loop mirror, by the adoption of the tuned radio frequency mode, ultrasonic vibration is utilized to form a long period fiber grating with an adjustable period, wavelength tuning of the fiber laser is achieved, a full-fiber structure without discrete component is adopted in the fiber laser, and no inserting loss is generated, so that optical quality is good, output power is high, the structure is compact, performance is stable and reliable, and continuous tuning in a wide range can be achieved.

The invention discloses a household electric power safety intelligent monitoring system, which comprises a hall voltage sensing module, a current sensing module, and a single-chip microcomputer main control chip, a comparator, a wireless WIFI module, a power loop cut-off switch and an acousto-optic alarm module which are integrated on a circuit board. According to the system, the voltage amplitudecan be set to exceed a certain value, and an outage and an alarm can be started; due to the fact that hall non-contact voltage overload detection is adopted, the safety is high, the response speed reaches an ms level, the precision can reach 0.2%, and the insertion loss does not exist; a connection with a remote mobile terminal is realized through a wireless router, and rapid dealing is achieved.

The invention discloses a superheterodyne receiver as well as a method and device for improving measurement accuracy thereof. The device comprises an attenuation detection unit, a power calibration unit and a power compensation unit, wherein the attenuation detection unit is used for detecting the attenuation of a programmable attenuator of a superheterodyne receiver when the superheterodyne receiver measures a measured component; the power calibration unit is used for detecting and recording the corresponding power calibration values of the superheterodyne receiver under a plurality of specific attenuation by adjusting the attenuation of the programmable attenuator of the superheterodyne receiver; and the power compensation unit is used for implementing gain compensation on the superheterodyne receiver by using the attenuation measured by the attenuation detection unit and the power calibration values recorded by the power calibration unit, and thus the accuracy of power measurement of the superheterodyne receiver in impedance mismatch can be increased, and as no additional circuit is added to a signal path in which the superheterodyne receiver measures the measured component, the insertion loss cannot be introduced, and time delay also cannot be increased.

The invention is applicable to the technical field of radar antennas, and provides a series-fed microstrip antenna, which comprises a series-fed antenna, a first coupled antenna and a second coupled antenna which are arranged on the front surface of a substrate, a grounding metal plate arranged on the back surface of the substrate, and a first grounding hole and a second grounding hole which penetrate through the substrate, wherein the first coupled antenna and the second coupled antenna are arranged on the two sides of the series-fed antenna in parallel, and are separated from the series-fedantenna by a first preset distance and a second preset distance respectively, and the first coupled antenna and the second coupled antenna are respectively connected with the grounding metal plate through the first grounding hole and the second grounding hole. According to the invention, the maximum beam pointing direction of the series-fed antenna can be changed, the 3db beam width is broadened,no extra insertion loss is generated, and the radiation efficiency of the antenna is effectively improved.

The invention discloses an all-fiber annular tunable fiber laser. The all-fiber annular tunable fiber laser comprises a first wavelength division multiplexer, a doubly-clad doped fiber, a second wavelength division multiplexer and a tunable filter. A pumping arm, a signal injection end and a beam combination end of the first wavelength division multiplexer are connected with a pumping source, a doubly-clad non-doped fiber and the doubly-clad doped fiber in a welding mode respectively, and a signal injection end, a first beam split arm and a second beam split arm of the second wavelength division multiplexer are connected with the doubly-clad doped fiber, the doubly-clad non-doped fiber and an output tail fiber. The tunable filter comprises a fiber fixing drawing support, a triangular prism support, a piezoelectric ceramic, a cushion block and a radio-frequency power supply, wherein the fiber fixing drawing support comprises a left section and a right section, the doubly-clad non-doped fiber is wound in grooves on the outside of the fiber fixing drawing support and is tensioned, and the piezoelectric ceramic is connected with the radio-frequency power supply. The all-fiber annular tunable fiber laser is free of insertion loss, good in beam quality, high in output power, compact in structure, stable in performance, and capable of achieving continuous tuning in a wide range.

The invention discloses a radio frequency modulation tunable all-fiber laser with stable power control. The radio frequency modulation tunable all-fiber laser is characterized in that a first fiber annular mirror, a double-clad non-doped fiber, a double-clad doped fiber, a signal light channel of a wavelength division multiplexer and a second fiber annular mirror are sequentially in butt fusion end to end, a second arm of the first fiber annular mirror is connected with a light power meter, the light power meter is connected with a controllable semiconductor laser power source, and the controllable semiconductor laser power source is connected with a pumping source; the pumping source is in butt fusion with a pumping light channel of the wavelength division multiplexer, and a second arm of the second fiber annular mirror is connected with an output tail fiber; the double-clad non-doped fiber is wound on a fiber fixing stretching support; a piezoelectric ceramic is connected with a radio-frequency power source. The radio frequency modulation tunable all-fiber laser with the stable power control has the advantages that an all-fiber structure without discrete components is adopted, insertion loss is avoided, beam quality is high, output power is high, structure is compact, performance is stable and reliable, and continuous tuning in a wide range can be achieved.

The invention belongs to the technical field of wireless communication, in particular to a waveguide polarization device and a combiner of the waveguide polarization device. The waveguide polarization device comprises a rectangular waveguide located on a central axis, four small waveguides are embedded on four wide edge corners of the rectangular waveguide, wherein the cross sections of the four small waveguides are rounded rectangles, and the four small waveguides are symmetrical in pairs relative to the rectangular waveguide. The combiner comprises the polarization device and two combiner rectangular waveguide openings, wherein the polarization device is located on an identical central axis and symmetrically and rotatably arranged relative the central axis, and the polarization device is located between the two combiner rectangular waveguide openings. The waveguide polarization device is simple in structure and excellent in performance, almost no insertion loss exists after the waveguide polarization device is mounted, return loss is extremely low, the polarization device does not need to be rotated or replaced, two polarization modes of horizontal polarization and vertical polarization can be achieved simultaneously, in engineering use, workload of constructors on a tower can be reduced, construction cost is reduced, and meanwhile quality risks are also reduced.

The invention discloses a method for all-fiber Q-switching through continuous acoustooptic diffraction. A plurality of groups of piezoelectric transducers act on gain fibers of a fiber laser, the piezoelectric transducers are connected with a plurality of paths of radio frequency signal sources, and each group of the piezoelectric transducers at least consist of two piezoelectric transducers; the emergence angle of a synthetic sound wave generated by a piezoelectric transducer array is changed by changing the phase of an input radio frequency signal of the piezoelectric transducer array in each group of the piezoelectric transducers, so that the emergent angle satisfies a sound wave incident angle of Bragg diffraction; with a plurality of groups of acoustooptic Bragg diffractions, the laser light in the gain fibers breaks away from the limitation of a numerical aperture, and the Q-value of the laser is reduced; and when a sound wave field formed by the piezoelectric transducers disappears, phase gratings in the gain fibers disappear, and the laser is in a high Q-value state. The method is used for solving the problem of adopting the lower incident sound wave frequency and the lower sound wave power density to finish the Q-switching of the fiber laser.

The invention discloses a design method of a broadband miniaturized VICTS antenna feed network, which comprises the following steps: determining the hierarchy of a power division network according tothe transverse size of a feed network, and determining the number of T-shaped junctions according to the hierarchy of the power division network and the longitudinal size of the feed network; analyzing a field mode propagated in the waveguide, calculating a main mode starting frequency and a main mode ending frequency, establishing a miniaturized T-junction model, and establishing a relationship between a T-junction structure parameter and a reflection coefficient; adopting a broadband technology to design a broadband and miniaturized T-junction, and adopting a full-wave analysis method to extract the relationship between the broadband T-junction and a reflection coefficient; The amplitude and the phase of the T-junction are adjusted, so that the T-junction meets the in-phase excitation output of specific power distribution; and designing a port conversion module and a transition matching and polarization adjusting module, and checking related indexes of the excitation source to reachset indexes. Effective compression of the longitudinal size of the feed network is achieved, in-phase output is achieved within the required frequency band range, meanwhile, the amplitude is accurately controlled, and therefore the gain and standing wave characteristics of the antenna are guaranteed.

The invention discloses a tunable small wavelength interval equipower dual-wavelength optical fiber laser which comprises a first optical fiber annular mirror, an optical fiber fixing and pulling support, a triangular vibration transmitter, piezoelectric ceramics, a cushion block, a radio-frequency power source, double cladding non-doped fibers, double cladding doped fibers, a wavelength division multiplexer, a pumping source, a second optical fiber annular mirror, output tail fibers, a collimating lens, a reflecting grating, a first optical power meter, a second optical power meter and an automatic frequency control circuit. The optical fiber annular mirrors, the double cladding non-doped fibers, the double cladding doped fibers and the multiplex end of the wavelength division multiplexer are sequentially connected in a welding mode, and the pumping end of the wavelength division multiplexer is connected with the pumping source in a welding mode. The signal end of the wavelength division multiplexer is connected with the second optical fiber annular mirror in a welding mode. The automatic frequency control circuit is connected with the radio-frequency power source. The tunable small wavelength interval equipower dual-wavelength optical fiber laser is of an all-fiber structure without discrete components, has no insertion loss, and has the advantages of being good in beam quality, high in output power, compact in structure, stable and reliable in performance, and capable of achieving small interval tunable dual-wavelength equipower laser output.

The invention discloses a non-contact electromagnetic valve detection system and a detection method. The detection system includes a magnetic field sensor, a conditioning amplifier circuit, an A / D acquisition board, a multifunctional measurement and control board, and an industrial computer; The surroundings of the solenoid valve are connected with a conditioning amplifying circuit; the A / D acquisition board is connected with the conditioning amplifying circuit, and simultaneously connected with a multifunctional measurement and control board; the multifunctional measurement and control board is respectively connected with an industrial computer and a power drive circuit board. In the present invention, the inductive magnetic sensitive sensor has no contact sensing, high reliability, and is used to detect current and voltage. It can perform positionless detection without connecting to the main circuit, has no insertion loss, and realizes complete isolation of input and output signals. , no overload damage; and the adaptive filtering algorithm software adopted can extract and suppress the noise part of the composite signal, which can eliminate the interference noise signal, thereby obtaining a complete original signal and improving the test accuracy.

The invention discloses a signal surge protector capable of automatically switching based on lightning early warning information and an operation method. The signal surge protector comprises a power supply module, an automatic switching control module, a switching switch module, a surge protection module, a signal transmission indication module, a surge protector working state indication module and a transmission signal compensation module, wherein the surge protection module is connected with the transmission compensation module and the surge protector working state indication module, an administrator management module issues a system starting handshake command signal handshake, and the automatic switching control module receiving the handshake signal is awakened, performs response handshake with the administrator management module once at regular intervals according to initial program setting, reports the zone bit number and the working state of the automatic switching control module, forwards the zone bit numbers and the working states of other control modules received by the automatic switching control module, and ensures stable construction of the communication bridge. The signal surge protector integrates the advantages of large through-flow, low residual voltage, no insertion loss, low standing-wave ratio, small error rate, no introduction of near-end crosstalk and the like.

The invention belongs to the technical field of non-classical optics, and discloses a non-classical light field generator with phase self-compensation. The non-classical light field generator comprises a laser, a compressed light field generator, a first phase shifter, a beam splitter, a central controller, a balanced zero-beat detector and a spectrum analyzer; the compressed light field generatoris used for generating a compressed light field detected by the balanced zero-beat detector; an output signal of the balanced zero-beat detector is connected with the spectrum analyzer; an output endof the spectrum analyzer is connected with the central controller; an output end of the central controller is connected with an input end of a temperature controller, is used for changing the crystaltemperature through the temperature controller, finding the double resonance temperature of an optical parametric cavity amplifier according to the output signals of the single detectors at differentcrystal temperatures, and is further used for finding the phase self-compensation temperature of the optical parameter amplifier according to output signals of a single detector at different crystaltemperatures; and is further used for finding the phase self-compensation temperature of an optical parameter amplifier according to the compression degree of a first compressed light field at different crystal temperatures. The non-classical light field generator with the phase self-compensation provided by the invention improves the non-classical characteristics of the light field and can be applied to the field of non-classical light fields.

The invention discloses a magnetic force induction long-period fiber Bragg grating Q-switching pulse and continuous dual-purpose fiber laser. The magnetic force induction long-period fiber Bragg grating Q-switching pulse and continuous dual-purpose fiber laser comprises a pumping source, a total reflection fiber Bragg grating, a double-clad doped fiber, an output fiber Bragg grating and an output tail fiber, wherein the pumping source, the total reflection fiber Bragg grating, the double-clad doped fiber, the output fiber Bragg grating and the output tail fiber are connected end to end. The magnetic force induction long-period fiber Bragg grating Q-switching pulse and continuous dual-purpose fiber laser further comprises a magnetic force induction long-period fiber Bragg grating which comprises a periodic irony component, a coil and an iron core, wherein the coil is wound outside the iron core, the periodic irony component is arranged on the iron core, and the tail end of the double-clad doped fiber is clamped between the periodic irony component and a support. According to the magnetic force induction long-period fiber Bragg grating Q-switching pulse and continuous dual-purpose fiber laser, when the coil is powered on, the double-clad doped fiber is extruded to form the long-period fiber Bragg grating, so that loss inside the double-clad doped fiber is increased, an oscillation threshold value of the laser is increased, and stored energy in fiber cores is increased. When the coil is powered on through periodic square wave currents, the long-period fiber Bragg grating which appears periodically is formed, and accordingly laser Q-switching output with repeatability is formed. When the coil is not powered on, the laser can also be used as a continuous laser.

The invention discloses a radio frequency front-end structure applied to a GNSS dual-frequency receiver. It solves the problem in the prior art that the signal at the output end of the broadband low-noise amplifier needs to be connected to a power divider to drive the circuit module, which increases the cost and makes the front-end structure of the GNSS dual-frequency receiver more complicated. The structure includes a dual-frequency antenna, a broadband low-noise amplifier and a SOC processing chip. The dual-frequency antenna is connected to the input end of the broadband low-noise amplifier, and the output end of the broadband low-noise amplifier is divided into two branches, and the two branches are connected respectively after connecting the circuit module. On the RF input of the SOC processing chip. The output end of the broadband low-noise amplifier of the invention is directly connected with two subsequent circuit modules, eliminating the need for a power divider and greatly reducing the cost of the receiver; without the need for a power divider, the area of ​​the receiver is reduced and the receiver is improved. The integration level of the system; the insertion loss of the power divider is eliminated, the circuit complexity is reduced, and the performance of the receiver is improved.

The invention relates to an antenna system configuration technology in the field of Internet of things, and discloses an antenna system of areconfigurable radiation mode, which solves the problem thatthe connecting distance of the traditional Internet of Things antenna system is limited by adopting the omni-directional radiation modewhile external insertion loss is introduced and system cost is increased in a scheme by adopting a beamforming technology for increasing the antenna directionness. The antenna system includes a set of drive elements and parasitic elements located on a ground plane; The parasitic element group comprises parasitic elements distributed around the driving elements, and each parasitic element is composed of upper and lower parts, and the upper and lower parts and the lower part and the ground plane are connected with controllable switches. The invention is applicable to scenarios in which a wireless system needs to be arranged in the field of the Internet of Things.

The invention relates to the field of a multi-modulation mode multifunctional laser device and an output method based on a monolithic double 45°-MgO:LN. The device includes: front cavity mirror, pump source, laser gain medium, double 45°‑MgO: LN crystal, acousto-optic crystal, first output mirror, second output mirror, first block doped MgO: LN Crystal, the second horizontal back-pressure electro-optic modulator, the first Brewster mirror, the s-light full reflection mirror with electric guide rail, the p-light output mirror, the first optical isolator switch, the electro-optic control device, the acousto-optic modulator , the second optical isolator switch, the p-light total reflection mirror with electric guide rail, the s-light output mirror, the electro-optic control device is connected with the double 45°-MgO: LN crystal, the second horizontal back pressure electro-optic modulator Connected to the first bulk doped MgO:LN crystal. The invention can realize switching among three modulation modes of high repetition frequency acousto-optic Q-switched pulse laser, high-power electro-optic Q-switch pulse laser and electro-optic cavity emptying with narrow pulse width and high peak power, and has high integration and easy operation.

The invention discloses a radio frequency modulation tunable all-fiber laser based on a fiber loop mirror. The radio frequency modulation tunable all-fiber laser based on the fiber loop mirror is characterized in that one arm of the fiber loop mirror, a dual-cladding non-doped fiber, a dual-cladding doped fiber, a signal optical channel of a wavelength division multiplexer and an output tail fiber are sequentially connected in a welding mode end-to-end. A pumping source is connected with a pumping source optical channel of the wavelength division multiplexer in a welding mode. A fiber fixing traction support comprises a left lobe and a right lobe. The dual-cladding non-doped fiber is wound in a groove outside the fiber fixing traction support and tightened. A triangular prism support is arranged on piezoelectric ceramic, and cushion blocks are arranged at the bottom of the piezoelectric ceramic. The piezoelectric ceramic is connected with a radio frequency power source. According to radio frequency modulation tunable all-fiber laser based on the fiber loop mirror, by the adoption of the tuned radio frequency mode, ultrasonic vibration is utilized to form a long period fiber grating with an adjustable period, wavelength tuning of the fiber laser is achieved, a full-fiber structure without discrete component is adopted in the fiber laser, and no inserting loss is generated, so that optical quality is good, output power is high, the structure is compact, performance is stable and reliable, and continuous tuning in a wide range can be achieved.

The application discloses a bias circuit for a power amplifier. The bias circuit is used to provide a static operating current to the power amplifier. The bias circuit includes a bias connection terminal, a DC power supply connection terminal, a self-resonant circuit, and a decoupling filter circuit. , Transistor Q1, power sharing circuit and work holding circuit. The self-resonant circuit is used to curb the reverse flow of the AC signal output by the power amplifier, and also prevent the leakage of high-frequency signal energy. The decoupling filter circuit is used to reduce the Q value of the self-resonant circuit. The power sharing circuit is used to share the output power of the DC power supply. The work holding circuit is used to ensure the stable operation of the triode Q1, and then provide a stable quiescent working current to the power amplifier. Since the ultra-wideband bias circuit is realized through the triode amplifier circuit with a DC source, it can not only provide a normal operating voltage difference for the power amplifier, but also not bring too much device insertion loss to the power amplifier, so that the gain of the power amplifier can be obtained. improve.

A compensation method of current sensor includes real-time detection of magnetic induction density and outputting current with proper phase and magnitude via the feedback circuit for tracking compensation of the exciting current in magnetic core. A zero-flux microcurrent sensor designed based on the method has two superposed annular working magnetic cores and auxiliary magnetic core with wound primary coil, secondary coil and compensating coil as well as shielding and protecting casing outside the magnetic core. The microcurrent sensor features the primary and secondary coils on the superposed core, the secondary coil with load across it, one detection coil on the working core, a compensation coil on the auxiliary core, electronic regulating circuit comprising amplifier and voltage-to-current converter connected between the detection coil and the compensation coil.

A large-scale integrated optical switch chip based on an optical phased array is characterized by comprising a silicon-based phased array emission chip and a silicon-based phased array reception chipwhich are arranged opposite to each other and in parallel, the silicon-based phased array emission chip includes a 2D array composed of N*N optical phased array units, and each optical phased array unit is composed of a light beam splitter in a front input port, a phase modulator in the middle and a light emitting port in the tail end. The large-scale integrated optical switch chip is characterized by being completely free of obstruction, high in speed, low in insertion loss and low in crosstalk, and can satisfy requirement for large capacity data exchange of optical communication and opticalinterconnection network.

The invention discloses a method for improving a Raman threshold value of an optical fiber laser system and application, and belongs to the technical field of optical fiber lasers. The method for improving the Raman threshold value of the optical fiber laser system comprises the step of carrying out mode scrambling on an energy transmission optical fiber in the optical fiber laser system by adopting a mode scrambler so as to improve the Raman threshold value. The corresponding optical fiber laser system comprises a laser module, an output optical cable and a mode scrambler, wherein the laser module and the output optical cable are connected through the energy transmission optical fiber; the mode scrambler is located between the laser module and the output optical cable and used for conducting mode scrambling on the energy transmission optical fiber so as to improve the Raman threshold value. An optical fiber device does not need to be fused in a laser system and the structure of an optical system does not need to be changed, operation is easy, insertion loss does not exist, the Raman threshold value improving effect is obvious, and meanwhile the method is suitable for a high-power laser system.

The invention discloses a radio frequency front-end spread spectrum and despread prescription method based on an amplifier drain electrode modulation effect, and relates to the technical field of wireless communication. The method comprises: performing power division on an input radio frequency signal; performing 180-degree phase shift on one path of signal; generating two branch radio frequency signals, the two branch radio frequency signals are respectively transmitted to the two power amplifiers or the two low noise amplifiers. By means of the drain electrode modulation effect, multiplyingof each branch radio frequency spread spectrum signal and a drain electrode power supply signal of a power amplifier or a low-noise amplifier corresponding to the branch is achieved, spread spectrum or despread processing is completed, and the spread spectrum and despread method can achieve the radio frequency front-end spread spectrum and despread function which is free of insertion loss and canflexibly configure a spread spectrum code.

The invention discloses a method for all-fiber Q-switching through continuous acoustooptic diffraction. A plurality of groups of piezoelectric transducers act on gain fibers of a fiber laser, the piezThe invention discloses a method for all-fiber Q-switching through continuous acoustooptic diffraction. A plurality of groups of piezoelectric transducers act on gain fibers of a fiber laser, the piezs, phase gratings in the gain fibers disappear, and the laser is in a high Q-value state. The method is used for solving the problem of adopting the lower incident sound wave frequency and the lowerars, phase gratings in the gain fibers disappear, and the laser is in a high Q-value state. The method is used for solving the problem of adopting the lower incident sound wave frequency and the lower sound wave power density to finish the Q-switching of the fiber laser.sound wave power density to finish the Q-switching of the fiber laser.oelectric transducers are connected with a plurality of paths of radio frequency signal sources, and each group of the piezoelectric transducers at least consist of two piezoelectric transducers; theoelectric transducers are connected with a plurality of paths of radio frequency signal sources, and each group of the piezoelectric transducers at least consist of two piezoelectric transducers; theemergence angle of a synthetic sound wave generated by a piezoelectric transducer array is changed by changing the phase of an input radio frequency signal of the piezoelectric transducer array in eacemergence angle of a synthetic sound wave generated by a piezoelectric transducer array is changed by changing the phase of an input radio frequency signal of the piezoelectric transducer array in each group of the piezoelectric transducers, so that the emergent angle satisfies a sound wave incident angle of Bragg diffraction; with a plurality of groups of acoustooptic Bragg diffractions, the laseh group of the piezoelectric transducers, so that the emergent angle satisfies a sound wave incident angle of Bragg diffraction; with a plurality of groups of acoustooptic Bragg diffractions, the laser light in the gain fibers breaks away from the limitation of a numerical aperture, and the Q-value of the laser is reduced; and when a sound wave field formed by the piezoelectric transducers disapper light in the gain fibers breaks away from the limitation of a numerical aperture, and the Q-value of the laser is reduced; and when a sound wave field formed by the piezoelectric transducers disappear

The invention discloses a bias circuit for a power amplifier, the bias circuit is used for providing static working current for the power amplifier, and the bias circuit comprises a bias connection end, a direct current power supply connection end, a self-resonance circuit, a decoupling filter circuit, a triode Q1, a power sharing circuit and a work holding circuit. The self-resonance circuit is used for restraining backflow of alternating current signals output by the power amplifier and preventing leakage of high-frequency signal energy. The decoupling filter circuit is used for reducing the Q value of the self-resonance circuit. The power sharing circuit is used for sharing output power of the DC power supply. The work holding circuit is used for guaranteeing stable work of the triode Q1, and then stable static working current is provided for the power amplifier. Due to the fact that the ultra-wideband biasing circuit is achieved through the triode amplifying circuit with the direct-current source, normal working voltage difference can be provided for the power amplifier, excessive device insertion loss cannot be brought to the power amplifier, and the gain of the power amplifier is improved.

In WDM system, the chromatic dispersion compensation (CDC) based on multi-channel fiber raster (FR) includes wideband FR, sampling FR, super superpose FR and serial narrowband FR, etc. In all these forms, system interference includes both linear interference induced from limited extinction rate of FR and non-linear interference from cross phase modulation. This invention possesses restraint function over both linear and non-linear interference. The invention induces the cross phase modulation restrainer (CPMR) with random time-delay difference only between the neighbor channels. This chromatic dispersion compensator based on chirp fiber raster is practically an integrative scheme solving both CDC and CPMR. Its structure is simple without extra insertion loss. The system cost raises little.