285 results about "Polarization multiplexed" patented technology

The invention relates to an optical fiber communication sensing integrated architecture and a working method thereof. Comprising a sensing system laser, a coupler, a polarization beam splitter, a semiconductor optical amplifier, a polarization multiplexing communication transmitting system, a polarization wavelength two-dimensional demultiplexer, namely a WDM-PM device, a coarse wavelength division multiplexer MMI-WDM, a single-mode fiber, a polarization multiplexing communication receiving system, a polarization diversity double-balanced photoelectric detector PBPD, and an ROTDR and phi OTDR data processing unit. According to the invention, not only can high-capacity and long-distance communication under fusion of polarization multiplexing and wavelength division multiplexing be realized, but also sensing and communication can be fused through a wavelength division multiplexing system, the quality of sensing signals is improved through polarization diversity reception on the basis, and mutual promotion of communication and sensing is realized.

The invention discloses a design method of a monolithic polarization multiplexing dual-function super-structure lens device and the super-structure lens device, and belongs to the technical field of optical imaging. The designed device can respectively realize independent bright field and edge enhancement imaging functions according to the polarization state of incident light; the cross section of the nano unit forming the device is in an anisotropic C2 symmetrical shape, and the long axis and the short axis of the cross section are perpendicular to each other, so that linearly polarized light parallel to and perpendicular to the long axis in the polarization direction has independent phase delay after passing through the nano unit. A bright field and an edge enhancement imaging phase are respectively applied to a pair of orthogonal polarization states, so that the device can carry out bright field imaging in one polarization state and carry out edge enhancement imaging in the other polarization state, and the imaging efficiency can be improved under the conditions that other imaging devices are not needed and the resolution requirement is met. And dual-function imaging with relatively wide working bandwidth and relatively high imaging mode switching convenience is realized.

The invention relates to the technical field of optical devices, and provides a tunable metasurface structure, an imager and a target recognition method, the tunable metasurface structure comprises a first electrode layer, a second electrode layer, a liquid crystal layer and a metasurface layer; voltage is applied to the first electrode layer and the second electrode layer to control the turning direction of liquid crystal molecules in the liquid crystal layer so as to adjust the polarization state of light in an incident image; the metasurface layer performs different responses on light rays in different polarization states through polarization multiplexing, a left-hand circular polarization state and a right-hand circular polarization state are used for encoding positive and negative values of weights, and a multi-channel A * A light spot matrix is generated through spatial multiplexing, so that an emergent feature image is determined through the light spot matrix; different light spot brightness in the light spot matrix is used for representing different convolution kernel weights. The metasurface and the liquid crystal are combined to obtain a tunable structure, various coding information can be processed, and therefore the object recognition accuracy and robustness are improved.

The invention discloses an optical interconnection system on an optical chip and the optical chip, relates to the technical field of communication, and aims to solve the technical problem of low system data capacity in the wavelength division multiplexing technology in the prior art. The system comprises a micro-ring modulation device, a polarization combiner and a demultiplexer, the output end of the micro-ring modulation device is connected with the input end of the polarization combiner; the input end of the demultiplexer is connected with the output end of the polarization combiner; the micro-ring modulation device is used for performing signal modulation on TE0 polarized light and TM0 polarized light in the light source; the polarization combiner is used for combining the TE0 polarized light and the TM0 polarized light output by the micro-ring modulation device and outputting combined light; and the demultiplexer is used for decomposing the combined light into signals corresponding to a plurality of wavelengths. By combining the polarization multiplexing technology and the wavelength division multiplexing technology, the number of multiplexing channels of the optical interconnection system is multiplied, and the data capacity of the optical interconnection system is improved.

The invention belongs to the technical field of optical communication, and particularly relates to a low-complexity digital pre-equalizer based on frequency domain comb pilot channel estimation. The device comprises a data sending module, a channel response test module and a digital signal pre-equalization module, the data sending module comprises an initial comb signal generation part and a frequency component phase rotation part; the channel response test module comprises a signal frequency difference estimation and recovery part and a channel amplitude-frequency and phase-frequency response test part; the digital signal pre-equalization module comprises a filtering coefficient generation part and a sending signal convolution pre-equalization part; according to the invention, a frequency domain comb pilot signal is sent to analyze channel amplitude-frequency and phase-frequency response, so that a pre-equalizer for pre-compensating channel response at a sending end is generated; the method has the characteristics of high granularity, high precision, robust transmission signal system and the like, and can be applied to various scenes such as polarization multiplexing long-distance single-carrier coherent optical transmission, mode multiplexing short-distance intensity modulation direct detection systems and the like.

The invention discloses a design method for a metasurface non-staggered polarization multiplexing holographic display device, and the method comprises the steps: carrying out the phase analysis of an initial polarization detection signal according to a phase recovery algorithm, and obtaining phase analysis information; receiving an incident polarized light signal and an emergent polarized light signal to construct emergent light complex amplitude, and combining phase analysis information to obtain analysis parameters corresponding to all positions in the metasurface device; constructing corresponding structure-phase delay mapping according to scanning information obtained by scanning, and further performing matching mapping on the analysis parameters to obtain corresponding mapping information; according to the mapping information, microstructure geometric parameters of all positions in the metasurface device are restored, and metasurface device design information is obtained. According to the design method, the holographic display device capable of carrying out independent phase regulation and control on any three polarization states can be designed, and the limitation that a non-staggered metasurface can only aim at orthogonal polarization state regulation and control is broken through; moreover, high-spatial-resolution display imaging can be realized, and the imaging field angle is larger.

The invention discloses a method of an optical anti-turbulence device for polarization multiplexing spatial optical communication. The mode demultiplexer is connected with the optical fiber; the single-mode optical fiber array is respectively coupled with each spatial intrinsic mode decomposed by the mode demultiplexer; the polarization CBC chip is connected with the other end of the single-mode optical fiber array; the driving control module is connected with the polarization CBC chip; the polarization multiplexing optical communication digital coherent receiver (Rx) is connected with the polarization CBC chip through a single-mode optical fiber; through the arrangement of the polarization CBC chip, the compatibility of a polarization multiplexing technology and a mode multiplexing coherent beam combination technology is realized, the problem of polarization dimension information loss or strong crosstalk caused by the use of a polarization state rotator (PSR) and a polarization maintaining optical fiber in the prior art is solved, modulation information of two orthogonal polarization dimensions is completely reserved, the communication bandwidth is improved, and the communication efficiency is improved. And the communication efficiency is greatly improved.

The utility model discloses an on-chip integrated wavelength division multiplexer and a photon integrated circuit chip, the wavelength division multiplexer comprises a polarization compatible flat-topped wavelength division multiplexing structure, the flat-topped wavelength division multiplexing structure is provided with a first input waveguide group, a second input waveguide group and an output waveguide, the flat-topped wavelength division multiplexing structure performs odd-even grouping on the configured central wavelengths of the first input waveguide group and the second input waveguide group, and optical signals in different groups are respectively input into the wavelength division multiplexer in different polarization states; and on the basis of a single polarization compatible flat-topped wavelength division multiplexing structure, two groups of multi-path optical signals with different wavelengths in different polarization states are multiplexed into one path of multi-wavelength-polarization multiplexing light, so that signal crosstalk between adjacent channels is reduced, the structural complexity and size of the wavelength division multiplexer are simplified, and the integration level of a photon integrated circuit chip is improved.

The present application relates to a polarization multiplexing structured light generating device and a preparation method thereof, belonging to the technical field of optical devices. The structured light generating device includes a light source and a metasurface for controlling the polarization of the outgoing light. The metasurface includes a substrate and a metasurface unit placed on the substrate. The phase distribution of the metasurface under different incident polarizations is changed by the type, size and arrangement of the microstructure, and the phase change range is within 0-2π. The present application realizes two different beam control functions, namely, dot matrix and flood light, by adjusting the polarization state of the outgoing light from the light source and utilizing the different responses of the metasurface to the polarization of the incident light.

The invention relates to the technical field of optical communication, and discloses a multi-dimensional and multi-phase-based 50G PON signal noise compensation method, which comprises the following steps: S1, generating a mixed signal, including superposing a multi-phase orthogonal pilot signal into a data signal time domain at a transmitting end according to a preset proportion lower than the power of a data signal; and S2, transmitting the mixed signal in a polarization multiplexing mode, wherein the polarization multiplexing adopts double-channel parallel transmission of an X polarization state and a Y polarization state. Multi-phase orthogonal pilot signals are superposed to a data signal time domain in a low-power proportion at a transmitting end, polarization multiplexing dual-channel transmission is adopted, a narrow-band filter is utilized at a receiving end to separate pilots and calculate channel damage parameters, and a finite impulse response filter is configured to perform linear equalization compensation. And the simplified Kalman filtering algorithm is combined to estimate the phase noise and correct the phase, so that collaborative suppression of the linear channel damage and the phase noise in the 50G PON signal is facilitated.

The invention discloses a polarization rotation beam splitter structure based on a lithium niobate film, belongs to the technical field of optical waveguides, and particularly relates to an integrated optical device for realizing polarization rotation and beam splitting of optical signals. The main structure is two linear tapered waveguides and an asymmetric coupler, the structure utilizes the excellent electro-optical characteristics of a lithium niobate film, and through the design of the linear tapered waveguides and an asymmetric directional coupling unit, when light is transmitted along the tapered waveguides which are gradually increased, due to the hybridization between modes, the light transmission efficiency is improved, and the light transmission efficiency is improved. The TM0 mode of narrow band import emission is gradually converted into the high-order TE1 mode, the high-order TE1 mode is coupled through the asymmetric coupler and converted into the TE0 mode to be output, efficient polarization rotation and beam splitting functions between the TM mode and the TE mode are achieved, and potential application prospects are achieved. The polarization rotation beam splitter not only realizes simplification of a device structure, is expected to be applied to efficient polarization multiplexing and polarization modulation, but also provides flexibility for manufacturing a large-scale optical switch array and an optical interconnection network.

The invention relates to a broadband polarization multiplexing imaging metasurface which combines a newest machine learning algorithm and an advanced optical simulation technology and aims at achieving broadband high-definition and polarization multiplexing imaging effects. Meanwhile, the complete process of the metasurface from concept proposing to final design is elaborated, and by accurately developing machine learning model training and performing optical simulation verification, the polarization multiplexing far-field imaging metasurface in the same wavelength range is heart-shaped under x polarization and round under y polarization, and the metasurface is in the shape of the heart. It is ensured that the metasurface has excellent imaging performance in different polarization states. The innovative design not only improves the imaging quality, but also expands the application potential in various optical systems.

The invention discloses a wavelength and polarization multiplexing super-structure lens construction method based on a double-layer geometric phase, and provides a double-layer geometric phase super-structure surface theoretical model by using a super-structure based on an artificial micro-nano structure, and designs a lens structure of which two working wavelengths and two polarization modes can be regulated and controlled at will by using the model. The working principle of the double-layer geometric phase super-structure lens is elaborated; secondly, optimizing and screening unit structures of the single-layer super-structure lens, establishing a unit structure database, and designing a double-layer super-unit structure on the basis of the unit structures; and finally, a double-layer super-structure lens is constructed by using a super-unit structure, so that the double-layer super-structure lens works at two wavelengths and two polarization states, and the adjustable multifunctional characteristics of dual-wavelength switchability and polarization sensitivity are realized. The method has important application prospects in the fields of dual-wavelength polarization sensitive imaging, optical tomography, sensing, new energy automobile display systems, AR / MR display and the like.

A chromatic dispersion compensation filter is configured to multiply each of a real component and an imaginary component of each of a first polarization and a second polarization of a polarization-multiplexed optical signal by a filter coefficient that compensates for chromatic dispersion. An adaptive equalizer is configured to multiply input signals and their phase conjugates by a complex impulse response and add the signals multiplied by the complex impulse response. The adaptive equalizer is configured to perform, for each polarization, phase rotation for carrier phase compensation including a frequency offset and rotation reverse to the phase rotation and add, for each polarization, the signals subjected to the phase rotation and the signals subjected to the rotation reverse to the phase rotation.

The invention discloses a polarization beam splitter based on a silicon dioxide optical waveguide, and belongs to the technical field of photon integration. The optical fiber sequentially consists of a substrate, a lower cladding, a core layer waveguide and an upper cladding, wherein the core layer waveguide is coated by the upper cladding; the lower cladding layer and the upper cladding layer are made of silicon dioxide, the core layer waveguides have the same height, are made of germanium-doped silicon dioxide, and are composed of a first 1 * 1 MZI waveguide Core1, a middle straight waveguide Core2 and a second 1 * 1 MZI waveguide Core3; when the waveguide spacing in the middle area of the core layer waveguide is close enough, the core layer waveguide can be regarded as a grating-like structure, so that the average effective refractive indexes of a TE mode and a TM mode in the area are different, coupling and multi-mode interference of light modes are generated at the same time, and after a certain length, the TE mode and the TM mode generate a phase difference, so that the interference of the TE mode and the TM mode is reduced. And finally, carrying out polarization separation and respectively outputting from two ports. The polarization multiplexing technology of a low-refractive-index-difference platform is achieved, or unwanted polarization states are filtered out in a polarization-sensitive device.

The invention provides a reference light polarization multiplexing TF-QKD device and a coding method, and relates to the technical field of quantum communication. A light source emitted by a single-wavelength laser is subjected to time division multiplexing modulation through a phase modulator, an intensity modulator and a polarization modulator to obtain a strong phase reference light pulse, a weak phase reference light pulse and a quantum signal light pulse; after being attenuated by the optical attenuator, the signals are sent to a detection end through an optical fiber line; after light pulses of an Alice end and a Bob end received by a detection end pass through respective links, the light pulses are modulated by polarization controllers of respective light paths and then enter a light interference module for interference, the interfered light is divided into two beams, and the two beams respectively enter a first polarization beam splitter and a second polarization beam splitter for polarization; the light split by each polarization beam splitter respectively enters two avalanche detectors for detection, and the detection result is sent to a synchronous counter to ensure that the pulse arrival time of the Alice end is consistent with the pulse arrival time of the Bob end.

The invention discloses a dual-state six-channel polarization multiplexing metasurface design method based on a phase change material. The method comprises the following steps: designing a structural unit based on the phase change material; a double-state six-channel polarization multiplexing metasurface is constructed by using the designed structural unit; the geometric structures and the orientation angles of the structural units are optimized by adopting a screening algorithm, and the optimized double-state six-channel polarization multiplexing metasurface can record six kinds of irrelevant phase information into the same double-state six-channel polarization multiplexing metasurface. The method is based on the metasurface Jones matrix regulation and control theory, comprehensively utilizes the geometric phase and the transmission / resonance phase of the structural unit, is suitable for most types of metasurface unit structures, has wide applicability, can be applied to the fields of metasurface optical encryption, multifunctional wavefront regulation and control and the like, and has important practical value.

The invention provides a polarization multiplexing metasurface-based depolarization holographic method, which comprises the following steps of: describing a polarization state of light by using Jones calculation, and defining a propagation model of a wave; the pixel pitch of the metasurface and the height of the nanorod are determined, and a function between the length and width (l, w) of the nanorod and the modulation phase is obtained; a strict coupling wave analysis RCWA method is used, and electromagnetic response of the nanostructure is simulated under local period approximate LPA; fitting the libraries of phi xx and phi yy through a linear quadratic polynomial at each wavelength so as to represent a Jones matrix of the metasurface; introducing a noise function fnoise, applying the noise function fnoise to the metasurface, and calculating the complex amplitude of the metasurface by using an agent model; and establishing a joint optimization process, optimizing the metasurface geometric diagram and the SLM phase diagram, generating a focal length stacking hologram of the target image data set, and performing verification by using a CITL calibration model. According to the method, the image quality can be improved.

According to the indirect image encryption method based on the polarization multiplexing metasurface, the used phase gradient metasurface is composed of nanometer bricks with singular point characteristics and mirror image structures of the nanometer bricks, when left-hand circularly polarized light and right-hand circularly polarized light are incident, the corresponding structures of the nanometer bricks play a role respectively, two holograms are constructed in a far field, and polarization multiplexing is achieved; on the basis that two structures are arranged in the column direction to form a super unit, when x-ray polarized light is incident, light is subjected to non-abnormal reflection through the generalized Snell law, required RCP and LCP are filtered out, and emergent light is superposed to generate vector light; performing condition limitation on the azimuth angle of the vector light through a simulated annealing algorithm to obtain two encrypted patterns; the encrypted pattern needs to be obtained by analyzing the polarization of the emergent light to obtain a corresponding Stokes parameter and then constructing a decryption function related to the Stokes parameter for calculation and analysis; therefore, the metasurface for realizing polarization multiplexing and indirect encryption functions of incident light in different polarization states is constructed.

The invention relates to the technical field of optical fiber communication, and particularly discloses a polarization demultiplexing method and system based on rotation angle and phase delay estimation of a Stokes space, and the method comprises the steps: obtaining two polarization multiplexing signals which are transmitted through an optical fiber and are transmitted on the same wavelength, dividing the two paths of polarization multiplexing signals into a first optical signal and a second optical signal according to a preset proportion; based on the first optical signal, calculating a rotation angle and phase delay by using a digital signal processing algorithm, and obtaining a corresponding control voltage according to the calculated rotation angle and phase delay; adjusting an arranged polarization control panel by using the obtained control voltage, so that two paths of polarization multiplexing signals of a second optical signal part are separated after the second optical signal passes through the polarization control panel; and demodulating the second optical signal passing through the polarization control board to obtain two independent paths of output optical signals which are respectively demodulated by two direct detection receivers.

Disclosed in the present application are an on-chip integrated wavelength division multiplexer and a photonic integrated circuit chip. The wavelength division multiplexer comprises a polarization-insensitive flat-top wavelength division multiplexing structure, wherein the flat-top wavelength division multiplexing structure has a first input waveguide group, a second input waveguide group and an output waveguide. In the flat-top wavelength division multiplexing structure, odd-even grouping is performed on central wavelengths configured for the first input waveguide group and the second input waveguide group, optical signals of different groups are respectively input into the wavelength division multiplexer in different polarization states, and on the basis of a single polarization-insensitive flat-top wavelength division multiplexing structure, two groups of multiple optical signals of different wavelengths and in different polarization states are multiplexed into one multi-wavelength and polarization multiplexed light, thereby reducing signal crosstalk between adjacent channels, simplifying the structural complexity of the wavelength division multiplexer, reducing the size of the wavelength division multiplexer, and thus facilitating an improvement in the integration level of the photonic integrated circuit chip.

The invention belongs to the technical field of visible light wireless laser communication, and particularly relates to a dual-polarization dual-aperture multi-wavelength visible light wireless laser communication system. The system comprises a digital signal processing module, two groups of five-wavelength laser transmitting modules and an in-phase or anti-phase transmitting module based on polarization multiplexing at a transmitting end, and a dual-aperture receiving module, a maximum ratio merging or differential processing module and a receiving end digital signal processing module at a receiving end, according to the invention, complementary dual-polarization in-phase transmission of damages in horizontal and vertical polarization directions and dual-polarization differential transmission of common-mode interference suppression can be realized. For dual-polarization in-phase transmission, the two groups of lasers modulate the same signals, and a receiving end adopts a maximum-ratio merging algorithm to perform merging; for dual-polarization differential transmission, two groups of lasers modulate inverted signals, and receiving of two apertures of a receiving end is differentiated. According to the invention, the reliability and robustness of communication can be greatly improved, and higher-rate and larger-capacity communication can be realized.

The invention discloses a five-dimensional coherent detection method and a receiver. Based on a dual-polarization 90-degree optical mixer, four pairs of balanced photoelectric detectors, a single-ended photoelectric detector and a digital domain optical field reconstruction module, complex optical field reconstruction of single-sideband or double-sideband modulation local oscillation light is realized, and beat frequency damage between local oscillation and signals is eliminated; and simultaneous coherent detection of polarization multiplexing signal light and single-sideband or double-sideband modulation local oscillation light is supported. Only one path of single-end photoelectric detector needs to be additionally arranged, extra modulation information is transmitted through local oscillation light, and the dimension of a received signal is linearly expanded to five dimensions with the lowest hardware complexity. According to the invention, the linear extension of the receiving dimension is realized with the lowest hardware complexity.

The invention provides a signal processing method and system in continuous variable quantum key distribution, and relates to the technical field of communication. The method comprises the following steps: carrying out up-conversion operation on two double-sideband quadrature phase shift keying signals, and respectively converting the two double-sideband quadrature phase shift keying signals into a first center frequency and a second center frequency to form a first quantum signal in an X polarization direction and a first quantum signal in a Y polarization direction; adding a first pilot signal in the X polarization direction to the first quantum signal in the X polarization direction to obtain a first optical signal in the X polarization direction; adding a first pilot signal in the Y polarization direction to the first quantum signal in the Y polarization direction to obtain a first optical signal in the Y polarization direction; combining the first optical signal in the X polarization direction and the first optical signal in the Y polarization direction into a polarization multiplexing signal by using a polarization coupler; and transmitting the polarization multiplexing signal to a receiving end through a quantum channel. According to the embodiment of the invention, the security key rate of continuous variable quantum key distribution can be improved.

The application discloses a 3D printing multi-sector multifunctional metasurface and a design method thereof. The multi-sector multifunctional metasurface is designed based on five polarization multiplexing multifunctional metasurfaces with different phase control means, then the five metasurfaces are respectively faced to five different directions in space and integrated by using a 3D printing technology, and a multi-sector metasurface is formed. Finally, the designed multi-sector metasurface can integrate different electromagnetic functions in five directions in a 3D space. The application designs a polarization multi-sector metasurface based on the 3D printing technology. The polarization multi-sector metasurface can integrate electromagnetic functions of non-common polarization waves on a single device, and can complete wave front control in multiple directions in space, so that the electromagnetic wave control range is expanded from only transmission and reflection to multi-direction control, and the information capacity of the electromagnetic device and the space utilization rate of the wave front control are greatly improved.

The invention discloses an inter-satellite laser communication transmitting system for signal light polarization multiplexing, and relates to the technical field of satellite laser communication. Comprising a coarse tracking adjustment mechanism, a fine tracking adjustment mechanism, a 1 / 4 wave plate, a spectrum optical splitter, an advance angle adjustment mechanism, a transmitting beacon signal laser system, a receiving signal beacon detection system, a wave plate and a pyramid. The transmitting beacon signal laser system comprises a polarization optical splitter I, a signal collimator, a linear polarization signal laser, a half-wave plate, a signal collimator and a linear polarization beacon laser; the received signal beacon detection system comprises a polarization beam splitter II, a beacon detector, a reflector and a signal detector; according to the inter-satellite laser communication transmitting system for signal light polarization multiplexing, the wavelengths and the linear polarization states of the transmitted signal light and the beacon light are the same, the polarization states are modulated, the effect of signal light polarization multiplexing is achieved, separation of the signal light and the beacon light is achieved, the complexity of the system is effectively reduced, and meanwhile the reliability and efficiency of link establishment are improved.

A pump light generation unit of an optical amplifier pumping device outputs pump light with a single wavelength or a plurality of wavelengths from a plurality of output ports. A pump light multiplexing unit polarization-multiplexes or wavelength-multiplexes the plurality of pieces of pump light which has been output from the pump light generation unit. A polarization scrambler collectively polarization-scrambles the polarization-multiplexed or wavelength-multiplexed pump light which has been output from the pump light multiplexing unit and outputs the polarization-scrambled pump light to an optical waveguide for pump light. The optical waveguide for pump light inputs the pump light which has been polarization-multiplexed or wavelength-multiplexed by the pump light multiplexing unit to the pump light superimposition unit. A pump light superimposition unit multiplexes the polarization-multiplexed or wavelength-multiplexed pump light and signal light. A pump light output port superimposes the pump light on the signal light by outputting the pump light from the pump light superimposition unit to the gain medium so that the pump light propagates in the same direction as the signal light.

The invention discloses a compensation method and device with robustness under a polarization effect, equipment and a storage medium, belongs to the technical field of communication, and solves the problem that the robustness of a communication system is affected under the existing factors such as rapid polarization state disturbance. A compensation method with robustness under a polarization effect comprises the following steps that S1, a transmitting end processing module generates a polarization multiplexing signal, and a pair of pilot frequencies is inserted in each of two polarization directions of the polarization multiplexing signal to obtain a transmitting end signal; s2, sending the sending end signal to a receiving end digital processing module through a link with a polarization effect, extracting a damage matrix at an insertion position by the receiving end digital processing module according to the pilot frequency, and calculating differential group delay and polarization loss according to a channel matrix, and constructing a damage compensation matrix and completing compensation of the link with the polarization effect. The method provided by the invention has high robustness under the condition that polarization rotation and polarization mode dispersion are damaged in a polarization state.

The present invention discloses a chip architecture for optical communications, including a modulated transmitter and a balanced detector. The modulated transmitter is used to modulate a signal light source and transmit it along a signal optical path X and a reference optical path Y, respectively. The modulated transmitter is provided with a polarization combiner for polarization combining light II and light I that has undergone IQ modulation. In the balanced detector, a polarization beam splitter is used to receive and decompose the combined light. A local oscillator light source is used to perform 90° mixing with the decomposed light and transmit the mixing results to a photodetector array. The photodetector array is used to perform photoelectric conversion on the mixing results and transmit them to a coherent processor for coherent analysis. The present invention adopts a polarization multiplexing route architecture to design the chip, so that local oscillator light amplification can further reduce the bit error rate of the transmitted signal. The present invention also utilizes the second-order correlation of the light field to complete signal detection, while eliminating the effects of noise and low power introduced during local oscillator light amplification on signal detection, thereby broadening the application scenarios.

The present invention discloses a terahertz circular polarization multiplexing long focal depth polarization state longitudinal evolution meta-structure device design method and meta-structure device, which belongs to the field of optical devices, and includes the following steps: S1, constructing a linear transmission Jones matrix; S2, setting a screening rule for a super unit structure based on the linear transmission Jones matrix; S3, designing the phase of the metasurface, the initial phase of the light field, and the initial surface phase distribution of the light field; S4, using all-silicon dielectric materials to construct a metasurface unit according to the designed phase of the metasurface, the initial phase of the light field, and the initial surface phase distribution of the light field; S5, based on the screening rule, screening the metasurface unit composition with a phase gradient of π / 8 and a unit library with full coverage from 0 to 2π; S6, based on the unit library, using an automatic layout algorithm to construct a metasurface structure. The present invention adopts the above-mentioned terahertz circular polarization multiplexing long focal depth polarization state longitudinal evolution meta-structure device design method and meta-structure device, and realizes that under the incidence of linear polarized terahertz light, the metasurface focuses the left and right hand components at different focal depths respectively, and realizes the generation of different polarization states through the principle of polarization superposition.