Abstract: The disclosed systems and methods for characterizing an optical fiber in a dense wavelength division multiplexing (DWDM) optical link. The characterizing comprising: i) applying a power dither to data bearing optical signals propagating in the optical fiber, the power dither having a high-power level and a low-power level; ii) computing optical time-domain reflectometer (OTDR) traces corresponding to the high-power level and the low-power level of the power dither; iii) averaging the OTDR traces corresponding to the high-power level and the OTDR traces corresponding to the low-power level into average OTDR traces; computing a differential Stimulated Raman Scattering (SRS) gain from the OTDR traces; and iv) adjusting the average OTDR traces based on the differential SRS gain.

Abstract: Aspects of the present disclosure describe distributed fiber optic sensing (DFOS) systems, methods, and structures that advantageously overcome problems encountered when operating DFOS systems over operational telecommunications facilities namely, cross-phase modulation, and uneven amplitude profiles through the use of a novel constant amplitude coded DFOS employing suppressed out-of-band signaling.

Abstract: A transmission device includes: a memory; and a processor coupled to the memory and configured to: transmit or receive an optical signal; filter an electrical electric field signal that indicates electric field information of the optical signal; calculate a transmission characteristic of filtering of the electric field signal and set the transmission characteristic in the filter on a basis of a narrowing amount of a wavelength band of the optical signal transmitted through a transmission line and a narrowing amount of the wavelength band when a state of the transmission line is changed on a basis of transmission line information regarding the transmission line of the optical signal; and set a transmission parameter of the optical signal according to quality of the electric field signal filtered by the filter.

Abstract: A receiving device includes a light source outputting local oscillation light, a detector detecting intermittent input of a burst light signal by using the local oscillation light, a first converter converting the detected burst optical signal into an electrical analog signal, an amplifier amplifying the analog signal according to a gain, a second converter converting the amplified analog signal into a digital signal, and a setting processor setting the gain of the amplifier and a wavelength of the local oscillation light instructed by a control device when setting a communication line with one of transmitting devices transmitting the burst optical signal, wherein, before setting the communication line, the setting processor switches the wavelength of the local oscillation light according to the burst optical signal transmitted from each of the transmitting devices, adjusts the gain of the amplifier and notifies the control device of the adjusted gain.

Abstract: Coherent optical communications technology for recovery of 1D and 2D formatted optical signals. For example, 1D or 2D formatted signals that travel through fiber optic media may be recovered by separating the light into X- and Y-polarization components, rotating one polarization component (e.g., Y-component) into the polarization space of the other component (e.g., Y-component into the X-polarization space), delaying the rotated component enough to avoid destructive interference and combining the delayed component with the undelayed component to form a folded optical signal, which may then be processed as a X-polarized signal.

Abstract: A node (10) includes multiplexing unit (11) that multiplexes a plurality of subcarrier signals for performing optical wavelength multiplexing communication into a wavelength group signal; output unit (12) that outputs the multiplexed wavelength group signal to an optical transmission line; pre-multiplexing level correction unit (13) that corrects a level deviation between the subcarrier signals before the multiplexing based on an optical level of the wavelength group signal in the output unit (12); and post-multiplexing level correction unit (14) that corrects a level deviation of the wavelength group signal after the multiplexing including the corrected subcarrier signals based on the optical level of the wavelength group signal in the output unit (12).

Abstract: An apparatus for mitigating polarization dependent loss (PDL) in an optical signal-to-noise ratio (OSNR) of a modulated optical signal is disclosed. The apparatus may comprise a spectrum analyzer to measure an optical power spectrum of a modulated optical signal. The apparatus may also comprise a measuring unit to select a first portion of the modulated optical signal and a second portion of the modulated optical signal, where each of the first and second portions of the modulated optical signals may include an independent noise distribution indicative of PDL, and measure a time-varying parameter of the first and second portions. The apparatus may also include a signal processor to PDL in an OSNR by transforming any elliptical polarization associated with the independent noise distribution into a ball polarization, determining a correlation between time-varying parameters of the first and second portions, and calculating a PDL mitigated OSNR.

Abstract: The disclosed systems and methods for processing a subcarrier-multiplexed signal comprising: i) mixing the subcarrier-multiplexed signal with a local oscillator (LO) signal; ii) extracting a respective subcarrier signal from the subcarrier-multiplexed signal; iii) sampling the respective subcarrier signal; iv) extracting timing recovery information from the respective subcarrier signal; and v) processing the respective sampled subcarrier signal to extract data from the respective sampled subcarrier signal.

Abstract: An optical communications network comprises optical data links interconnected by add-drop nodes, the optical data links comprising data channels. The data channels are allocated into equal-sized bins. In response to a first data channel request between a given source-destination pair, one of the equal-sized bins is assigned to the data channel request. In response to requests for additional bandwidth for the same source-destination data channel request, unused channels within the assigned equal-sized bin are allocated to the data channel request. In response to subsequent data channel requests between different source-destination pairs, additional unallocated equal-sized bins are assigned to the subsequent data channel requests. In response to subsequent data channel requests when resource sharing for one equal-sized bin, data channels in the last equal-sized bin are assigned using the reverse channel assignment process. Reverse channel assignment can also be used for other bins as an option.

Abstract: An optical communications system includes a modulator/demodulator (modem) to transmit outgoing communications data and to receive incoming communications data in a transceiver. A main detector is coupled to the modem to convert an optical signal representing the incoming communications data to an electrical signal for the modem. An adaptive data rate processor monitors the electrical signal from the main detector to determine a current power level for the optical signal. The adaptive data rate processor dynamically adjusts a data rate of the modem based on the determined current power level of the optical signal.

Abstract: A pointing unit 102 is for use with a free space optical communications terminal 100 including an optical source 104. The pointing unit 102 includes a first portion 106 having a mirrored surface 108, the first portion 106 being orientatable relative to an optical beam 110 produced by the optical source 104 and incident on the mirrored surface 108 in use to direct a reflection 112 of the optical beam 110 from the mirrored surface 108 towards a target 107. The first portion 106 further includes a directional radio frequency antenna 114.

Abstract: The invention relates to a power-over-fiber (PoF) system, comprising: an optical source configured to generate an optical signal, wherein the optical signal comprises an intensity modulation; an optical fiber configured to receive the optical signal from the optical source and to guide the optical signal; an optical sink, which is configured to receive the optical signal from the optical fiber and to convert the optical signal into an electrical signal; a detection unit, which is configured to detect at least one characteristic of the electrical signal, wherein the characteristic is at least partially caused by the intensity modulation of the optical signal; and a control unit, which is configured to control the optical source based on the detected characteristic.

Abstract: Provided is a coherent detection implementing apparatus, system and method. The apparatus includes: a first transceiver unit, configured to send an optical signal in a first direction to a second device, wherein the optical signal in the first direction includes a direct current optical signal with a first wavelength and a modulated optical signal with a second wavelength; and configured to receive an optical signal in a second direction from the second device; and a first coherent receiver, connected with the first transceiver unit, and configured to take a part of the direct current optical signal with the first wavelength in the optical signal in the first direction as a Local Oscillator (LO) light for coherent reception, perform coherent frequency mixing between the LO light and the optical signal in the second direction, and demodulate the optical signal in the second direction.

Abstract: Premises apparatus and methods for providing aggregated high-bandwidth, low-latency data service over a content delivery network including existing wireline infrastructure. In one embodiment, a network architecture having service delivery over at least portions of extant hybrid fiber coax (HFC) infrastructure is disclosed, which includes standards-compliant ultra-low latency and high data rate services (e.g., 3GPP and IEEE Std. 802.11 services) via a common service provider. In one variant, an expanded frequency band (e.g., 1.6 GHz in total bandwidth) is used over the coaxial portions of the HFC infrastructure, which is allocated to two or more sub-bands. Premises apparatus are used to support multi-service integration (e.g., aggregation of mobile wireless, premises, and other services), as well as incipient IoT applications and technologies.

Abstract: An optical network communication system utilizes a passive optical network (PON) and includes an optical line terminal (OLT) having a downstream transmitter and an upstream receiver, and an optical network unit (ONU) having a downstream receiver and an upstream transmitter. The downstream transmitter is configured to provide a coherent downlink transmission, and the downstream receiver is configured to obtain one or more downstream parameters from the coherent downlink transmission. The system further includes a long fiber configured to carry the coherent downlink transmission between the OLT and the ONU. The ONU is configured to communicate to the OLT a first upstream ranging request message, the OLT is configured to communicate to the ONU a first downstream acknowledgement in response to the upstream first ranging request message, and the ONU is configured to communicate to the OLT a second upstream ranging request message based on the first downstream acknowledgement.

Abstract: A signal processing device included in an optical reception device configured to receive a burst optical signal transmitted by one of a plurality of optical transmission devices, includes a symbol timing detecting unit configured to detect a symbol timing based on sample signals obtained by oversampling the burst optical signal converted into an electric signal with a sampling rate higher than a symbol rate, an adaptive equalization filter unit configured to perform an equalization process on the sample signals, and a timing matching unit configured to match timing such that, when the adaptive equalization filter unit takes in the sample signals, one of the taken-in sample signals corresponding to the symbol timing is given to a tap of which a tap coefficient has a maximum value among taps included in the adaptive equalization filter unit.

Abstract: A method is provided for calibrating a terminal device connected to a transmission line containing an impairment. The method includes steps of obtaining a sequence of frequency domain samples for a digital signal transmitted to the terminal device, determining a reflection coefficient from the obtained frequency domain sequence and a reflection signal arising from the impairment, converting the sequence of frequency domain samples and the frequency domain reflection signal into the time domain to generate a complex time domain sample sequence having a real I time component and an imaginary Q time component, correcting the time domain sample sequence into a corrected time sequence having a phase value of the Q component corresponding to a phase value of the I component, calculating a correcting spin coefficient from the corrected time sequence, and calibrating the terminal device with the correcting spin coefficient to mitigate a rotation of the reflection coefficient.

Abstract: In a general aspect, a communication system comprises a first station and a second station. The first station includes a photonic crystal maser, a laser subsystem, and a tracking subsystem. A photonic crystal structure of the photonic crystal maser is formed of dielectric material and has an array of cavities and an elongated slot. The elongated slot is disposed in a defect region of the array of cavities. The photonic crystal maser also includes a vapor disposed in the elongated slot and operable to emit a target RF electromagnetic radiation in response to receiving an optical signal. The array of cavities and the elongated slot define a waveguide configured to form the target RF electromagnetic radiation, when emitted, into a beam. The second station includes a receiver configured to couple to the beam of target RF electromagnetic radiation.

Abstract: A transmission method includes: in a first period, causing a light source to emit light having a first luminance; and in a second period, causing the light source to transmit an optical signal by causing the light source to alternately emit light having a second luminance and light having a third luminance lower than the second luminance.

Abstract: A method includes determining a first power level by performing a first series of measurements based on a first series of burst transmissions from an optical transmitter of an optical network unit (ONU) in an optical network. Bursts in the first series of burst transmissions include a first modified preamble. A second power level is determined by performing a second series of measurements based on a second series of optical burst transmissions. Bursts in the second series of burst transmissions include a second modified preamble. A first power level (P0) and a second power level (P1) are determined based on the first power level and the second power level and one or more additional parameters associated with transmissions from the optical transmitter are determined based on P0 and P1. Based on the additional parameters, it is determined whether the optical transmitter complies with specifications of the optical network.