A system for electromagnetic communication with a vortex beam concurrently conveys multiple topological charges of orbital angular momentum. The system includes a source, at least one vortex-sensing diffraction grating, and an array of photodetectors. The source generates the vortex beam concurrently conveying a respective number of selected topological charges during each of the time intervals. The selected topological charges for each time interval are selected from a set of available topological charges. The selected topological charges for each time interval encode a symbol of data. The vortex-sensing diffraction grating combines a vortex phase pattern and a linear phase pattern. The vortex sensing diffraction grating produces a diffraction pattern from diffracting the vortex beam received from the source. The array of photodetectors detects portions of the diffraction pattern and from the detected portions recovers the selected topological charges encoding the symbol of each time interval.

Methods and devices to split electromagnetic waves across broad bandwidths in correspondence with orbital angular momentum states combined with orthogonal polarization states are disclosed. The described methods can be used in fiber communication and imaging systems. The devices include three-dimensional (3D) scattering structures that can be using existing CMOS processes and direct write lithography techniques. Performance metrics based on the intensity and contrast of the split electromagnetic waves are also disclosed.

Provided is a method and device for receiving OAM information blocks. The method includes: determining a reference position and a delivery cycle value of reception of the OAM information block; determining an expected reception position of a next OAM information block according to the reference position and the delivery cycle value, determining an effective reception range according to the expected reception position, and extracting an OAM information block in a client service code block stream within the effective reception range; and synchronizing a sequence relationship of the OAM information blocks according to the type and a sorting result of the extracted OAM information blocks, and extracting content of the OAM information blocks after synchronization so as to monitor the service quality of a carrying pipeline.

The present invention relates to a construction method of a mode-division multiplexing fiber-optic communication system, which includes following contents: converting multiple-input optical signals into optical propagation modes supported by a graded-index ring-core optical fiber at a transmitting end, after being multiplexed by a mode multiplexer, injecting the optical signals into the graded-index ring-core optical fiber for transmission; using a mode de-multiplexer to separate optical signals of different mode groups at a receiving end firstly; and for the separation of internal modes of the same mode group, adopting a multi-channel reception and a digital signal processing method based on a multiple-input multiple-output equalization for processing: for the separation of modes in a base mode group and a high-order mode group, using a digital signal processing algorithm including a 2?2 multiple-input multiple-output equalization and a digital signal processing algorithm including a 4?4 multiple-input multiple-output equalization for recovery processing, respectively. The method according to the present invention only needs to add an optical receiver and a digital signal processing module based on the 4?4 multiple-input multiple-output equalization repeatedly while adding the mode group to expand communication capacity. Compared with the prior art, the present invention has the characteristics of low complexity, high scalability and easy upgrading.

A system for enabling signal penetration into a building includes first circuitry, located on an outside of the building, for receiving signals at a first frequency that experiences losses when penetrating into an interior of the building and converting the received signals at the first frequency into a first format that overcome the losses caused by penetrating into the interior of the building over a wireless communications link. The first circuitry further includes a first transceiver, implementing a first transmission chipset for RF transmissions in the first format that counteracts losses occurring when penetrating into the interior of the building, for receiving the signals at the first frequency and converting the received signals at the first frequency into the first format that overcomes the losses caused by penetrating into the interior of the building. Second circuitry, located on the interior of the building is communicatively linked with the first circuitry for receiving and transmitting the converted received signals in the first format. The second circuitry further includes a second transceiver, implementing the first transmission chipset, for receiving and transmitting the converted signals in the first format from/to the first transceiver on the exterior of the building.

A system for enabling signal penetration into a building includes a first transceiver, located on an outside of the building, for transmitting and receiving signals at a first frequency outside of the building, wherein the signals at the first frequency do not easily penetrate into an interior of the building. A first up/down converter converts between a first version of the signals at the first frequency and a second version of the signals at a second frequency. The first frequency is higher than the second frequency and the signals at the second frequency better penetrate to the interior of the building and overcome losses caused by penetrating into an interior of the building. A second up/down converter converts between the second version of the signals at the second frequency that overcomes the losses caused by penetrating into the interior of the building and a third version of the signals after transmission from the building exterior to the building interior. A router transmits and receives the third version of the signals within the interior of the building.

A system for focusing an orbital angular momentum (OAM) multiplexed beam comprising OAM signal processing circuitry for generating an OAM multiplexed signal. The OAM multiplexed signal includes a plurality of data streams each having a unique orbital angular momentum applied thereto and multiplexed together within the OAM multiplexed signal. Each unique orbital angular momentum has a beam helicity value greater than l=2. An antenna array control circuit controls transmission of the multiplexed OAM signal from each of a plurality of antennas in an antenna array toward a focus point located below the ground as a transmission beam to cause the transmitted OAM multiplexed signals to converge at the focus point below the ground at substantially a same time to overcome a divergence of the transmitted plurality of OAM multiplexed signals caused by the beam helicity value of greater than l=2 for each of the unique orbital angular momentum.

A data storage system is disclosed that includes a recirculating loop storing data in motion. The data may be carried by a signal via the loop including one or more satellites or other vessels that return, for example by reflection or regeneration, the signals through the loop. The loop may also include a waveguide, for example an optical fiber, or an optical cavity. Signal multiplexing may be used to increase the contained data. The signal may be amplified at each roundtrip and sometimes a portion of the signal may be regenerated.

A system for enabling signal penetration into a building includes a transceiver located on an exterior of the building for receiving signals at a first frequency transmitted from a source outside of the building. An optical bridge receives the signals at the first frequency that experiences losses when penetrating an exterior surface of the building, converts the received signals at the first frequency into a first format that overcome losses caused by penetrating an exterior surface of the building and transmits the signals through the exterior surface of the building. A WiFi transceiver located on the interior of the building and connected to the optical bridge converts between the signals in the first format and WiFi signals and for transmitting the WiFi signals to the interior of the building and receiving the WiFi signals from the interior of the building.

Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques for techniques for signaling control information in wireless communication systems based on orbital angular momentum (OAM) modes. One aspect provides a method for wireless communication by a transmitter. The method generally includes transmitting to a receiver, with a first orbital angular momentum (OAM) mode, a first control channel on a first time-frequency resource and transmitting to the receiver, with a second OAM mode, at least one of a data channel or a second control channel on a second time-frequency resource that at least partially overlap with the first time-frequency resource in at least one of time or frequency.