Abstract: A mobile terminal capable of localization, a localization server, and a method for localizing the mobile terminal using the localization server are disclosed. The disclosed localization server includes a control unit configured to control transmissions of visible-light signals from a multiple number of visible-light transmitting devices; and a position computing unit configured to compute a position of a mobile terminal based on time information regarding when the visible-light signals transmitted respectively from the plurality of visible-light transmitting devices were received at the mobile terminal, where the control unit controls the transmissions such that each of the plurality of visible-light transmitting devices sequentially transmits the visible-light signal for a particular first time period with no overlapping of transmission times of the visible-light signals transmitted respectively from the plurality of visible-light transmitting devices.

Abstract: An optical network includes a fiber optic link and one or more distributed block filter pairs. A given block filter pair includes a first block filter and a second block filter disposed at disparate locations along the fiber optic link. The first block filter of a respective pair is a bi-directional device that redirects optical carriers within a particular block wavelength range onto or off of the fiber optic link depending on a direction of the optical signals. The second block filter of a respective pair also is a bi-directional device that redirects carriers within the particular block wavelength range onto or off of the fiber optic link depending on a direction of the optical signal. The block filter pairs enable bi-directional communications over the fiber optic link between corresponding nodes disposed at different locations along the fiber optic link.

Abstract: Methods and apparatus to multiplex light signals are disclosed herein. An example method includes conveying a first light signal via a first optical path and conveying a second light signal via a second optical path. The example method also includes frequency-division multiplexing and time-division multiplexing the first light signal and the second light signal to enable generation of a multiplexed light signal. The example method further includes directing the multiplexed light signal into an optical detector.

Abstract: A method and devices for processing data in an optical network are provided, wherein a centralized component is connected to several decentralized components; wherein first data is conveyed from the centralized component to at least two decentralized components, wherein at least two decentralized components share an optical resource; and wherein second data is conveyed from the decentralized component to the decentralized component via at least one separate optical resource. Furthermore, a communication system is suggested comprising said device.

Abstract: An optical interface comprising a first portion having at least one optical conduit interface with a first axis for optically coupling with at least one optical conduit, a second portion having at least one transmitter interface with a second axis for optically coupling with a transmitting optical device, and at least one receiver interface with a third axis for optical coupling with a receiving optical device, the first, second and third axes being essentially parallel; and a wavelength filter element (WFE) disposed between the first and second portions, the WFE defining a first optical path between the transmitter interface and the optical conduit interface, and a second optical path between the optical conduit interface and the receiver interface.

Abstract: A method for measuring asymmetry in propagation delay of first and second links which connect a first node to a second node of a communication network. The method comprises measuring (101) a round trip delay of the first link. The round trip delay can be measured by transmitting (102) a test signal from the first node to the second node over the first link and receiving a reply to the test signal from the second node over the first link. The method further comprises measuring (105) a round trip delay of the second link. The round trip delay can be measured by transmitting (106) a test signal to the second node over the second link and receiving a reply to the test signal from the second node over the second link. A difference in the propagation delay of the first link with respect to the second link is determined (109) using the measured round trip delays of the first link and the second link.

Abstract: An optical system may include a digital signal processor (DSP) to receive first samples of a digital signal. The first samples may be Hamming encoded. The DSP may correlate the first samples to multiple groups of second samples to determine multiple correlation values. Each of the multiple groups of second samples may correspond to respective code words. Each of the multiple correlation values may correspond to a correlation measurement between the first samples and each of the multiple groups of second samples. The DSP may determine a particular code word, of the multiple code words, corresponding to one of the correlation values of the multiple correlation values; determine output bits based on bits of the particular code word and the one of the correlation values; and provide the output bits. The output bits may include data associated with the digital signal.

Abstract: An implanted microphone is provided that allows for isolating an acoustic response of the microphone from vibration induced acceleration responses of the microphone. The present invention measures the relative motion between a microphone diaphragm, which is responsive to pressure variations in overlying media caused by acoustic forces and acceleration forces, and a cancellation element that is compliantly mounted within a housing of the microphone, which moves primarily in response to acceleration forces. When the microphone and cancellation element move substantially in unison to acceleration forces, relative movement between these elements corresponds to the acoustic response of the microphone diaphragm. This relative movement may be directly measured using various optical measuring systems.

Abstract: A digital signal processor (DSP) may receive samples of a signal from an analog-to-digital converter (ADC); convert the samples from a time domain to a frequency domain; determine a clock phase error of the samples while in the frequency domain; and provide a voltage corresponding to the clock phase error. The voltage may be provided to reduce timing errors associated with the samples.

Abstract: An optical signal quality monitoring apparatus includes an optical detector for directly receiving an optical signal modulated in an optical path and converting the optical signal to an electric signal, an asynchronous sampling unit for asynchronously sampling the electric signal of the optical detector at a reduced speed, and a digital signal processor for monitoring an optical signal quality by finding a synchronized amplitude histogram of data sampled in the asynchronous sampling unit. An optical signal quality monitoring method includes (a) a step of allowing an optical detector to directly receive a modulated optical signal and to convert the optical signal to an electric signal; (b) a step of allowing an asynchronous sampling unit to asynchronously sample the electric signal; and (c) a step of allowing a digital signal processor to monitor an optical signal quality by generating a synchronized amplitude histogram of sampled data.

Abstract: The present invention provides a data cross-connect system and method. The data cross-connect system comprises: at least two first stage cross-connect modules, at least one second stage cross-connect module and at least one third stage cross-connect module; the first stage cross-connect module comprises: a first stage cross-connect sub-module, a signal packaging sub-module, a first information generation sub-module and at least one transmitter. The present invention allows high rate interconnection between subracks, therefore the number of interconnecting optical fibers and connectors of the optical fibers can be reduced; in addition, the second stage cross-connect module applies cross-connecting directly in the optical layer, hence the number of cross-connect subracks can be reduced and the size and power consumption of the cross-connect subracks can also be reduced.

Abstract: The optical signal to noise ratio is improved when the polarization multilevel signal light is demodulated. A optical polarization multilevel signal receiving apparatus is provided with a polarization multilevel receiver configured to generate at least one estimation symbol A1 to AN estimating a state of the symbol A by utilizing a polarization state of at least one polarization multilevel symbol received in a past before the symbol A, a past value of a decision variable, and a decision result, average the estimation symbols A1 to AN and the symbol A to calculate a reference symbol Ar, and use the calculated reference symbol Ar in place of the symbol A to calculate a decision variable corresponding to a polarization state change of the received symbol R, where R is a received symbol and A is at least one past symbol used as a reference for a change.

Abstract: A small form factor pluggable (SFP) device has an embedded optical time domain reflectometer (OTDR) for detecting anomalies along an optical fiber. The SFP device has a plurality of optical subassemblies (OSAs) that are used to transmit an optical data signal at a first wavelength, transmit an optical OTDR signal at a second wavelength, and receive an optical data signal at a third wavelength. The OTDR signal is effectively isolated from the data signals based on wavelength, and samples of returns of the OTDR signal are analyzed to detect at least one anomaly along the optical fiber.

Abstract: An optical transmitter may include an optical source to provide a first optical signal having a varying frequency; an optical circuit to receive a portion of the first optical signal and provide a second optical signal corresponding to a change in frequency of the first optical signal; a photodetector to receive the first optical signal and provide an electrical signal that is indicative of the change in frequency of the first optical signal; an integrator to receive the electrical signal and provide an inverted electrical signal; and a controller to process the inverted electrical signal and provide a current, associated with the inverted electrical signal, to the optical source. The optical source may reduce the phase noise associated with the first optical signal based on the current.

Abstract: An optical communication system that connects a plurality of user-side optical line terminating apparatuses (hereinafter referred to as ONUs) to a station-side optical line terminating apparatus (hereinafter referred to as OLT) using a common optical fiber, wherein the ONU as at least a part of the ONUs includes a transceiver having a power saving function for inactivating a transmitting unit while supplying electric power to a receiving unit and a control apparatus that transmits support information of the power saving function to the OLT via the transceiver, and the OLT includes a control apparatus that generates transmission allowance information of upstream communication based on the support information of the power saving function and a transceiver that receives the support information of the power saving function and transmits the transmission allowance information to the ONU.

Abstract: An integrated optical phased array includes an input channel receiving an optical input signal, and a multitude of signal processing channels each adapted to supply an associated optical output signal along a first axis in response to the input signal. Each signal processing channel includes, in part, a phase modulator adapted to modulate the phase of the signal travelling through the channel, thereby to control or steer the output signal of the phased array. Each channel optionally includes first and second photo detection circuits respectively generating first and second detection signals. The first and second detection signals in each channel may be used to modulate the amplitude and/or phase of the output signal of that channel thereby to control and steer the output signal of the phased array.

Abstract: The present invention relates to a passive wavelength division multiplexing device for automatic wavelength locking and a system thereof including an optical multiplexer, an optical filter, an integrated optical receiver monitor, and a tunable optical transmitter. Through wavelength locking that adjusts a wavelength of an optical signal, which changes according to an external environment such as a temperature change, into a wavelength of an optical signal having the maximum optical intensity, communication quality may be maximized by securing a stable communication channel, a locking time and a communication channel setting time may be reduced, and more robust locking may be guaranteed.

Abstract: A tunable optical transmitter, comprising a tunable laser comprising a distributed Bragg reflector (DBR) section, a phase section, and a gain section, a photodiode detector (PD) optically coupled to the tunable laser, wherein the tunable optical transmitter lacks a temperature controller, and wherein the tunable optical transmitter is configured to lock onto a wavelength at different operating temperatures.

Abstract: A transmission apparatus includes a package that has a plurality of slots into each of which a board can be freely detachably inserted; at least one control board; a PWE interface communication unit that is connected to the control board, converts an input SDH or PDH signal to a packet signal, and outputs the converted signal to the control board; a radio transmission communication unit that is connected to the control board, converts the packet signal to a radio signal, and outputs the converted signal; and an optical transmission communication unit that is connected to the control board, converts the packet signal to an optical transmission signal, and outputs the converted signal. The units are separately inserted in the slots.

Abstract: An IP switching system that includes a coder/decoder configured for converting voice between analog and digital; and a first switch coupled to the coder/decoder configured to isolate non-secure entities in a network and comprising a plurality of fiber optic ports; wherein two of the plurality of fiber optic ports are configured to pass classified and unclassified data to one of a classified IP network and an unclassified IP network; and wherein the first switch is configured to operate in a plurality of states including secure, non-secure, and configuration/cut-off. The IP switching system also includes at least one controller connected to the coder/decoder via the first switch such that the at least one controller is accessible to the coder/decoder only when the first switch is in the configuration/cut-off state; wherein the at least one controller is configured to store and retrieve sensitive coder/decoder parameters for operation of the coder/decoder.