Abstract: An optical transceiver apparatus includes a gain medium, a photoelectric converter, at least one AWG, and a partial reflection mirror. The at least one AWG includes two common ports and multiple branch ports. One of the two common ports functions as a signal sending port, and the other functions as a signal receiving port, where bandwidth of the signal sending port is less than that of the signal receiving port. The gain medium and the photoelectric converter are connected to one of the branch ports of the AWG. The AWG and the partial reflection mirror are configured to cooperatively perform wavelength self-injection locking on an optical signal provided by the gain medium, and output the optical signal through the signal sending port. The AWG is further configured to demultiplex an optical signal received by the signal receiving port to a branch port. A WDM-PON system is also provided.

Abstract: A method and system for transient and switching stabilization of a fiber optic transport system. One or more data-bearing channels are coupled to an optical fiber. The data-bearing channels are distributed among a plurality of frequency sub-bands. A set of control channels is also coupled to the optical fiber. Each control channel includes a pair of signals at separate frequencies. There is at least one control channel in each of the plurality of frequency sub-bands. The pair of signals of a control channel are cross-polarized. Optical power in at least one of the plurality of sub-bands is measured. Responsive to the measured optical power, the optical power of a control channel is adjusted to maintain a substantially constant power of a sub-band that contains the adjusted control channel.

Abstract: An optical power monitor that detects optical power of respective wavelengths of a signal light in a wavelength multiplexing system, includes: a light emitter configured to superimpose a frequency modulation component on a signal light; a wavelength tunable filter configured to sweep a pass band of the signal light across a wavelength band for a signal light; and a detector configured to detect intensity changes in optical power passing through the wavelength tunable filter with a frequency modulation of the optical power, and to detect an optical power measurement value at a middle point of two points of the intensity changes of the optical power as the optical power of a wavelength to be measured.

Abstract: An optical transmission device includes a first power monitor to monitor a first signal into which second signals with respectively different wavelengths are multiplexed so as to measure received power of the first signal; an amplifier to amplify the first signal, to generate a third signal; a driver to drive the amplifier; a demultiplexer to separate the third signal into fourth signals with the different respectively wavelengths; second power monitors each to monitor each of the fourth signals so as to measure received power of each of the fourth signals; a memory to store therein data related to gain in the amplifier, the data corresponding to each of wavelengths of the second signals, with respect to parameters which are the received power measured by the first power monitor and driving condition; and a processor to calculate power of each of the second signals.

Abstract: The present invention provides a method and apparatus for automatically restoring node resource state in the Dense Wavelength Division Multiplexing Based Automatic Switched Optical Network (WSON) system. This method comprises the following steps: using each node in the WSON system as an initiation node and notifying the resource state of the initiation node to a neighboring node; the neighboring node comparing the received resource state of the initiation node with the resource state of the present end; and under the condition that the resource state of the initiation node and that of the neighboring node are inconsistent, according to the actual resource state, determining one of the initiation node and the neighboring node to be the node whose resource is occupied, and automatically releasing the resource of the node. The present invention also provides an apparatus for automatically restoring node resource state in the WSON system.

Abstract: The multi-channel optical device includes a demultiplexer in a laser cavity. The demultiplexer is configured to demultiplex a multi-channel light beam into a plurality of channels. The demultiplexer limits the wavelengths of the channels that are output from the laser cavity. The gain element includes quantum dots as the gain medium.

Abstract: A method of operating an optical amplifier includes determining a gain of the optical amplifier and providing a modulator drive signal to an optical signal source. The modulator drive signal is a function of the gain of the optical amplifier. The method also includes producing an input optical signal using the optical signal source. The input optical signal includes a first plurality of pulses, each of the first plurality of pulses having an amplitude related to the modulator drive signal. The method further includes coupling the input optical signal to the optical amplifier and amplifying the input optical signal using the optical amplifier to produce an output optical signal including a second plurality of pulses.

Abstract: In an Optical Add-Drop Multiplexer, a drop section comprises a Wavelength Selective Switch (WSS) having at least one drop-port, the WSS being operative to couple a respective set of w (where w>1) wavelength channels from a received Wavelength Division Multiplexed (WDM) signal to each drop port. A respective 1:s power splitter is associated with each drop port. Each power splitter supplies the respective set of channels received from its drop port to each one of a corresponding set of coherent receivers. Each coherent receiver operates to receive a selected one of the respective set of channels.

Abstract: A technique for providing time division multiplexing (“TDM”) and wavelength division multiplexing (“WDM”) communication services to customer premises (“CP”) over a passive optical network (“PON”) includes multiplexing a downstream TDM signal with downstream WDM signals onto a fiber trunk line coupled between a central office and a remote node (“RN”), separating the downstream WDM signals from the downstream TDM signal at the RN with a wavelength selective filter, power splitting the downstream TDM signal at the RN onto a plurality of fiber access lines as split TDM signals; and recombining each of the WDM signals with a corresponding one of the split TDM signals onto a corresponding one of the fiber access lines.

Abstract: An Optical Line Termination (OLT) system in a multi-wavelength Passive Optical Network (PON) includes a protection port for protecting a set of OLT ports without the use of a physical switch. The protection port has a tunable transceiver. The OLT system detects a failure of one of the OLT ports, which was originally adapted to transmit downstream traffic to a subset of ONUs on a downstream wavelength and to receive upstream traffic from the subset of ONUs on an upstream wavelength. In response to the detection, the OLT system tunes the protection port to the downstream wavelength for transmission and to the upstream wavelength for reception, and resumes communication between the OLT system and the subset of ONUs through the protection port instead of the OLT port.

Abstract: Modular kit of devices for variable distribution, mixing and monitoring of optical signals in the Internet and other networks is formed by an optical module interconnected with a control electronic module of the electronic system with two redundant power supply sources, which is subsequently interconnected with the communication computer module equipped with the user communication interface and the machine communication interface. Optical module has N optical inputs and M optical outputs where N and M are non-zero natural numbers, and in total the optical module contains N×M of 2×2 type Mach-Zender interferometer optical switching elements. Each of them has two optical inputs, two optical outputs and one electric input. Optical switching elements are mutually interconnected in a grid. Control electronic module is formed by N×M pulse-width modulators connected via an interface module to the communication computer module and to the power supply distribution block.

Abstract: There are disclosed systems and methods for detecting whether an Optical Network Unit (ONU) in a network may be causing a communications interference due to laser overlap. In one embodiment, an Optical Line Terminal (OLT) selects a pair of ONUs suspected of possibly causing laser overlap. The OLT then grants a first window to a first ONU for transmitting a first message, and grants to another ONU different from the pair of ONUs a second window for transmitting a second message. If the first message is not received by the OLT, then the OLT indicates that the first ONU may be causing laser overlap. In another embodiment, the OLT grants to an ONU a window for transmitting a message to the OLT. If the message is not received by the OLT when expected, then the OLT indicates that the ONU may be causing laser overlap. Other embodiments are disclosed.

Abstract: An optical network interconnect device interconnects a first WDM network for transmitting a WDM optical signal with first wavelength spacing and a second WDM network for transmitting a WDM optical signal with second wavelength spacing that is wider than the first wavelength spacing. The optical network interconnect device includes a filter to remove a wavelength component which is not used in the second WDM network from an WDM optical signal transferred from the first WDM network to the second WDM network.

Abstract: Novel tools and techniques that can be used to detect network impairment, including but not limited to impairment of optical fiber networks. In an aspect, such tools and techniques can be deployed at relatively low cost, allowing pervasive deployment throughout a network. In another aspect, such tools and techniques can take advantage of a “dying gasp,” in which a network element detects a sudden drop in received optical (or electrical) power, resolution, etc. at short time scales and sends a notification across the network before the connection is completely compromised. In yet another aspect, some tools can include a supervisory function to analyze aspects of the dying gasp with the goal to determine network segments associated with an impairment and an estimate of the location of an impairment within the network.

Abstract: A stabilized ultra-high bandwidth capacity transceiver system that combines an E-band (71-76 GHz, 81-86 GHz) millimeter wave RF transceiver with an eye-safe adaptive optics Free Space Optical (FSO) transceiver as a combined apparatus for simultaneous point-to-point commercial communications. The apparatus has a high degree of assured carrier availability under stressing environmental conditions. The apparatus establishes and maintains pointing and stabilization of mmW RF and FSO optical beams between adjacent line of sight apparatuses. The apparatus can rapidly acquire and reacquire the FSO optical carrier link in the event the optical carrier link is impaired due to adverse weather.

Abstract: An optical apparatus for use in an optical communications network, and a method of operating a network are described. The apparatus includes an input suitable for receiving a first continuous wave optical signal from a remote location on a network, and a modifying unit arranged to modify the first continuous wave optical signal to produce a second continuous wave optical signal having a wavelength which is different from the wavelength of the first continuous wave optical signal. A modulating unit is arranged to modulate the second continuous wave optical signal with data to produce a modulated second continuous wave optical signal.

Abstract: Methods, architectures, circuits, and/or systems for monitoring operating parameters and/or generating status indications associated with electronic device operation are disclosed. The method can include (i) monitoring a first operating parameter related to operation of the electronic device to determine a first parameter value, (ii) calculating a difference between the first parameter value and a predetermined value for the first operating parameter, (iii) monitoring a second operating parameter on which thresholds for operational warnings and/or alarms are based to determine a second parameter value, (iv) updating or changing the thresholds based on a predetermined change or event in the second parameter value, (v) comparing the difference to the updated or changed thresholds, and (vi) generating a corresponding one of the operational warnings and/or alarms when the difference crosses at least one of the thresholds in a predetermined direction.

Abstract: A polarization state of a transmission signal can be changed at a high speed based on a symbol-rate By switching a first switch, a second switch, and a third switch with time, one of an X-polarized wave_I-signal as a Y-polarized wave_I-signal, a signal caused by performing logical inversion for an X-polarized wave_I-signal, an X-polarized wave_Q-signal and a signal caused by logical inversion for an X-polarized wave_Q-signal is input to a second modulator. Further, by switching the first switch, the second switch and the third switch with time, the second modulator is input one of the X-polarized wave_I-signal as the Y-polarized wave_Q-signal, the X-polarized wave_I-signal, the signal caused by performing logical inversion for the X-polarized wave_I-signal, the X-polarized wave_Q-signal and the signal caused by performing logical inversion for the X-polarized wave_Q-signal. Thereby, a polarization state of a transmission signal can be changed at high speed based on a symbol-rate speed.

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: Plural optical communication apparatuses are connected through communication lines with a star topology to an optical coupler that is arranged at the center of star topology and can distribute input light. Each optical communication apparatus makes an optically transmitting unit input an optical signal into an optically inputting unit of the optical coupler, and makes an optically receiving unit receive an optical signal output from an optically outputting unit of the optical coupler, for detecting a collision based on the reception signal. After transmitting an optical signal from the optically transmitting unit, each of optical communication apparatuses makes the optically receiving unit receive the optical signal, performs the collision detection based on the comparison between the transmission signal and the reception signal.