Abstract: An optical transceiver module which includes circuitry for detecting ambient light conditions in addition to circuitry for processing received optical data.

Abstract: A frequency-agile optical transceiver includes a shared local oscillator (LO), a coherent optical receiver and an optical transmitter. The LO operates to generate a respective LO optical signal having a predetermined LO wavelength. The coherent optical receiver is operatively coupled to the LO, and uses the LO signal to selectively receive traffic of an arbitrary target channel of an inbound broadband optical signal. The optical transmitter is also operatively coupled to the LO, and uses the LO to generate an outbound optical channel signal having a respective outbound channel wavelength corresponding to the LO wavelength.

Abstract: A method and system for modulating an optical signal to encode data therein. The method comprises the steps of directing the optical signal through a filter mechanism having a passband function including a center wavelength, and modulating the center wavelength of the optical signal to establish a difference between the center wavelengths of the filter mechanism and the optical signal to represent a data value. With the preferred implementation of the invention, a transmit device is used to encode the data in the optical signal, and a receive device is provided to decode the signal. The transmit device modulates the center wavelength of the optical signal to establish a difference between the center wavelength and a predefined wavelength to encode data in the optical signal, and the transmit device then transmits the optical signal. The receive device receives the optical signal from the transmit device and processes that signal to identify the encoded data.

Abstract: Systems and methods for regulating optical power are described. A system for regulating optical power includes a laser driver circuit that receives an enable/disable signal and a data modulator input. The enable/disable signal regulates asynchronous mode operation. The system also includes a laser module including a laser diode emitter and a photodiode detector. The laser module is coupled to the laser driver circuit and receives a laser bias current from the laser driver circuit. The system also includes a switch coupled to the photodiode to receive a signal from the photodiode detector. The system also includes an automatic power control (APC) feedback circuit that receives a signal from the switch and provides a laser bias current feedback signal to the laser driver circuit to compensate for power output changes in the laser diode emitter over time.

Abstract: An optical transmitter photonic integrated circuit (TxPIC) comprises a semiconductor monolithic chip with a plurality of optical signal channels where each channel comprises a modulated signal source. The output from the modulated signal sources are coupled to an input of an integrated optical combiner to form a WDM output signal for transmission off the TxPIC chip to an optical transmission link. An optical service channel (OSC) is also integrated on the TxPIC chip to receive a service signal from the optical receiver source which is also coupled the optical transmission link.

Abstract: A system and method for improving the transmission quality of a WDM optical communications system begins by determining the bit-error rate for an optical channel before forward error correction is performed at a receiver. The pre-corrective bit-error rate is fed back through a feed back circuit that includes a parameter adjustment module which adjusts an optical signal parameter based on the bit-error rate. As examples, the signal parameter may be a channel power, dispersion, signal wavelength, the chirp or eye shape of an optical signal. The feedback circuit may also adjust various parameters within the WDM system, including amplifier gain, attenuation, and power for one or more channels in the system. By adjusting these parameters based on a pre-corrective bit-error rate, transmission quality is improved and costs are lowered through a reduction in hardware.

Abstract: A tunable dispersion compensator whose passband center wavelength changes when the amount of dispersion compensation is changed is suitably adjusted. The relationship between temperature for keeping the center wavelength constant and the amount of dispersion compensation is stored in advance. After controlling the amount of dispersion compensation to achieve best or optimum transmission quality, the amount of dispersion compensation is converted into temperature in accordance with the stored relationship and, based on that, the temperature is controlled to keep the center wavelength constant.

Abstract: A system, device, and method for supporting cut-through paths in an optical communication system involves obtaining hop count and quality of service information by an initiating device and using the hop count and quality of service information by the initiating device to make decisions relating to a cut-through path. The hop count and quality of service information is provided in a reply message that is sent by a terminating device and modified by intermediate devices between the initiating device and the terminating device. The terminating device sends the reply with a hop count equal to one and quality of service information for a first link (hop) toward the initiating device. Each intermediate device increments the hop count in the reply and adds quality of service information for a next link (hop) into the reply.

Abstract: An Improved Infrared Signal Communication System and Method Including Transmission Means Having Automatic Gain Control is disclosed. Also disclosed is system and method that adjusts signal transmission power in response to incident signal power amplitude. The preferred system includes a control signal loop within the signal receiving system, and the system further includes a signal transmitting system that is responsive to the control signal loop. The preferred system includes manual, semi-automatic and automatic modes of operation. Still further, the preferred method includes at least two Ir-enabled appliances “stepping” each other “down” in transmit power in response to directives issued by the other Ir-enabled appliance.

Abstract: The invention is related to a method for equalizing performance of traffic channels in a WDM system where means for controlling transmitters (12), amplifiers (38) and receivers (14) are provided. Potentially, a number of channels are defined as loading channels (100). The method follows the steps of measuring the optical power at the input (48) of the amplifier (38), setting the power levels of a predefined number of loading channels (100) to a high power level, setting the power level of the traffic channels (200) to a power level less then the power level of the loading channels (100), adjusting the power level of the traffic channels (200), adjusting the power level of the loading channels (100), stabilizing the sum of the optical power measured at the optical amplifier (38), continuing the process for each channel the receiver lock signal (75) is sent back to the transmitters.

Abstract: A method is disclosed for monitoring and controlling the bit error rate (BER) in an optical communication network where an optical receiver in the optical transmission network is a monolithic photonic integrated circuit (RxPIC) chip. The method includes the steps of decombining on-chip a combined channel signal received from the network and then monitoring a real time bit error rate (BER) of a decombined channel signal. The determined BER is then communicated, such as through an optical service channel (OSC) to an optical transmitter source that is the source of origin of the channel signal. Based upon the determined BER, the chirp of a channel signal modulator at the optical transmitter source that generated the monitored channel signal is adjusted by, for example, adjusting its bias. The same channel signal received at the RxPIC chip can be monitored again to determine if an acceptable level for the BER has been achieved by the previous chirp adjustment.

Abstract: A FEC enhanced system for an optical transport or communication network that includes an optical transmitter that has a transmitter photonic integrated circuit (TxPIC) chip having an integrated circuit comprising an array of modulated sources providing a plurality of optical modulated channel signals comprising digital bit data streams where each signal is at a wavelength on a wavelength grid. The modulated channel signal outputs from the modulated sources are provided to an integrated multiplexer in the circuit to provide a WDM output signal at a circuit output. At least one FEC encoder is coupled to the modulated sources to encode error-correcting code containing redundant information of the data bit stream for each channel signal. An optical receiver in the network includes a receiver photonic integrated circuit (RxPIC) chip having an integrated circuit comprising an input to a demultiplexer and an array of photodetectors coupled to outputs of the demultiplexer.

Abstract: An optical transmission system includes an optical wavelength branching unit that shifts a wavelength transmission band in the short-wavelength or long-wavelength directions based on a branching filter operation temperature, and performs a branching operation on a wavelength-multiplexed signal. A reception transponder performs decoding on an error correction code. An error correction monitoring unit gathers an error correction amount upon which a branching filter temperature control unit sets the branching filter operation temperature. A transmission transponder performs encoding on an error correction code. An optical wavelength combining unit shifts the wavelength transmission band in the opposite direction from the shifting direction based on a combining filter operation temperature, to perform a combining operation on optical signals and output a wavelength-multiplexed optical signal.

Abstract: A data communications link uses a multi-power level optical source to encode and transmit data words along a communications channel to a receiver station. A received signal condition monitor senses the level of a pre-determined characteristic and transmits a control signal to a controller which controls the power output of the optical source.

Abstract: A scanning optical monitoring system and method are appropriate for high speed scanning of a WDM signal band. The system and method are able to identify dropped channels or, more generally, discrepancies between the determined or detected channel inventory and a perpetual inventory for the WDM signal, which perpetual inventory specifies the channels that should be present in the WDM signal assuming proper operation of the network. The system includes a tunable optical filter that scans a pass band across a signal band of a WDM signal to generate a filtered signal. A photodetector then generates an electrical signal in response to this filtered signal. A decision circuit compares the electrical signal to a threshold and a controller, which is responsive to the decision circuit, inventories the channels in the WDM signal.

Abstract: An optical multiplex communication system includes a transmission part and a receiving part, wherein the transmission part includes a transmission quality detecting part which measures and transmits a transmission quality information for the channels based on a request from the transmission part; the receiving part includes a variable optical attenuation part controls the optical signal level for the channels, an optical level setting part controls the variable optical attenuation part based on a setting value, a setting control part adding the setting value to the optical level setting part based on a request for setting.

Abstract: A method and system for automatically setting output power levels of optical transmitters in an optical communications arrangement. The optical communications arrangement includes at least a first and a second node, wherein the transmitter of the first node is optically coupled to a receiver in the second node, and the transmitter in the second node is optically coupled to a receiver in the first node. Respective sequences of power-level messages are transmitted from the transmitters to the receivers. Each power-level message indicates an output power level used by the transmitter to transmit the message, and each power-level message in a sequence is transmitted at an increasing power level.

Abstract: A module generally comprising a first transmitter, a detector and a controller. The first transmitter may be configured to transmit through a first physical channel of a connector. The detector may be configured to receive a first status signal but not receive user data through a second physical channel of the connector. The controller may be configured to adjust a power of the first transmitter in response to the first status signal.

Abstract: An optical transmission apparatus and method for changing a rise time (tr) and fall time (tf) of a signal light to be transmitted, to reduce wavelength dispersion characteristics and nonlinear effect of a transmission path. A transmitter includes a trtf adjusting circuit capable of adjusting tr and tf of a modulation signal so that the modulation signal is optimized in accordance with reception characteristics. A modulator then modulates a light with this adjusted modulation signal, and the modulated light is then transmitted to a receiver via a transmission path. Therefore, by transmitting the modulated light having changed tr and tf, the influence of wavelength dispersion characteristics and nonlinear effect of the transmission path can be offset, so that the waveform deterioration of signal light after transmission can be reduced.

Abstract: This invention relates to the zonal transmission of data by the modulation of the light output of arc lamps or discharge lamps; including the visible or invisible light output of fluorescent lamps, mercury vapor lamps, high or low-pressure sodium lamps, metal-halide based lamps, or other arc or discharge lamps. The method results in an easily installed, easily maintained, and economical to purchase, optical-wave communications system which exploits the existing infrastructure of a building or facility to facilitate the transmission of data in individual zones; thereby facilitating the transmission of wide-area as well as zonal-specific data to compatible receivers, and further facilitating the determination of location of remote devices or users, and the delivery or exchange of information or data, utilizing limited range transmission techniques.

Abstract: A system for managing signals in an optical network is provided. When a signal is originated by a source node for transmission to a destination node, the source node generates a message. Upon receiving this message, the destination node responds by sending an acknowledgment. Intermediate nodes examine these messages, allowing the nodes to obtain information which is used to take appropriate actions. A node is able to detect a switching event and the output power levels of signals leaving the node are maintained at a predetermined level. When transmission components transmitting a signal are powered up, a sequence of messages is exchanged, allowing the nodes to activate their transmission components in a sequential manner, avoiding signal level interference. Another sequence of messages is exchanged during protection line switching, allowing the nodes to adjust their respective transmission components in a sequential manner so as to avoid a “ringing” effect.

Abstract: According to the invention there is provided a method of controlling an optical communication system comprising an optical transmitter, an optical receiver and an optical fiber interconnecting the optical transmitter and the optical receiver, the method comprising determining the performance of the optical communication system and controlling at least one setting parameter of the optical transmitter according to the measured performance.

Abstract: Method and apparatus for time aligning first and second signals. The second signal is modulated by the first signal to provide a third signal. Frequency components of the third signal are then determined, the frequency components being indicative of time alignment between the first and second signals. The method and apparatus is particularly suitable for converting a Non-Return-to-Zero data signal to a Return-to-Zero data signal by modulating the Non-Return-to-Zero data signal with a Return-to-Zero pulse signal. The method and apparatus provides for the Non-Return-to-Zero data signal and the Return-to-Zero pulse signal being correctly time aligned in an automated manner without human intervention.

Abstract: An optical device including dynamic channel equalization is provided. In an exemplary multiplexer or line amplifier configuration the device includes a plurality of separate optical paths, each of which receiving a separate group of optical signals. Each group of optical signals is provided to an associated variable optical attenuator. Separate inputs of an optical combiner are each coupled to an output of an associated one of the variable optical attenuators. The optical combiner has an output providing the separate groups of optical signals in an aggregated form on an aggregate optical signal path. An optical performance monitor is coupled to the aggregate optical signal path, and is configured to detect an optical signal to noise ratio of each of the separate groups. The monitor supplied a feedback signal to corresponding ones of the variable optical attenuators for adjusting a respective attenuation associated with each of the attenuators in dependence of the detected optical signal to noise ratios.

Abstract: A performance monitoring method for an optically amplified transmission system. The method provides the optical power at each amplifier site, taking into account the inaccuracies introduced by the SRS in the power estimation obtained with the current methods. An optical spectrum analyzer is used at the output of the transmission link of interest to accurately measure the output power of each wavelength. This value is sent upstream to the last amplifier in the link, to compute an error term as the difference between the actual measurement and the estimation. The error term is used to infer the SRS-induced error by system elements not accounted for in the model. The error term is then fed-back to each amplifier in the link, so that the estimated power is adjusted to account for the SRS-induced inaccuracy.

Abstract: An optical transmission system for compensating for transmission loss includes a transmitting apparatus for serializing a plurality of n (n is a natural number)-bit channel data received from the outside in response to a predetermined clock signal, converting the serialized channel data and the predetermined clock signal into a current signal whose magnitude changes corresponding to an error detection signal, and outputting optical signals having optical output power corresponding to the magnitude of the current signal, a first optical fiber for transmitting the optical signals, a receiving apparatus for recovering the n-bit channel data and the predetermined clock signal from the optical signals received through the first optical fiber, detecting transmission loss generated when the optical signals are transmitted and received, optically converting the transmission loss, and outputting the optically converted transmission loss as the error detection signal, and a second optical fiber for transmitting the opt

Abstract: Disclosed herein is a terminal device including a photodetector, amplitude detecting circuit, light source, drive circuit, and control circuit. The photodetector receives a first optical signal. The amplitude detecting circuit detects the amplitude of an output from the photodetector. The drive circuit supplies a drive current to the light source so that the light source outputs a second optical signal. The control circuit decreases and increases the drive current according to an increase and decrease in the amplitude detected by the amplitude detecting circuit, respectively. In the case that this terminal device is used with another terminal device to construct a network, the dynamic range of the other terminal device can be reduced. Accordingly, the use of this terminal device can improve the extensibility of the network.

Abstract: A method and an arrangement for the employment of free space transmission systems for interruption-proof links between individual satellites of satellite communications systems by utilizing optical terminals. The communication link between two satellites is established in a reliable manner despite the presence of microvibrations.

Abstract: Disclosed is apparatus and method for establishing and maintaining optical data transfer between a first optical communications device (202) and a second optical communications device (204). The devices have a feedback communications link (216) therebetween. An optical signal (214), having a predetermined signal profile (306), is transmitted from a transmission source (104) within the first optical communications device to an optical receiver (112) within the second optical communications device. The predetermined signal profile is transmitted from the first device, via the feedback communications link, to the second device. The signal profile (408) of the optical signal as received by the optical receiver is determined, and compared with the predetermined signal profile to quantify any misalignment or movement of the optical signal with respect to the optical receiver.

Abstract: An optical communication system suitable for a coherent optical satellite communication is configured to include an optical transmission device having a laser signal generator, a first reference laser signal generator having a first local oscillating laser signal generator and an automatic frequency controller, an optical receiving device, and a second reference optical signal generator having a second local oscillating laser signal generator. The first reference local oscillating laser signal generator and the automatic frequency controller are used to generate a fixed beat reference optical signal, and thus the optical receiving device is capable of locking the transmitted laser signal according to the fixed beat reference laser signal in a way of heterodyne receiving so as to demodulate the transmitted signal frequency accurately and resolve the problem of laser frequency drifting.

Abstract: Optical transmission systems of the present invention include at least one optical amplifier generally including an optical signal amplifying medium supplied with pump power in the form of optical energy in via an optical pump source. The pump source includes multiple optical sources, at least two of which provide optical energy in first and second wavelength ranges separated by a frequency difference. The amplifier includes a wavelength controller configured to adjust the wavelength range of at least one of the optical sources to vary the frequency difference in a manner sufficient to vary optical intensity noise produced when the optical energy from the multiple optical sources is combined.

Abstract: The present invention provides an algorithm for partitioning a portion of a load between a FSOW link and a RF link in order to maintain a FSOW link. By having the ability to adjust the load between a FSOW and RF wireless link during inclement weather, the ability to maintain the FSOW link is significantly increased. The algorithm of the present invention uses the BER to determine the current atmospheric attenuation and whether or not a percentage of the load is to be partitioned to the RF link. Using the BER to determine the actual atmospheric attenuation provides a better characterization of the link status, than other techniques such as the difference between the transmitted and received power. Once such a determination is made, a control circuit is used to partition a percentage of the load from the FSOW link onto the RF link.

Abstract: A system and method for improving the transmission quality of a WDM optical communications system begins by determining the bit-error rate for an optical channel before forward error correction is performed at a receiver. The pre-corrective bit-error rate is fed back through a feed back circuit that includes a parameter adjustment module which adjusts an optical signal parameter based on the bit-error rate. As examples, the signal parameter may be a channel power, dispersion, signal wavelength, the chirp or eye shape of an optical signal. The feedback circuit may also adjust various parameters within the WDM system, including amplifier gain, attenuation, and power for one or more channels in the system. By adjusting these parameters based on a pre-corrective bit-error rate, transmission quality is improved and costs are lowered through a reduction in hardware.

Abstract: The present invention is a device to increase the bit rate and distance at which data can be transmitted by optical fiber. The device compensates the polarization dispersion of the line by processing a received optical signal with the use of a polarization controller, the generation of a differential group delay between two orthogonal polarization modes and a control unit for the polarization controller. The data that is sent is redundant to enable detection of errors affecting the data received and the control unit is adapted to minimize the error rate calculated in real time by using the redundant data. The application of the device is to long-haul optical transmission, in particular over stranded fibers.

Abstract: A correcting method of an optical signal transmission system that applies an optical signal generated by light-emitting action to an input end of an optical fiber and converts an optical signal arising at an output end of said optical fiber to an electrical signal by photo-electric conversion including: transmitting said optical signal by inputting said optical signal to said optical fiber and generating said electrical signal; and adjusting at least one of an electric current related to said light-emitting action and an electric current related to said photo-electric conversion according to an electric current of said electric signal.

Abstract: Method for wireless optical communication between a transmitting station and a receiving station, whereby the transmitting station provides a Request-to-Send (RTS) frame to the receiving station to announce the transmission of a data frame, the receiving station provides a Clear-to-Send (CTS) frame to the transmitting station in case of correct reception of the RTS frame, and the transmitting station subsequently sends the data frame to the receiving station. The RTS frame comprises Preamble (PA), Synchronization (SYNC), and Robust Header (RH) fields. The RTS frame further comprises a Source Address/Destination Address field (SA/DA) and a Cyclic Redundancy Check field (CRC). Adjusting the power level of the RTS frame to be different from the nominal transmission power level at which the data frame is sent, and by variable repetition coding within the Robust Header (RH) field of the RTS frame, allows a larger dynamic range of link quality estimation and improved collision avoidance properties.

Abstract: An Improved Infrared Signal Communication System and Method Including Transmission Means Having Automatic Gain Control is disclosed. Also disclosed is system and method that adjusts signal transmission power in response to incident signal power amplitude. The preferred system includes a control signal loop within the signal receiving system, and the system further includes a signal transmitting system that is responsive to the control signal loop. The preferred system includes manual, semi-automatic and automatic modes of operation. Still further, the preferred method includes at least two Ir-enabled appliances “stepping” each other “down” in transmit power in response to directives issued by the other Ir-enabled appliance.