Abstract: A common method of down converting a received RF signal mixes the received RF signal with a LO signal to create a beat signal. Exemplary embodiments can address multiple simultaneously received RF signals which beat within receiver electronics at frequencies similar to that of the down converted signals. An RF mixer is disclosed using a photonic circuit arranged to impose the RF signal and the LO signal onto separate optical beams. An arrangement provides a beam carrying the RF signal to a first optical input of a balanced photodiode receiver and another beam carrying the RF and LO signals to a second optical input of the balanced photodiode receiver. Any beat products formed between different RF signals will be cancelled out at the electrical output of the balanced photodiode receiver.

Abstract: A package includes a light emitting portion configured to emit light, a lens including a first lens surface and a second lens surface, a protective layer between the light emitting portion and the first lens surface and that shields the first lens surface from a surrounding environment, and an optical component that redirects light output from the second lens surface. The first lens surface is configured to receive the emitted light from the light emitting portion, the second lens surface is configured output light that has passed through the first lens surface, and the protective layer has a refractive index greater than 1.5.

Abstract: A downhole optical communications system provided at a downhole location in use, the downhole communications system being for communicating between the downhole location and an uphole location, such as a surface location. The downhole optical communications system comprises a downhole optical transmitter configured to emit an optical signal for transmission over an optical transmission channel between the uphole location and the downhole optical transmitter; wherein the downhole optical transmitter is configured so as to produce a response to an optical signal received from the optical transmission channel and the downhole optical communications system is configured to determine data represented by the received optical signal from the response produced by the downhole optical transmitter.

Abstract: A modulating circuit adapted to modulate between an energy harvesting mode and a wireless transmitter mode is disclosed which includes a solar cell, an energy-harvesting circuit, a first switch coupling the solar cell to the energy harvesting circuit and controlled by a first control line, a second switch coupling the solar cell to a programmable current source and controlled by a second control line, a transmitter/energy harvesting mode circuit adapted to select between a transmitter mode and an energy harvesting mode, and a symbol-to-current mapping circuit adapted to encode data to be communicated by the solar cell, the symbol-to-current mapping circuit adapted to adjust the programmable current source to thereby provide a metered current to the solar cell.

Abstract: A method for implementing an out-of-band communication channel in a coherent optical access network includes steps (a)-(e). Step (a) includes separating a MAC-layer signal received from a media access control (MAC) layer into an initial communication-channel signal and an initial data-channel signal. Step (b) includes encoding, using a first signal-coding scheme within a transceiver of a coherent passive optical network (PON), the initial communication-channel signal into a communication-channel signal occupying a first frequency band. Step (c) includes encoding, using a second signal-coding scheme within the transceiver, the initial data-channel signal into a data-channel signal occupying a second frequency band not overlapping the first frequency band. Step (d) includes combining the communication-channel signal and the data-channel signal to yield an analog signal.

Abstract: Automatic optical link calibration systems and methods include an optical node with an Optical Add-Drop Multiplexer (OADM) multiplexer including a channel holder source; an optical amplifier connected to the OADM multiplexer and to a fiber span; an Optical Channel Monitor (OCM) configured to monitor optical spectrum before and after the optical amplifier; and a controller configured to obtain data associated with the fiber span including measurements from the OCM, determine settings of the channel holder source needed to meet a target launch power profile for the fiber span, and configure the channel holder source based on the determined settings.

Abstract: A passive dual polarization unit and coherent transceiver and/or receiver including one or more passive dual polarization units are provided. An example passive dual polarization unit includes a polarization splitter configured to split an input signal into a TE mode and TM mode signals; TE/TM splitters each designed to split the TE/TM mode signals into first TE/TM signals and second TE/TM signals; a first TE signal polarization rotation component for receiving the first TE signal and providing a third TM signal having the same magnitude and time dependence as the first TE signal; a first TM signal polarization rotation component for receiving the first TM signal and providing a third TE signal having the same magnitude and time dependence as the first TM signal; and TE/TM couplers that couple the second TE/TM signals and the third TE/TM signals to generate output TE/TM signals.

Abstract: An unused path through which actual data is not transmitted in a long-distance redundant network can be appropriately detect, and this function is realized at low cost. A transmission unit 33 of optical transceivers 21a and 21b connected to each other by an optical fiber cable 22 in an optical transmission system 20 includes a laser 37 for emitting a laser beam serving as an optical signal P1 to the optical fiber cable 22, and an optical intensity control unit 35 for performing control to change the optical level of the optical signal of the laser beam.

Abstract: An optical transceiver monitoring system includes an optical transceiver device that includes a non-volatile memory system, and a computing device that includes a computing device port that is coupled to the optical transceiver device. The computing device monitors the computing device port and, in response, detects one or more interactions between the optical transceiver device and the computing device. The computing device determines that the one or more interactions satisfy an event condition, and in response to the one or more interactions satisfying the event condition, provides first event information that corresponds to the one or more interactions to the optical transceiver device for storage in the non-volatile memory system.

Abstract: A communication interface comprising a host with non-linear equalizers configured to perform non-linear equalization. Also part of the interface is a host to optic module channel electrically connecting the host to an optic module and the optic module. The optic module comprises a transmitter and a receiver. The transmitter includes a linear equalizer and an electrical to optical module configured to convert the equalized signal from the driver to an optical signal, and transmit the optical signal over a fiber optic cable, such that the transmitter does not perform non-linear processing. The receiver includes a photodetector, configured to convert the received optic signal to a received electrical signal, and a linear amplifier configured to perform linear amplification on the received electrical signal. A driver sends the amplified received signal over an optic module to host channel, such that the receive does not perform non-linear processing.

Abstract: Disclosed are systems for transmitting and receiving a radio frequency (RF) signal and an optical signal. One system may include a communication terminal comprising a primary concave reflector providing a first focal length to a focal point, and a secondary concave reflector providing a second focal length to the focal point. The communication terminal may further comprise an optical transceiver facing the secondary concave reflector, and one or more RF transceivers facing the primary concave reflector. The optical transceiver may be configured to transmit and receive the optical signal via the primary and secondary concave reflectors through the focal point, and the one or more RF transceivers may be configured to transmit and receive the RF signal via the primary concave reflector. The one or more RF transceivers may be positioned adjacent to the focal point and offset from a path of the optical signal.

Abstract: In some examples, high speed bidirectional OTDR-based testing may include transmitting data from a first end of a device under test (DUT) towards an optical time-domain reflectometer (OTDR) that is operatively connected to a second opposite end of the DUT. Further data that is transmitted by the OTDR may be received from the second opposite end of the DUT towards the first end of the DUT. Based on an amplitude of the further data, a direction of receiving of the further data may be adjusted towards a first receiver or towards a second receiver.

Abstract: An optical detector system provides output to an optical tracking system to facilitate optical communications by tracking a beam of incoming light using a fast-steering mirror (FSM). The optical detector system comprises an array of optical photodetectors, such array comprising one or more quad cells. The incoming light passes through one or more optical elements to generate a specified beam shape, such as a bar or cross, on the array. The resulting output from the array is highly responsive to changes in position of the reshaped beam on the array. As a result, noise equivalent angle (NEA) of the optical detector system representing pointing error is substantially reduced. A reduction in NEA facilitates more precise alignment, allowing incoming light to be aligned to a smaller area. For example, the incoming light may be aligned to a single mode optical fiber connected to a receiver system.

Abstract: Example embodiments disclose a tunable optical pair source (TOPS) configured to generate first and second output optical beams having respective first and second frequencies that are phase locked with each other. The TOPS may include a first laser, such as a tunable laser, configured to generate a first laser beam, a radio frequency (RF) oscillator configured to transmit an RF reference signal, a beam splitter in optical communication with the first laser, and an electro-optic modulator configured to modulate the second split beam with the RF reference signal to form a modulated beam having a first sideband comb comprising a plurality of harmonics. Additionally, the TOPS may include an optical filter configured to receive the modulated beam and output a filtered optical beam, and a second laser configured to generate a second laser beam at the second frequency, the second laser being configured to receive the filtered optical beam as a seed.

Abstract: A line monitoring system may include a laser source to launch a probe signal over a first bandwidth, a polarization maintaining tap to receive and split the probe signal, into a first portion and a second portion, a polarization rotator to receive the first portion and send the first portion to a transmission system, a return tap to receive the second portion and to receive a return signal from the transmission system, wherein the return signal being derived from the first portion, a photodetector coupled to receive an interference signal from the return tap, wherein the interference signal is generated by a mixing the return signal and the second portion, where the photodetector is arranged to output a power signal based upon the interference signal, and a power measurement system to measure the power signal at a given measurement frequency over a second bandwidth, comparable to the first bandwidth.

Abstract: Provided is an optical communication system configured as an optical ring network including: a first optical communication device configured to transmit a first optical signal having a first wavelength in a first direction, and to transmit a second optical signal having a second wavelength in a second direction opposite to the first direction; and a second optical communication device configured to generate a first reflected signal by reflecting the first optical signal when the first optical signal is received, to generate a second reflected signal by reflecting the second optical signal when the second optical signal is received, and to transmit the first and second reflected signals to the first optical communication device, wherein the first optical communication device analyzes a connection state of the second optical communication device based on the first and second reflected signals.

Abstract: Provided is a multi-channel, bi-directional optical communication module.

Abstract: A method comprising: receiving a multiplexed optical signal comprising optical channels for N wavelengths, N being a positive integer greater than or equal to two; and separating the multiplexed optical signal into a first multiplexed light and a second multiplexed light, each of the first multiplexed light and the second multiplexed light having the same polarization, and each of the first multiplexed light and the second multiplexed light having N wavelengths; separating the first multiplexed light into a plurality of first lights, each having a different wavelength; separating the second multiplexed light into a plurality of second lights simultaneous with separating the first multiplexed light into the first lights, each of the second lights having a different wavelength; and generating optical parameters for each optical channel in the N wavelengths using the first light and the second light for each wavelength.

Abstract: An object is to respectively provide excitations light from a plurality of light sources to an odd number of fiber pairs. Optical amplifiers are disposed in three fiber pairs including two optical fibers through which optical signals are transmitted, respectively. The optical multiplexer/demultiplexer has inputs connected to light sources and three outputs. An optical multiplexer/demultiplexer has inputs connected to light sources and three outputs. In optical multiplexers/demultiplexers, one input is alternatively connected to any one of the three outputs of the optical multiplexer/demultiplexer, the other input is alternatively connected to any one of the three outputs of the optical multiplexer/demultiplexer, one output is alternatively connected to one optical fiber of any one of the three pairs, and the other output is alternatively connected to the other optical fiber of any one of the three pairs.

Abstract: This application relates to the field of space communications technologies, and provides an acquisition, pointing, and tracking (APT) subsystem and a spacecraft communications system. The APT subsystem includes a first controller, a first terahertz transceiver, and a terahertz antenna array that are sequentially connected, where the first terahertz transceiver is configured to modulate and demodulate a terahertz wave; the terahertz antenna array is configured to send and receive the terahertz wave; and the first controller is configured to control the first terahertz transceiver to acquire, point, and track another APT subsystem by using the terahertz antenna array.