Abstract: A communication system includes an OFDMA transmitter (Tx) at an optical line terminal (OLT) generating an OFDMA signal by assigning orthogonal subcarriers to different cell sites through digital logic, an electrical multiplexer combining the electrical OFDMA signal with two electrical clock signals, and an optical intensity modulator intensity-modulating the resulting joint electrical OFDMA+clocks signal; an optical multiplexer receiving aggregate OFDMA signals on multiple wavelengths with tight DWDM ?-spacing; a remote node (RN) receiving the OFDMA signals, such that each wavelength is distributed by a de-multiplexer (Demux) to designated general small cell area, to which cell sites are connected by optical splitters; and an optical network unit (ONU) to directly photodetect and digitize received OFDMA signal, wherein downstream (DS) information for each cell is digitally extracted and prepared for wireless radio frequency (RF) transmission over an air interface, and an electrical splitter and bandpass filte

Abstract: RFID (radio frequency identification) systems are provided in which tag and interrogator devices implement a hybrid framework for signaling including an optical transmitter/receiver system and an RF transmitter/receiver system. For instance, an RFID tag device includes: optical receiver circuitry configured to receive an optical signal having an embedded clock signal from an interrogator device, and convert the optical signal into an electrical signal comprising the embedded clock signal; clock extraction circuitry configured to extract the embedded clock signal from the electrical signal, and output the extracted clock signal as a clock signal for controlling clocking functions of the tag device; voltage regulator circuitry configured to generate a regulated supply voltage from the electrical signal, wherein the regulated supply voltage is utilized as a bias voltage for components of the tag device; and data transmitter circuitry configured to wirelessly transmit tag data to the interrogator device.

Abstract: A small form factor pluggable (“SFP”) transceiver for use in a communications network includes a transmitter adapted to be coupled to the network for supplying signals to the network, a receiver adapted to be coupled to the network for receiving signals from the network, and a programmable signal processing module coupled to the transmitter and the receiver and adapted to be programmed from a remote station coupled to the network. The module can be programmed to perform at least one service or management function on the network.

Abstract: A communication system includes a transparent refractive optical wedge, a steerable mirror, a position feedback device, and a transceiver. The transparent refractive optical wedge has first and second faces angled with respect to each other and receives first and second optical signals through both the first and second faces. The first and second optical signals travel along parallel or common paths through the first face and diverge at a deflection angle with respect to each other through the second face. The steerable mirror is in optical communication with the first face of the optical wedge, the position feedback device, and the transceiver. The position feedback device adjusts a position of the steerable mirror to maintain the alignment of the reflected signal with the position feedback device. The transceiver has an optical transmitter transmitting one of the optical signals and an optical receiver receiving the other optical signal.

Abstract: We disclose a hybrid optical switch configured to switch optical channels based on their respective utilization factors. In an example embodiment, optical channels having relatively low utilization factors are unwrapped down to payload units, which are then switched electrically, e.g., using an Optical-Transport-Network (OTN) switch, in a manner that tends to increase the utilization factors of the optical channels that carry the switched payload units. In contrast, optical channels having relatively high utilization factors are switched optically, e.g., using a reconfigurable optical add/drop multiplexer, without being unwrapped. The hybrid optical switch may advantageously be deployed in a network node subjected to relatively high traffic-volume fluctuations because the switch tends to improve optical-channel utilization when the traffic volume is relatively low and to decrease the workload of the corresponding OTN switch when the traffic volume is relatively high.

Abstract: Optical transceiver sharing methods may be based on different ROADM node architectures for shared restoration in flexible grid optical networks. A ROADM node architecture with a pool of transceivers may improve transceiver utilization for backup optical paths, compared to a conventional ROADM node architecture. Sharing of transceivers in the pool for working and backup optical paths may further improve transceiver utilization. The methods disclosed herein may be used for multiple bit rates and different modulation formats.

Abstract: Embodiments of present invention provide an optical signal transportation system. The system includes a first and a second optical line protection (OLP) node; a working signal transmission medium and a protection signal transmission medium between the first and second OLP nodes providing transportation paths for an optical signal from the first OLP node to the second OLP node; and at least one digital dispersion compensation module (DDCM) connected to at least one of the working and protection signal transmission media inside the second OLP node, wherein the DDCM includes a plurality of dispersion compensation units (DCUs) with each DCU being capable of providing either a positive or a negative dispersion selected by an optical switch to the optical signal, and wherein the DDCM is capable of providing the optical signal a total dispersion determined by the optical switch of each of the plurality of DCUs.

Abstract: A non-linear distortion compensator includes: a first signal generator configured to generate a signal with a second multivalued level lower than a first multivalued level from an input signal; a non-linear distortion calculator configured to calculate non-linear distortion of the signal with the first multivalued level based on the signal with the second multivalued level generated by the first signal generator; and a non-linear compensator configured to compensate the non-linear distortion of the signal with the first multivalued level based on the non-linear distortion calculated by the non-linear distortion calculator.

Abstract: A dual-rate power point compensating circuit, comprising a microprocessor and a transmitter optical subsystem assembly (TOSA), wherein the TOSA includes a laser connected to a laser driver, a monitor photodiode (MPD) connected to the laser driver, and a current divider connected to the microprocessor and the MPD. When a feedback current from the MPD exceeds the adjustable and/or operating range of the laser driver, the feedback current is reduced so that it is kept in the adjustable and/or operating range of the laser driver. The laser driver determines the optical output power of the laser from the value of the reduced feedback current. The circuit and method extend the adjustable and/or operating range of a laser driver and enable it to regulate a target optical output power of the laser with a broad testing range and high accuracy when the feedback current is relatively high.

Abstract: Systems and methods for packet switching in a network, including two or more hybrid packet/circuit switching network architectures configured to connect two or more core level switches in the network architectures, the network architectures being controlled and managed using a centralized software defined network (SDN) control plane. An optical ring network may be configured to interconnect the two or more hybrid network architectures, and one or more hybrid electrical/optical packet/circuit switches configured to perform switching and traffic aggregation. One or more high-speed optical interfaces and one or more low-speed electrical/optical interfaces may be configured to transmit data.

Abstract: Embodiments of the invention describe polarization insensitive optical devices utilizing polarization sensitive components. Light comprising at least one polarization state is received, and embodiments of the invention select a first optical path for light comprising a first polarization state or a second optical path for light comprising a second polarization state orthogonal to the first polarization state. The optical paths include components to at least amplify and/or modulate light comprising the first polarization state; the second optical path includes a polarization rotator to rotate light comprising the second polarization state to the first polarization state.

Abstract: A coherent optical receiver includes: an attenuator that adjusts a power of an input optical signal; a mixer that mixes an optical signal output from the attenuator and local oscillator light; a photo detector that converts an optical signal output from the mixer into an electric signal; an amplifier that amplifies an output signal of the photo detector; a gain controller that controls a gain of the amplifier; a memory that stores dependence information that indicates a relation between an input optical power of an optical signal of a specified wavelength and a gain of the amplifier; and a controller that calculates an input optical power of the target wavelength based on a gain of the amplifier and the dependence information, and controls an attenuation amount of the attenuator based on the calculated input optical power, when a WDM optical signal is input into the coherent optical receiver.

Abstract: Flexible optical spectrum management systems and methods in an optical network including a plurality of interconnected network elements include determining an associated frequency/wavelength center and one or more bins for each of one or more traffic carrying channels on each of a plurality of optical fibers in the optical network; and managing the one or more traffic carrying channels on the plurality of optical fibers using the one or more bins of bins and the associated frequency/wavelength center, wherein at least one of the one or more traffic carrying channels comprises a coherent optical signal occupying a flexible spectrum on the plurality of optical fibers.

Abstract: In one embodiment, a method for multi-wavelength encoding includes receiving an input optical packet stream having an address and data and encoding the address of the input optical packet stream producing an encoded address including a first group of symbols including a first selected symbol, where the first group of symbols has more than two symbols. The method also includes generating a first wavelength in accordance with the first selected symbol and generating an output optical packet stream having the data of the input optical packet and the first wavelength, where the first wavelength corresponds to the first selected symbol. Additionally, the method includes modulating the first wavelength with the input optical packet stream.

Abstract: To enable signal position detection, frequency offset compensation, clock offset compensation, and chromatic dispersion amount estimation in a communication system based on coherent detection using an optical signal, even on a signal having a great offset in an arrival time depending on a frequency due to chromatic dispersion. An optical signal transmitting apparatus generates specific frequency band signals having power concentrated on two or more specific frequencies and transmits a signal including the specific frequency band signals. An optical signal receiving apparatus converts a received signal into a digital signal, detects positions of the specific frequency band signals from the converted digital signal, estimates frequency positions of the detected specific frequency band signals, and detects a frequency offset between an optical signal receiving apparatus and an optical signal transmitting apparatus.

Abstract: A method of setting up an end-to end connection between two end-points in an optical network. A plurality of validated paths in the network are defined. Each validated path extends between a respective pair of wavelength termination points and has requisite physical resources to carry signal traffic between its pair of wavelength termination points. A graph of the network is generated. An edge of the graph corresponds with a respective validated path, and a vertex of the of the graph corresponds with at least one wavelength termination point. The graph is analyzed to compute an end-to-end path between two vertices respectively corresponding with end-points of the end-to-end connection, and the end-to-end connection set up using the computed path.

Abstract: A planar lightwave circuit and an optical receiver which reduce degradation in signal quality is provided.

Abstract: A method for generating a switch fabric topology, comprising constructing a first switch fabric topology, modifying the first switch fabric topology to generate a second switch fabric topology, wherein modifying the first switch fabric topology comprises isolating center stage sets of the first switch fabric topology, and replacing each of the isolated center stage sets with a single × switching element to generate the second switch fabric topology, wherein is an integer representing a radix of the switching element determined in connection with the constructing of the first switch fabric topology.

Abstract: A distributed antenna system includes a master unit configured to receive at least one set of multiple input multiple output (MIMO) channel signals from at least one signal source. The master unit is configured to frequency convert at least one of the MIMO channel signals to a different frequency from an original frequency, and combine the MIMO channel signals for transmission. An optical link couples the master unit with a unit remote from the master unit for transceiving the MIMO channel signals. Conversion circuitry is configured to frequency convert at least one of the first and second MIMO channel signals from the different frequency back to an original frequency for transmission over an antenna.

Abstract: In one embodiment, a method for multi-wavelength encoding includes receiving an input optical packet stream having an address and data and encoding the address of the input optical packet stream producing an encoded address including a first group of symbols including a first selected symbol, where the first group of symbols has more than two symbols. The method also includes generating a first wavelength in accordance with the first selected symbol and generating an output optical packet stream having the data of the input optical packet and the first wavelength, where the first wavelength corresponds to the first selected symbol. Additionally, the method includes modulating the first wavelength with the input optical packet stream.