48 results about "Orbital angular momentum multiplexing" patented technology

The invention provides the orbital angular momentum generating device and method of a polarization modulation orbital angular momentum. The device comprises a Gaussian light source module, a first orbital angular momentum modulation module, a second orbital angular momentum modulation module and a reuse module. When the device works, the Gaussian light source module generates the Gaussian light beam of any polarization states and the light beam enters into the reuse module; the reuse module decomposes the Gaussian light beam into two polarization components whose polarization directions are horizontal and vertical, and the components are introduced into the first or second orbital angular momentum modulation module; the modulation module carries out polarization-independent orbital angularmomentum modulation on the two components, and the two modulated optical components are returned to the reuse module; and the reuse module superposes the two optical components, and finally outputs an orbital angular momentum state or superposition state. The structure is compact, manufacturing cost is low, a required device and technology are mature, the orbital angular momentum state and the superposition state of any topological charge number can be generated at a high speed, and a rate can reach the order of MHz.

The invention relates to a high-capacity orbital angular momentum hybrid multiplexing communication method and a testing method thereof. The test method includes: synthesizing multiple vortex optical signals generated by a Gaussian beam through orbital angular momentum multiplexing, polarization division multiplexing and frequency division multiplexing in sequence; , the atmospheric turbulence is simulated by a multi-layer phase screen; and parameters of the communication are measured. Compared with the traditional technology, the communication method provided by the invention can further improve the communication capacity and rate.

The invention discloses a multi-channel orbital angular momentum multiplexing nonlinear holographic device. The light source is a near-infrared laser. The beam emitted by the near-infrared laser passes through a linear polarizer and is separated into a beam I and a beam II by a beam splitter I. The beam After I is reflected by the spatial light modulator I, it passes through the beam splitter I, lens I, hole, mirror, and lens II in sequence, and merges with the beam II at the polarizing beam splitter; a light baffle is placed on one side of the beam splitter II, and the beam II The light beam separated by the beam splitter II is reflected by the spatial light modulator II, then passes through the beam splitter II, lens III, half-wave plate, and lens IV in sequence, and merges with the beam I at the polarizing beam splitter; the combined beam passes through KTP crystal, lens V, the fundamental wave and the second harmonic are separated by the dichroic mirror, and finally recorded by the CCD camera respectively. The invention widens the number of channels on each optical frequency, has high signal-to-noise ratio and good imaging effect.

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 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 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 relates to the technical field of optoelectronic components and devices, and proposes a VCSEL-based orbital angular momentum multiplexing device, including a vertical cavity surface emitting laser, a silicon nitride phase layer, a metal shielding layer, a P-face electrode and an N-face electrode; On the cavity surface emitting laser, a cylinder, a first outer ring and a second outer ring structure are sequentially etched from the inside to the outside with the center point as the center; the silicon nitride phase layer is arranged on the upper surface of the cylindrical structure, accounting for half of the upper surface of the cylinder One area; the metal shielding layer is arranged on the upper surface of the first outer ring and the upper surface of the second outer ring and etched into a metal grating structure; the P-face electrode and the N-face electrode are arranged on the vertical cavity surface emitting laser. The present invention also proposes a preparation method of the multiplexing device, and the multiplexing device can realize coaxial independent modulation of high-purity 1st, 2nd, and 3rd-order OAM beams, and realize coaxial integration of OAM beams, and the multiplexing device The production cost is low, and the preparation process is simple.

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 device and a method for millimeter-wave orbital angular momentum communication based on a radio over fiber technology. The device comprises an eight-channel optical millimeter-wave phase modulation link, an annular transmitting antenna array and an annular receiving antenna array. The millimeter-wave communication capacity and the spectrum utilization ratio are greatly improved by taking the orbital angular momentum as a new information bearing dimension. The millimeter-wave orbital angular momentum modulation is moved from the electric domain to the optical domain by using the radio over fiber technology, thereby realizing high-speed modulation for the millimeter-wave orbital angular momentum. Millimeter-wave orbital angular momentum signals are radiated to the free space and received and demodulated by using the antenna arrays. The millimeter-wave orbital angular momentum communication system disclosed by the invention breaks through defects of low speed, complex demodulation, low efficiency and the like of traditional orbital angular momentum modulation, has the advantages of radio over fiber communication, can realize long-distance transmission of millimeter-wave orbital angular momentum information by using optical fibers, can expand a traditional wireless demodulation technology so as to realize demodulation for the millimeter-wave orbital angular momentum, and ensures the convenience of the system.