Abstract: The present invention provides a method for converting the topological charge of an orbital angular momentum mode of light to an opposite topological charge by applying the light to a spool of optical fiber having a bend radius R and length L. The length of the fiber used to form the spool is defined by ½ the bend-induced 2? walk-off length Ll,mb(2?). The length of the fiber L and the bend radius R of the spool may be adjusted to account for an ellipticity-induced 2? walk-off length Ll,m3(2?). Using the proportionality rules, Ll,mb(2?)?R2l and Ll,m3(2?)???l adjustments to account for ellipticity induced 2? walk-off length Ll,me(2?), or to account for a change in the bend radius ?R of the spool can be easily determined.

Abstract: The optical fibers disclosed have single mode and few mode optical transmission for VCSEL-based optical fiber transmission systems. The optical fibers have a cable cutoff wavelength ?C of equal to or below 1260 nm thereby defining single mode operation at wavelengths greater than 1260 nm and few-mode operation at wavelengths in a wavelength range from 800 nm and 1100 nm. The mode-field diameter is in the range from 8.0 microns to 10.1 microns at 1310 nm. The optical fibers have an overfilled bandwidth OFL BW of at least 1 GHz·km at at least one wavelength in the wavelength range. The optical fibers have a single-step or two-step core and can have a trench refractive index profile. VCSEL based optical transmission systems and methods are disclosed that utilize both single core and multicore versions of the optical fiber.

Abstract: A system and method for extending the path length of an electromagnetic wave signal traveling between apertures is disclosed.

Abstract: Aspects of the present disclosure describe physical layer security in optical telecommunications networks wherein a filtering-based physical security is provided by a wavelength tunable distributed fiber optical sensing (DFOS) system operating simultaneously on the telecommunications network.

Abstract: Vehicles are equipped with Free-Space-Optics (FSO) transceivers for establishing one or more inter-vehicle communication link. A vehicle, mounted with one or one or more FSO transceiver unit, may enable individual driver to initiate and engage automated communication, exchanging vehicle, road, or driving environment conditions, with another vehicle, forming a vehicle communication network. A group of vehicles may spontaneously, opportunistically, or automatically communicate with each other, forming a vehicle communication network. The FSO transceiver unit enables the determine independently or communicate concomitantly one or more inter-vehicle distance, range, location, speed, velocity, acceleration, using a position locating and range measurement system. Each vehicle can perform unicast, multicast, or broadcast communication using an On-Board Unit containing hardware and software to enable access to the in-vehicle bus systems to collect vehicle information for dissemination in real-time.

Abstract: An example system includes a first network device having first circuitry. The first network device is configured to perform operations including receiving data to be transmitted to a second network device over an optical communications network, and transmitting first information and second information to the second device. The first information is indicative of the data, and is transmitted using a first communications link of the optical communications network and using a first subset of optical subcarriers. The second information is indicative of the data, and is transmitted using a second communications link of the optical communications network and using a second subset of optical subcarriers. The first subset of optical subcarriers is different from the second subset of optical subcarriers.

Abstract: This application provides an optical link fault identification method, and relate to the field of communications technologies. The method includes: obtaining performance data of a network device, extracting a feature parameter of the performance data, and identifying a fault mode on an optical link based on the feature parameter. The method resolves problems of a difficulty in fault identification and slow troubleshooting that are caused by a large quantity of devices, many line faults, and a difficulty in obtaining manual troubleshooting cases. In addition, a fault can be quickly identified when the fault occurs, improving troubleshooting efficiency. When an optical link risk does not cause a fault, deterioration of the performance data can be found in advance based on a feature, to perform identification and warning.

Abstract: An optical repeater in a mode-division-multiplexing (MDM) optical transmission system prevents a signal-to-noise ratio (SNR) from deteriorating due to a loss of a mode demultiplexer. The optical repeater in the MDM optical transmission system is configured to include at least one multimode optical amplifier, a mode demultiplexer, a mode multiplexer, and variable optical attenuators. One of the multimode optical amplifiers is disposed on the input side of the mode demultiplexer.

Abstract: Disclosed is a frequency swept source apparatus including a mode locking laser that outputs an input optical signal having first to n-th frequency components, a transmission delay controller that generates first to m-th sub-optical signals, each of which includes at least one component of the first to n-th frequency components, and outputs a delay optical signal obtained by sequentially delaying the first to m-th sub-optical signals. The transmission delay controller includes a demultiplexer that outputs the first to m-th sub-optical signals to first to m-th channels based on the input optical signal, respectively, a path delay unit that adjusts lengths of optical paths of the first to m-th channels so as to be different from one another, a refractive index controller that adjusts a refractive index of each of the first to m-th channels, and a multiplexer that combines the first to m-th sub-optical signals.

Abstract: A hyperspectral radiometer may comprise one or more antennas, a electro-optical modulator modulating the received RF signal onto an optical carrier to generate a modulated signal having at least one sideband; a filter filtering the modulated signal to pass the sideband to a photodetector; and a photodetector producing an electrical signal from which information of the RF signal can be extracted. In some examples, the optical sideband may be spatially dispersed to provide a plurality of spatially separate optical components to the photodetector, where the spatially separate optical components having different frequencies and correspond to different frequencies of the received RF signal. In some examples, the passed sideband may be mixed with an optical beam having a frequency offset from the optical carrier to form a combined beam having at least one optical signal component having a beat frequency from which information of the RF signal can be extracted.

Abstract: Systems and methods for optical data communication in high temperatures and harsh environments are provided herein. The embodiments utilize a combination of a short wavelength light source combined with a wide bandgap detector in order to transmit optical signals. An optical data communication system may include a light source connected to a light detector via an optical fiber. The light source and the light detector may also be physically adjacent to any dielectric gap that can be spanned without having an optical fiber intermediary.

Abstract: An optical power supply system includes a power sourcing equipment, a powered device, an information obtaining part and a power supply controller. The power sourcing equipment outputs feed light. The powered device converts the feed light into electric power. The electric power is supplied to a communicator. The information obtaining part obtains communication operation information on an operation status of communication that is performed by the communicator. Based on the obtained communication operation information, the power supply controller controls output of the feed light. The communicator is a wireless communicator that performs wireless communication.

Abstract: Disclosed is an optical transmitter module including a directly modulated laser transmitter based on a directly modulated laser (DML) and an arrayed waveguide grating (AWG) chip that is vertically polished. The directly modulated laser transmitter includes a directly modulated laser chip array including one or more directly modulated laser chips, an impedance matching circuit that allows each of the one or more directly modulated laser chips to operate at a critical speed of 100 Gbps per channel or higher, and a radio frequency-flexible printed circuit board (RF-FPCB) that transmits a radio frequency (RF) modulating signal to the directly modulated laser chip array. The arrayed waveguide grating chip includes an optical waveguides that transfer multi-channel optical signals and a wavelength multiplexer that multiplexes the multi-channel optical signals. The directly modulated laser transmitter and the arrayed waveguide grating chip are spaced apart from each other and are optically coupled in chip-to-chip.

Abstract: An integrated communication and ranging system for use on a spacecraft includes: a laser module configured to emit at least one beam, a pointing module configured to direct the at least one beam toward a ground station and toward an object in space, and a detector module configured to detect a scattered portion of the at least one beam. The system further includes a control module configured to operate the pointing module to (i) transmit data to the ground station using the at least one beam and (ii) determine, using the detector module, a distance between the spacecraft and the object using the at least one beam.

Abstract: To n antenna elements of the base station, n wavelengths set at predetermined intervals in a range in which chromatic dispersion in an optical fiber between accommodation and base stations can be regarded as constant are assigned. The accommodation station adjusts the phases of optical signals of the wavelengths or modulated signals that modulate the optical signals such that the amounts of phase shift of their RF signals are at predetermined intervals. The accommodation station transmits beacon signals multiple times while varying a transmission phase shift interval ?1 and the terminal transmits beacon number information of a beacon signal selected based on received power multiple times. The accommodation station varies a reception phase shift interval ?2 for each piece of beacon number information to determine a reception phase shift interval ?2 which maximizes the received power and determines the transmission phase shift interval ?1 based on the beacon number information received from the terminal.

Abstract: Methods and systems relating to administration of access credentials for electronic access control are disclosed. Web resources are provided for rendering a webpage including an access credential. A server device receives an access instruction authorizing a user to access an electronic lock associated with the access credential. A client device of the user transmits a first request for the access credential. The first request may be generated by a browser application of the client device. The server device provides the web resources and a browser cookie to the client device. Responsive to subsequent requests for the access credential, the server device determines whether the client device is authorized to receive the access credential based on the client device providing the browser cookie. When the server device determines that a subsequent request authorizes the client device to receive the access credential, the web resources are provided to the browser application.

Abstract: An optical link for a communication network, the optical link having an optical fibre link, a downstream transmitter, a downstream receiver, an upstream transmitter and an upstream receiver. The upstream and downstream transmitters are configured to transmit a respective pilot tone on a respective optical carrier and are configured to tune a frequency of the pilot tone within a preselected frequency range. The upstream and downstream receivers are configured respectively to determine an upstream notch frequency, fnotch-US, and a downstream notch frequency, fnotch-DS, of respective detected photocurrents from at least one respective pilot tone frequency at which the respective detected photocurrent is equal to or lower than a photocurrent threshold. The optical link also includes processing circuitry configured to receive the upstream and downstream notch frequencies and configured to estimate a propagation delay difference of the optical link depending on the upstream and downstream notch frequencies.

Abstract: Disclosed are optical communications systems and optical receivers including one or more optical cavity resonators. In particular, disclosed are methods and apparatus that allow for beam pointing to be maintained while permitting the receiver to tune the optical resonator to suit the wavelength, data rate and modulation format of the incoming optical signal, without requiring a coherent receiver or adaptive optics in addition to optical resonators.

Abstract: Various example embodiments of the present disclosure relates to a physical layer, PHY, circuitry for an optical line terminal, OLT, the PHY circuitry being configured to receive a control signal including an identification of a transmitting ONT for pre-loading an equalization configuration associated with the identification of the transmitting ONT. Other example embodiments relate to a medium access control, MAC, circuitry for OLT, the MAC circuitry being configured to determine an upstream allocation map for optical network terminals, ONTs, and to generate a control signal for a PHY circuitry including synchronization information for receiving upstream optical signal bursts from a transmitting ONT and an identification of the transmitting ONT based on the upstream allocation map. Further example embodiments related to an optical line terminal, OLT, and a method therefor.

Abstract: A construction and configuration for the receiving function of a high speed optical communication system with reduced manufacturing cost and improved performance. In an aspect, mounting the cover and lens provides a self-alignment behaviour that advantageously positions the cover and the lens to be in the optimum position for the photodiode. An assembly of electronic components receives data using an optical fibre. In one aspect, the assembly includes a photodiode, an amplifier coupled to the photodiode, and a printed circuit board on which the photodiode and amplifier are physically mounted, The printed circuit board has areas of a first material to which components may be attached using a fixing agent, and areas of a second material to which components will not attach using the fixing agent. Conductive bond wires are configured to directly couple the amplifier and the photodiode to conductive traces on an opposite side of the printed circuit board.