44results about How to "Uniform gain" patented technology

Efficient delivery of large amounts of pump laser power distributed along the cladding (11, 54) of a single core (6) or multiple core (7, 51) laser fiber, without degrading the fiber integrity or compromising the fiber's waveguiding property, is accomplished by injecting the power into the cladding via delivery fibers (18, 30, 42, 62) permanently affixed to a peripheral wall (20, 56) at an angle that satisfies the condition for total internal reflection of the pump radiation so that it is confined within the inner cladding of the laser fiber. In one embodiment, the laser fiber (51) is wrapped around a drum (53). Each delivery fiber has a numerical aperture (NA) less than half the NA of the laser fiber, and a core 21 having a refractive index substantially the same as that of the inner cladding (11) of the laser fiber.

Optically controlled microwave beam forming networks comprise 2N single frequency DFB lasers of different wavelengths, , 2N electro-optic intensity modulators, 2N *1 passive wavelength division multiplexers, an optical fiber, 1*2N optical beam splitter, 2N fiber collimator, a time delay network module, 2N coupled lenses, 2N photoelectric detectors and 2N low noise amplifiers, wherein N is an integer larger than 2. The optically controlled microwave beam forming networks have the advantages of the high signal to noise ratio, good dynamic performance, high time delay precision, continuous adjustability, and good stability, and are easy to be extended in the system array size.

The present invention provides an amplifier for amplifying a high-frequency signal and outputting an amplified signal. The amplifier includes: an amplification element which is a bipolar transistor or a field-effect transistor; and an inductor connected between a base and a collector or between a gate and a drain of the amplification element. The inductance of the inductor is chosen so that, within a predetermined frequency range, a parallel resonance occurs with a parasitic capacitor of the amplification element and an intrinsic capacitor of the amplification element, the intrinsic capacitor being a base-collector capacitance or a gate-drain capacitance.

The invention provides a satellite data transmission antenna with the wide beam and even gain advantages. The satellite data transmission antenna is of a double-helical-antenna structure and carries out feed through a coaxial line (1). The satellite data transmission antenna is characterized in that a conical reflector cup (3) is arranged at the bottom end of the coaxial line (1) in a penetrating mode, and a concave hole (4) is formed in the bottom of the conical reflector cup (3). The satellite data transmission antenna is provided with the conical reflector cup, so that influence on the antenna from reflection of a satellite deck is reduced; for a small ground proximity detector, the antenna has the even gain distribution within the required beam range by designing parameters of helical antennas, and meanwhile gains not within the beam range can be rapidly decreased; the small antenna has the wide beam and even gain advantages.

An apparatus and method suppress unwanted signal components in receiving signals during wireless communication. A first circuitry is arranged to process a first signal, a second circuitry is arranged to apply transferred impedance filtering on a second signal according to a filter clock frequency, a signal branching circuitry is arranged to branch an input signal into the first circuitry and the second circuitry, and a signal combining circuitry is arranged to combine the processed first signal and the filtered second signal such that signal components of the first signal processed in the first circuitry and the filtered second signal are in-phase for signal frequencies equal to the filter clock frequency.

The invention discloses a quantum-classic common fiber transmission system based on mode division multiplexing. The quantum-classic common fiber transmission system comprises two classic signal transmitters, a QKD transmitter, a first mode multiplexer, a second mode multiplexer, an EDFA, a mode demultiplexer, an MIMO digital signal processing unit, two classic signal receivers, a QKD receiver anda transmission link. The transmission link adopts few-mode optical fiber transmission and comprises N erbium-doped optical fiber amplifiers. The receiving end comprises a mode demultiplexer, a digitalsignal processing MIMO, two classic signal receivers and a QKD receiver. On the basis of increasing the transmission capacity through mode division multiplexing, the power of the pump light in the erbium-doped optical fiber amplifier can be automatically adjusted according to the bit error rate of a classic signal receiving end and the bit error rate of a quantum signal receiving end, and MDL damage in an MDM system is reduced.

The invention relates to a three-core multilayer erbium-doped ion four-mode optical fiber with extremely small gain difference, which comprises a fiber core 1, a groove 2 and a cladding 3, wherein thefiber core 1 is positioned at the center of the optical fiber, the cladding 3 is positioned outside the fiber core 1, and the groove 2 is arranged in the cladding 3 at a position closer to the fibercore 1. The fiber core 1 is divided into three layers, namely, a central layer 1-1, an annular layer 1-2 and an outer core layer 1-3 which are tightly connected. Ion doping is mainly concentrated in the area of the fiber core 1, the fiber core 1 is divided into three layers of rings for doping, and the three layers of ion filling areas are the same as the refractive index distribution areas of thecentral layer 1-1, the ring layer 1-2 and the outer core layer 1-3 of the erbium-doped ion four-mode optical fiber respectively. Due to the refractive index distribution assisted by the three-layer core groove, the optical fiber has a relatively high mode refractive index difference, the inter-mode crosstalk can be weakened, and the bending loss during application is reduced. Moreover, the refractive index distribution is helpful for reducing the power filling factor difference of each module, the difficulty of particle doping distribution optimization can be greatly reduced, and the gain equalization is easier to realize.

The invention discloses a full-band navigation antenna. The full-band navigation antenna comprises an antenna top end loading A, an antenna top end loading B, a floor, four antenna elements A, four antenna elements B, four outer side antenna parasitic arms, four inner side antenna parasitic arms and four feed elements; each feed element comprises an outer arm and an inner arm; the four feed elements are uniformly distributed on the floor; the inner arm and the outer arm of the feed element generate resonance points to generate a double-frequency effect through the outer side antenna parasitic arms and the inner side antenna parasitic arms so as to realize the widening of the bandwidth to realize circular polarization through four power-splitting couplers of a main board circuit. The full-band navigation antenna has the advantages of simple structure, reasonable design, low material cost, wide frequency band, uniform gain of each frequency point and the like; all the functions can be realized by simply pasting the common FPC on the plastic surface without using special high-frequency materials; the antenna low elevation gain is higher; and the full-band navigation antenna is still good in signals in weak-signal areas.

The invention discloses an ultra-broadband adjustable terahertz wave source system based on optical feedback modulation gain equalization, which includes an optical feedback modulation gain equalization unit, a longitudinal mode selection unit, a ring resonator unit and a frequency mixing unit; the optical feedback modulation gain The balance unit is connected to one end of the longitudinal mode selection unit, the other end of the longitudinal mode selection unit is connected to the ring resonator unit, the output end of the ring resonator unit is connected to the frequency mixing unit, and the input end of the ring resonator unit is also connected to the pump light source . The invention introduces the optical feedback technology into the optically generated terahertz wave system, which can realize the generation of terahertz waves with low phase noise, high performance, high efficiency, ultra-narrow line width, and ultra-wideband; the system development cost is low, the signal spectrum purity is high, The tunable range is large, and there is no need to introduce complex mechanisms such as spatial hole burning, polarization hole burning, and nonlinear effects into the system.

The invention provides a layered doped step type weak coupling gain equalization four-mode erbium-doped optical fiber. The refractive indexes of the fiber core and the cladding of the optical fiber are integrally kept in a step type, the fiber core part is two or more layers of concentric circles which are adjacent in sequence, and the erbium-doped concentrations of the layers are different. The part with insufficient refractive index or surplus of each layer is supplemented or eliminated through co-doped elements. According to the optical fiber, under the condition that the number of modes isclose to that of transmission optical fibers, the mode gain difference is effectively reduced, and the good mode gain equalization characteristic is achieved. Meanwhile, due to the proper selection of the refractive index and radius of the optical fiber, the refractive index difference between the modes is large, the mode crosstalk is effectively reduced, and the application in optical communication and optical wavelength division multiplexing systems is facilitated.

The invention discloses a constant width beam forming method based on an FIR filter, wherein a received signal f (t, x) =[f(t, x0), ..., f(t, xm), ..., f(t, xM-1)] T of a microphone array is processedthrough a beam forming method to obtain an output signal which is shown in the description, wherein f (t, x) represents a sampled signal of the microphone array at a t time position of x, () T represents a matrix transpose, m represents a microphone index, wherein m=0,1,... M-1, M represents the number of microphone array elements, xm represents the array element positions corresponding to the mth microphone, and x=[x0, ... ,xm,... ,xM-1); N represents the order of the FIR filter followed by each microphone, the description represents the coefficient of the n-order FIR filter followed by themth microphone, the superscript * represents the conjugate, and Ts represents the delay between adjacent filters. The method can enable the array to have the same spatial response to input signals with different frequencies within the main lobe width, and the beam forming device with approximately constant beam width and low side lobe array response is designed by utilizing the symmetric properties of the FIR filter array and microphone uniform linear array.

The invention relates to an LED frequency spectrum adaptation underwater lamp. The LED frequency spectrum adaptation underwater lamp comprises a lens, a lamp base, an LED lamp panel and a light reflecting cup matched with the LED lamp panel; the lens is fixed to the lamp base, and the lamp base is composed of an upper portion and a lower portion; each of the upper portion and the lower portion is provided with eight connecting screw holes, and the upper portion and the lower portion are fixed through screws; the light reflecting cup and the LED lamp panel are meshed together through hole groove openings; the LED lamp panel is fixed to a table board on the lower portion of an inner cavity of the lamp base; and two O-shaped sealing ring grooves are formed in the upper portion of the inner cavity of the lamp base, and a preserved fixed screw hole and a power source plug interface are arranged at the bottom of the lamp base. High-power LEDs are adopted as a light source, and the lamp has the higher penetrating power under the water; the light energy utilization rate is improved; the component and the concentration of trace elements doped in LEDs are adjusted to achieve aim of frequency spectrum adjustment; gain of light absorbed by sea water is equalized within the limit of visible spectrum.

The invention discloses a multi-core erbium-doped super-mode optical fiber for gain equalization, and belongs to the field of special optical fibers, optical fiber communication and signal processing. The multi-core optical fiber comprises nineteen cores, comprising a central core (1), first-layer cores (1-1)-(1-6) and second-layer cores (2-1)-(2-12), wherein the nineteen cores are uniformly distributed in a regular hexagon shape and are positioned in the same cladding (2), the radius of each core is 4-6 [mu]m, and the distance between the cores is 10-16 mu m. Due to the fact that the space between the cores is small, the nineteen cores jointly form a high-refractive-index area (3), in the area (3), the optical fiber supports super-mode transmission, and the number of scalar modes supported by the optical fiber ranges from 4 to 15. Erbium ions are doped in the first-layer cores (1-1)-(1-6) and the second-layer cores (2-1)-(2-12) except the central core (1), so that the gain of a fundamental mode is reduced, and the gain balance of the fundamental mode and a high-order mode is realized.

The invention discloses a mobile data collection method for three-dimensional UASNs (underwater acoustic sensor networks) based on probability neighborhood cover sets. The method comprises the steps of establishing a probabilistic communication model of the 3D underwater acoustic sensor networks; establishing the probability neighborhood cover sets as stay points of an AUV based on the established probabilistic communication model of the 3D underwater acoustic sensor networks; planning a data collection path of the AUV based on the probability neighborhood cover sets and collecting data of a whole network. According to the method, through adoption of the probabilistic communication model, the data collection distance can flexibly adjusted according to probability demands; data collection is carried out by employing the AUV, the energy consumption of the sensor nodes for data transmission can be effectively reduced, and the network lifetime is prolonged; through establishment of the probability neighborhood cover sets, the AUV does not need to traverse all the sensor nodes, the data collection finishing time is effectively shortened, and the data delay is reduced; and through change of a value of a data transmission success rate rho and a data transmission number of turns, an effective solution for balancing information gain and data delay is provided.

The invention provides an optical fiber filter and an optical fiber amplifier, which can realize flat amplification of a few-mode optical signal, so that the optical power of each of a plurality of optical signal modes transmitted by a fiber core of the optical fiber filter can be controllably adjusted. The optical fiber filter comprises a fiber core, an inner cladding and an outer cladding. The refractive index of the fiber core, the refractive index of the inner cladding and the refractive index of the outer cladding are sequentially decreased. The fiber core is used for transmitting at least two different first optical signal modes. The inner cladding is used for transmitting at least two different second optical signal modes. At least one fiber grating is etched on the fiber core. At least part of optical power of a target first optical signal mode is only coupled to a target second optical signal mode at the fiber grating, the target first optical signal mode is one of the at least two first optical signal modes, and the target second optical signal mode is one of the at least two second optical signal modes.

A dual polarised omnidirectional antenna apparatus (20) capable of operating in transmit and receive, comprising at least two dual polarised directional antennas (21) configured to be mountable in a substantially equi-spaced distributed array around and pointing away from a platform, wherein the antenna apparatus (20) is configured such that, when operated in transmit, the dual polarised directional antennas operate in phase with each other to deliver a combined omnidirectional, dual polarised, performance. This increases operational bandwidth and mitigates interference effects in communications applications.

The invention relates to the technical field of optical communication, and discloses an optical power adjusting unit, device, system and method. The optical power adjusting unit comprises a monitoring module, an amplifier, a communication module and a controller. The controller determines a gain tilt adjustment value according to the second power data acquired from the communication module and the first power data acquired from the monitoring module, and adjusts the gain flatness of the gain spectrum of the amplifier based on the gain tilt adjustment value, thereby adjusting the power of the light of each wavelength in the second optical signal until the power of the light of each wavelength in the third optical signal in the received second power data reaches the preset power threshold. According to the invention, not only can the power of the optical signal be balanced quickly and accurately for the multi-wave transmission system, but also the gain flatness of the gain spectrum can be changed along with the change of the transmission link environment, so that the performance of the receiving end is always in an optimal state.

A method of producing a mold for use in duplicating a light diffusion sheet is provided. The method includes a step of conducting sandblasting for blasting abrasive material from a blast gun to a surface of a mold base material to form unevenness in the surface of the mold base material, wherein the abrasive material is blasted to the surface of the mold base material at a blast angle of less than 90 DEG .