Abstract: A procedure for transferring wavelengths, and a system that operates in accordance with the procedure. The system comprises at least one network terminal, each including a switch and a controller. A plurality of wavelength sets are applied to the switch. The controller is arranged to operate the switch such that the switch (a) selects at least one wavelength from at least one of the plurality of wavelength sets, based on electrical monitoring at a port module external to the network terminal, and (b) outputs the at least one wavelength to an output of the at least one network terminal.

Abstract: Exemplary embodiments described herein include a bi-directional Free Space Optical (FSO) communication unit that may be used in a multi-node FSO communication system. The bi-directional FSO unit may include a co-boresighted optical unit such that received and transmitted beams are coincident through a common aperture. Embodiments described herein may be used to correct or accommodate the alignment errors of the received and transmitted beams.

Abstract: An interconnection system, an apparatus, and a data transmission method. In the interconnection system, to-be-transmitted data is converted into a data packet in an optical signal form for transmission, and a control packet corresponding to the data packet is transmitted in an electrical signal form and includes routing information of the data packet. When the control packet passes through a switching node, the switching node directly determines, according to the routing information in the control packet, a neighboring node that serves as a next hop, and opens, in the switching node, an optical path used to transmit the data packet. Because no optical-to-electrical or electrical-to-optical conversion needs to be performed on the control packet and the data packet during an entire transmission procedure, problems of an extra delay and power consumption caused by electrical-optical-electrical conversion can be reduced, thereby improving data transmission efficiency.

Abstract: A method and apparatus for approaches for troubleshooting optical networks, particularly ROADM-based networks is described. The method includes designating a first port, of an optical communication node of a transport network, as an ingress for a loop-back optical signal to troubleshoot the transport network, designating a second port, of the optical communication node, as an egress for the loop-back optical signal, and establishing a loop-back connection between the first port and the second port to transport the loop-back optical signal.

Abstract: An apparatus of a passive optical network (PON) comprising an optical line terminal (OLT) component configured to couple to an optical network unit (ONU) and send downstream wavelength identification to the ONU to indicate a wavelength that corresponds to the ONU, wherein the downstream wavelength identification is transmitted using a Media Access Control (MAC) layer frame for an embedded channel, a control message channel, or a data channel. Also included is an apparatus of a PON comprising an ONU component configured to couple to an OLT and send upstream wavelength feedback to the OLT to indicate a wavelength that corresponds to the ONU, wherein the upstream wavelength feedback is transmitted using a MAC layer frame for an embedded channel, a control message channel, or a data channel.

Abstract: Techniques are presented herein to enable identification of light fixtures. A light fixture modulates light emitted by the light fixture with an identifier associated with the light fixture. The identifier may be encoded or encrypted before it is modulated. In one example, the identifier is a Universally Unique Identifier (UUID). A user device is positioned to detect light emitted by the light fixture. The user device demodulates the light to obtain the identifier. The identifier, time and location associated with detection of the identifier are sent to a management entity for use in provisioning the light fixture on a network.

Abstract: A method of automated testing and evaluation of a node of a communications network, the method comprising: a management computer interacting with the node to discover fiber trails within the node that can be safely tested; and the management computer interacting with the node to test at least continuity of each identified fiber trail that can be safely tested.

Abstract: A communications controller, and corresponding method therein, for wavelength control of a first and second channel. The first and second channels are bidirectional and adjacent to one another in a single fiber in a Dense Wavelength Division Multiplexing (DWDM) based system.

Abstract: A method, apparatus, and system for network monitoring, and more specifically for correlating downstream devices in an optical network with downstream ports of an optical splitter through which they are communicating with a central office. The downstream devices operational on the network are indentified and listed in a correlation table. Selected subsets of these devices are then monitored, preferably by an ISM under the direction of a management node, in a series of monitoring cycles until a satisfactory correlation may be achieved. The correlation cycle may be performed at startup, as needed, or on a periodic basis.

Abstract: System and method embodiments are provided for improving reception of direct detection optical signals. In an embodiment, a method for optical transmission includes bit loading and power loading, with a digital signal processor (DSP), transmission bits of an orthogonal frequency-division multiplexing (OFDM) signal; calculating, with the DSP, a signal-signal beat interference (SSBI) component of the bit and power loaded OFDM signal by modulating each subcarrier with a symbol; and subtracting, with the DSP, the calculated SSBI component from the bit and power loaded OFDM signal.

Abstract: Embodiments of the present disclosure are directed toward techniques and configurations for an optical apparatus to control optical power of the light source. In one embodiment, the apparatus may include a transmitter and receiver to transmit and receive optical signals over an optical communication channel, and a controller to cause the transmitter to transmit pulse signals at a first power level and detect a change in optical power in the channel, indicating a presence of a signal from another optical apparatus. The controller may confirm that the detected apparatus is capable of communications at a second power level (greater than the first level) and initiate data transmission at the second level. Upon detection of a failure in the channel, the controller may cause the transmitter to halt the data transmission and restart the pulse signals at the first power level. Other embodiments may be described and/or claimed.

Abstract: Systems and methods for using a dispersion compensation circuit to directly modulate a laser. Techniques include calibrating a varactor bias point in a dispersion compensation circuit during manufacturing, but positioning the dispersion compensation circuit between a first attenuator and a second attenuator. Each attenuator, capable of reducing power of an input signal, may be adjustable so that the attenuation provided by each attenuator may be adjusted. The ratio of attenuation between attenuators may be adjusted based on either chirp of a laser or fiber length, and a varactor bias point may be adjusted by the other one of the chirp of the laser or fiber length. Thus, both chirp and fiber length may serve as a basis for adjusting attenuation between attenuators having a dispersion compensation circuit positioned between them.

Abstract: Transmission apparatus for beam expansion are disclosed. A transmission apparatus includes a light source configured to emit an optical signal, a first feature comprising a diffractive element and a reflective element, and a second feature that is substantially aligned with the first feature. The diffractive element is substantially aligned with the light source to receive the optical signal. The second feature includes an inner surface that is partially reflective and partially transmissive. The first feature is located between the light source and the second feature. The diffractive element is configured to diffract the optical signal, the second feature is configured to: (a) reflect a first portion of the diffracted optical signal and (b) transmit a second portion of the diffracted optical signal to a destination balloon; and the second feature is further configured to transmit at least part of the first portion of the diffracted optical signal to the destination balloon.

Abstract: A method and apparatus for performing path protection for rate-adaptive optics is provided. As part of the method, an aggregate input bit stream is received. The aggregate input bit stream is then transmitted using a rate-adaptive optical transceiver when transmitting on a first optical path. When the first optical path has a fault, the aggregate input bit stream is then transmitted on a second optical path using the rate-adaptive optical transceiver and a fixed-rate optical transceiver.

Abstract: An apparatus is described which uses directly modulated InGaN Light-Emitting Diodes (LEDs) or InGaN lasers as the transmitters for an underwater data-communication device. The receiver uses automatic gain control to facilitate performance of the apparatus over a wide-range of distances and water turbidities.

Abstract: Embodiments of the disclosure are directed to optimizing routing and wavelength assignment in a network. An embodiment determines a routing assignment for a network, wherein the routing assignment is determined using a decongestion cost-based function; and determines a wavelength assignment for the network based on vector difference. The determination of the wavelength assignment comprises spanning the network for a path; calculating a weighted correlation function for at least one length in the network; storing the weighted correlation; and determining if a next path exists. If a next path is found, spanning for a next path in the network, and if a next path is not found, returning the stored correlation.

Abstract: Systems, devices, and methods for hybrid anti-clipping in optical links in hybrid fiber-coaxial (HFC) networks are disclosed. A hybrid anti-clipping circuit can be included in both the uplink and downlink paths of the HFC network to avoid driving the laser in the optical link above a clipping threshold. The anti-clipping circuit can compare the average, or RMS, input power level and the power envelope of a RF input signal to a clipping threshold associated with the particular laser module being used. If the average power is above the clipping threshold, then the input signal can be attenuated proportionally to avoid clipping. If peaks in the power envelope are above the clipping threshold, then the bias current of the laser module can be adjusted to avoid clipping. Accordingly, the modes of anti-clipping circuit operation include applying attenuation to the input signal and/or adjusting the laser module bias current.

Abstract: An apparatus comprises a passive wavelength division multiplexing (WDM) demultiplexer (DeMUX) or a passive WDM multiplexer (MUX), an active photo diode (PD) array or an active laser diode (LD) array, and a compressing device disposed between the passive WDM DeMUX or the passive WDM MUX and the active PD array or the active LD array. The compressing device changes the optical spot pitch of the passive WDM DeMUX or the passive WDM MUX to match the pitch of the active PD array or the active LD array. The compressing device may be a single optical wedge, a first and a second optical wedges, a plurality of optical wedges, or a grating. A compression ratio can be adjusted by changing the incident angle of the incident beam to the compressing device.

Abstract: There is provided a method for detecting modulated light comprising: receiving a set of images acquired by means of a rolling shutter camera having image acquisition settings comprising a frame rate, fframe, and a line rate, fline; identifying in consecutive frames of said images—a pattern governed by the ratio between a modulation frequency, fc, of a modulated light source and the line rate, fline, and—between consecutive frames a spatial shift of said pattern governed by the ratio between said modulation frequency fc, and said frame rate, fframe; and providing based on said pattern and spatial shift thereof, an estimate of the modulated light amplitude from said light source.

Abstract: The present invention relates to a device and a method for conversion from optical double-sideband modulation signals to optical single-sideband modulation signals. Period-one nonlinear dynamics of semiconductor lasers is utilized to achieve such optical signal conversion. Only a typical semiconductor laser is required as the key conversion unit. The microwave and data quality are maintained or even improved after conversion, increasing detection sensitivity, transmission distance, and link gain of the communication networks. The device is relatively less sensitive to ambient variations, can be self-adapted to changes in operating conditions, and can be applied for a broad range of operating microwave frequency up to at least 80 GHz and a high data rate up to at least 2.5 Gbits/s. The device can therefore be dynamically reconfigured for different communication networks adopting different operating microwave frequencies and different data rates.