48 results about "Orbital angular momentum multiplexing" patented technology

The invention relates to a multimodal orbital angular momentum multiplexing system and method. The system comprises a transmitting device and a receiving device which are in mutual communication connection. The transmitting device comprises a bit level processing module, a constellation mapping module, an orbital angular momentum modulation module, a digital domain orbital angular momentum multimodal multiplexing module, a DAC module, an upper conversion module and a ring array transmitting antenna. The receiving device comprises a ring array receiving antenna, a down conversion module, an ADC module, a digital domain orbital angular momentum demodulation and demultiplexing module and a detection decoding module. According to the system and the method, a vortex electromagnetic wave multimodal OAM (Orbital Angular Momentum) multiplexing communication technology of which physical feature is clearly different from that of a traditional plane wave is realized; the spectral efficiency and the transmission rate are multiplied; and the improvement space and potential of the modal multiplexing quantity is further expanded. The system and the method can be applied to the multimodal OAM multiplexing communication system in a microwave or millimeter wave band.

The invention provides a spin angular momentum-orbital angular momentum hybrid modulation quantum secret key distribution method and system. The spin angular momentum-orbital angular momentum hybrid modulation quantum secret key distribution system comprises a hybrid spin angular momentum-orbital angular momentum generation unit, a spin angular momentum modulation unit, an orbital angular momentum modulation unit, and a coincidence measurement decoding unit. The hybrid spin angular momentum-orbital angular momentum generation unit is used for generating spin angular momentum-orbital angular momentum hybrid entanglement quantum states. The spin angular momentum modulation unit is used for conducting phase position deflection modulation on the spin angular momentum of signal photons. The orbital angular momentum modulation unit is used for conducting phase position deflection modulation on the orbital angular momentum of idle photons and loading coded information. The coincidence measurement decoding unit is used for conducting coincidence measurement on the signal photons and the idle photons to decode quantum bit information. The safety of the spin angular momentum-orbital angular momentum hybrid modulation quantum secret key distribution system is improved, large-capacity quantum coding is achieved, and the quantum secret key distribution system is efficient in coding, simple in structure and high in safety.

The invention discloses a multi-user orbital angular momentum multiplexing network system, comprising an Alice control terminal, an S-D type orbital angular momentum multiplexing unit and a Bob user terminal, wherein the Alice control terminal comprises a laser source, a polarization controller, an attenuator, a first non-equal arm M-Z interferometer and an orbital angular momentum multiplexing unit; the orbital angular momentum demultiplexing unit comprises a Dammam grating, a second collimator and a single-mode fiber; the Bob user terminal comprises N Bob users; the laser source generates a light signal, the light signal is transmitted to the first non-equal arm M-Z interferometer after entering the polarization controller and the attenuator and is sequentially transmitted to the orbital angular momentum multiplexing unit and the orbital angular momentum demultiplexing unit; and finally, the light signal enters the Bob users for detection. The multi-user orbital angular momentum multiplexing network system disclosed by the invention is used for achieving one-to-many communication of quantum network communication of a free space, individual users are relatively independent, and the user number can be expanded with the increase of the orbital angular momentum multiplexing, so that the expandability is good.

The invention discloses a signal transmission method based on acoustic orbital angular momentum multiplexing. The method comprises the following steps that a plurality of mini loudspeakers form a loudspeaker array, sound waves of acoustic orbital angular momentums of different orders are generated as independent channels, wherein the sound waves of the acoustic orbital angular momentums of the different orders are different channels, and each group of binary data streams formed by 0-1 are encoded on amplitudes and phases of the sound waves of one group of channels as signal sources; and (2) the signal source of an input end transmits a sound wave signal of the signal source to demodulation metasurfaces which are arranged in sequence through a transmission pipe, and the sound wave signal detected by a microphone is arranged at the back of each demodulation metasurface and is the original input data stream. According to the signal transmission method based on acoustic orbital angular momentum multiplexing, the signals can be simultaneously loaded to sound pressure values of vortex fields of different orders to carry out synchronous transmission, and meanwhile, the designed demodulation metasurfaces can be utilized to realize high-efficiency separation and detection of different pieces of information.

The invention discloses an orbital angular momentum (OAM) multiplexing transmission system based on phase surface relaying. The OAM multiplexing transmission system comprises a signal transmitting end, a signal receiving end and a central receiver, wherein the signal transmitting end is used for collecting user data, modulating the user data into OAM electromagnetic waves of a plurality of modes,and transmitting the OAM electromagnetic waves to the signal receiving end; the signal receiving end comprises a plurality of relay repeaters which are distributed on a circular ring covered by a mainlobe; each relay repeater forwards received signals at different locations on a phase plane circular ring; the relay repeaters are independent of each other, and the number of the relay repeaters isno less than the mode number of the OAM electromagnetic waves; the signals are forwarded to the central receiver in a wireless or wired way; the central receiver comprises a second receiving and transmitting antenna for receiving the signals relayed and forwarded by the plurality of relay repeaters, a phase plane correction module for carrying on phase plane correction on the distributed transmitted signals, and a demodulation module for demodulating the signals being subjected to phase plane correction. By adopting the system, electromagnetic wave orbital angular momentum transmission of longdistance, high capacity and high spectral efficiency can be realized.

The invention discloses an orbital angular momentum (OAM) coherent demultiplexing device and a separation detection method. The device comprises a beam splitter for carrying out beam splitting on incident beams, a reflector for adjusting the light propagation direction and realizing an odd number of times of light reflection, a liquid crystal spatial light modulator for converting vortex beams with specific topological load to fundamental-mode Gaussian beams, a coherent separation unit for realizing separation between an OAM channel with certain specific topological load and other OAM channels, a phase shifter for realizing phase shift pi of beams, a photoelectric detector for realizing photoelectric conversion, and a differential circuit for subtraction operation on current. The device of the invention is used for realizing OAM coherent separation detection. The novel device provided by the invention can enhance the detection performance of the existing free-space optical orbital angular momentum multiplexing communication system and the transmission distance, and an important application prospect is realized in fields of optical communication in a vortex field and information processing.

The invention provides an underwater acoustic communication method and system based on an orbital angular momentum multiplexing technology. The method comprises the following steps of applying an excitation signal to each array element in a sound source array; modulating the excitation signal in each sub-channel in order to obtain a modulated array element driving signal carrying baseband digitalinformation in each sub-channel; carrying out channel multiplexing on the modulated array element driving signal carrying the baseband digital information, and driving the sound source array to generate an OAM spiral sound field after channel multiplexing; receiving an OAM spiral sound field signal, and carrying demultiplexing processing on the received signal in order to obtain sub-channel information loaded on each independent OAM topological charge; and demodulating the information after demultiplexing in order to obtain an original digital baseband signal. According to the method, the channel capacity and the transmission rate of communication transmission based on underwater sound waves are greatly improved.

The invention discloses a quantum key distribution network system and method based on orbital angular momentum multiplexing. The system comprises an Alice control side, an orbital angular momentum mode division multiplexing unit and a Bob user side. The Alice control side comprises a signal modulation unit and an orbital angular momentum multiplexing unit. The orbital angular momentum mode division multiplexing unit comprises a Galileo telescope assembly and an orbital angular momentum separation device. The Bob user side comprises N Bob users. Each Bob user comprises a polarization controllerand a detection device. A light signal generated by the signal modulation unit enters the orbital angular momentum multiplexing unit, the Galileo telescope assembly and the orbital angular momentum separation device in sequence, then is transmitted to the polarization controller of the corresponding Bob user side and finally enters the detection device for detection. According to the system and method, one-to-many communication of quantum network communication is realized, each user is relatively independent, the number of the users can be increased as the orbital angular momentum multiplexing is increased, and the system and the method have high expandability and relatively high practicability.

The invention belongs to the technical field of communication, in particular to a large-capacity optical fiber-rail angular momentum wave fusion system. The system is implemented by the following steps that: synthesis of two paths of light baseband signals or light microwave signals is realized by a wavelength division multiplexer at a transmitting end, then optical fiber transmission is entered,and a wavelength division multiplexed signal is demultiplexed with an array waveguide; the demultiplexed light signal is converted into an electric baseband signal or an electric microwave signal through a photelectric detector, and two paths of electric signals are converted into a rail angular momentum multiplexed signal to be transmitted through a single rail angular momentum antenna after up-conversion is realized with an electric frequency mixer; and a rail angular momentum antenna at a receiving end demultiplexes a received signal, and a baseband signal is recovered with an electric downconverter and a low-pass filter. Through adoption of the large-capacity optical fiber-rail angular momentum wave fusion system, the use of a plurality of antennas is avoided, and the system complexity is lowered. Moreover, wavelength division multiplexing and rail angular momentum space multiplexing are combined, so that the communication capacity and spectrum efficiency of the system are increased greatly.

The invention provides a detection system for identifying OAM beam topological charge based on signal crosstalk distribution characteristics. The system comprises an OAM multiplexing module, first andsecond optical antenna modules, an OAM demultiplexing module and an OAM beam topology charge detection module. The OAM multiplexing module carries out orbital angular momentum multiplexing on a vortex beam. The first optical antenna module transmits a vortex beam signal which passes through the OAM multiplexing module into an optical communication channel. The second optical antenna module receives a beam which passes through the optical communication channel and transmits the beam to the OAM demultiplexing module. The OAM demultiplexing module decomposes a received light signal into a set ofOAM modes, converts the signal into a crosstalk distributed electrical signal and then inputs the crosstalk distributed electrical signal into the OAM beam topology charge detection module. The OAM beam topology charge detection module analyzes the inputted data to obtain the topology charge of the vortex beam. According to the detection system, the characteristics of the crosstalk distribution is used, the topological charge information contained in the crosstalk distribution is fully utilized, thus the vortex beam topology charge detection has high accuracy and a fast rate, and the high-rate information transmission is realized.

The invention discloses a negative curvature terahertz optical fiber supporting 52 orbital angular momentum modes. The negative curvature terahertz optical fiber comprises a polymer coating layer, an outer oval cladding tube region, an annular cladding tube, an inner oval cladding tube region and a fiber core region, wherein the outer elliptical cladding tube region consists of 12 polymer unit structures which are annularly arranged; the inner elliptical cladding tube region consists of 18 polymer unit structures which are annularly arranged; and the inner elliptical cladding unit structure and the outer elliptical cladding unit structure are respectively connected with the annular cladding tube unit structure to form a cladding tube region of the optical fiber structure. According to the optical fiber, an orbital angular momentum (OAM) mode with relatively high purity can be generated, and a plurality of channels can be formed during communication in an annular region. The orbital angular momentum multiplexing technology is applied to terahertz wave communication, the channel capacity of a communication system is improved, meanwhile, the information has higher safety in the transmission process, and the terahertz wave communication system has the advantages of being low in loss, large in communication capacity and the like.

The invention discloses a partial reception method for an orbital angular momentum mode demultiplexing. A partial reception bore is 1/n of the whole bore circumference needed by complete reception, a plurality of orbital angular momentum multiplexing wave beams comprising a group of orbital angular momentum topological charges li meeting a certain rule are selected, the topological charges li meet li=l+nm, the l refers to an optional orbital angular momentum topological charge, the m is an integer, the n is an integer larger than or equal to 2, the orbital angular momentum multiplexing wave beams are mutually orthogonal, the 1/n partial reception bore is used for receiving at a receiving end, and low-crosstalk orbital angular momentum mode demultiplexing can be realized.

The invention discloses a broadband optical orbital angular momentum multiplexing and demultiplexing method and device and a storage medium. The method comprises the steps: transmitting signal light through a plurality of independent polarization and independent wavelength light sources, enabling the signal light to enter a metasurface grating from different angles, generating OAM light beams with different topological charges, synthesizing the OAM light beams into a coaxial light beam in a 0-level diffraction direction, and enabling the coaxial light beam to be emitted out, thereby realizing the OAM multiplexing; the coaxial light beam is incident on the metasurface grating, the OAM light beam is reduced into Gaussian light at different diffraction orders, signal light is obtained after small hole filtering, OAM demultiplexing is achieved, and the complexity of the system is reduced. The problem of complexity of a broadband optical orbital angular momentum multiplexing and demultiplexing system in the prior art is solved.

The invention provides an orbital angular momentum multiplexing channel conversion and data exchange method and device. The method comprises the steps: inputting an OAM seed light beam and a Gaussian type pump light beam from the two sides of a nonlinear medium respectively, so that the OAM seed light beam and the pump light beam generate a non-collinear SBA effect in the nonlinear medium, and a coherent phonon field with the same topological charge as the OAM seed light beam is excited; enabling the first OAM channel light beam loaded with the first coded data and the second OAM channel light beam loaded with the second coded data to form an OAM multiplexing light beam on one side of the Gaussian pump light beam; and enabling the OAM multiplexing light beam and the OAM seed light beam to collinearly enter into the nonlinear medium and to be subjected to BAPA interaction with the coherent phonon field so as to obtain an OAM channel light beam after channel conversion and data exchange. According to the invention, the data exchange of the OAM state of the two channels to be exchanged is realized through the BAPA process.