Abstract: The present invention is provided with a first and second spindle at respective initial positions spaced apart by a predetermined distance and disposed linearly at both sides of inspection positions where the spindles are set for disk inspection, a disk inverting mechanism is provided at either the front side or the back side of the inspection position, at the same time when a disk fitted to the first spindle is transferred to the inspection position, a disk fitted to the second spindle is returned from the inspection position to own initial position, and at the same time when a disk fitted to the second spindle is transferred to the inspection position, a disk fitted to the first spindle is returned from the inspection position to own initial position, and the disk fitted to the first spindle which is returned to the own initial position is delivered to the disk inverting mechanism, thereby an inverted disk is fitted to the second spindle.

Abstract: In an optical signal monitoring method in wavelength multiplexing and an optical network, an area corresponding to a characteristic pattern of an eye pattern of an optical signal to be monitored, which characterizes a deterioration, is extracted from a database storing a map which associates a quality deterioration factor and deterioration amount of the optical signal with the characteristic pattern of the area of the eye pattern of the optical signal. The extracted pattern is collated with the map stored in the database to monitor the quality deterioration factor and deterioration amount of the optical signal, an occurrence time of a deterioration, duration of a deterioration, a deterioration occurrence cycle, and a deterioration duration cycle. An optical signal monitoring apparatus is also disclosed.

Abstract: A method for controlling an identification point for binarization processing in an optical signal receiver which can diminish a code error rate by optimally tracking an identification point at all times in accordance with a received signal, thereby maintaining transmission quality high. The method comprises identification point electrical signal increment/decrement steps. When the number of error correction operations is determined to have reached a target value in a target value arrival determination step, an identification point electrical signal is left unchanged. In contrast, when the number of error correction operations is determined not to have reached the target value, the identification point electrical signal is incremented or decremented within a predetermined increment/decrement range such that the number of error correction operations approaches the target value.

Abstract: In a communication apparatus and the like, the line diagnosis using a test signal is conducted with higher precision. A test signal transmitter generates a test signal for a line diagnosis to feed the signal to a test signal multiplexer. The multiplexer multiplexes the test signal with a main signal to deliver the resultant signal to a clock and data regenerator (CDR) module, a main signal transmitter, a main signal receiver, a test signal separator, and a test signal receiver that are arranged on a communication line through which the main signal is transferred. In the operation, a controller accomplishes a control operation such that the bit rate of the test signal is more than that of signals for communication to thereby intentionally cause bit errors. This improves precision in the measurement of the bit error rate required for the line diagnosis.

Abstract: A flash optical performance monitor for monitoring DWDM channels is disclosed. The monitor is to assess the spectral quality of an optical signal received and to determine from changes in the spectral quality, relative to a known spectral quality indicative of an acceptable signal, an estimate of signal quality. The flash optical performance monitor comprises a spectroemetric transducer for performing a spectral decomposition of the optical signal received, and for transforming the decomposed optical signal into electrical-domain data, a memory for storing advanced digital signal processing routines, and a processor in connection with the wavelength optical unit and with the memory. The processor receives the advanced digital signal processing routines and the electrical spectral data, and applies the advanced digital signal processing routines to the electrical spectral data. Also a method for monitoring a quality of data transmission of at least one optical channel is disclosed.

Abstract: An optical performance monitor (OPM) adapted to (i) sample an autocorrelation function corresponding to an optical signal transmitted in an optical network and (ii) based on the sampling, characterize two or more impairments concurrently present in the optical signal. In one embodiment, the OPM has an optical autocorrelator (OAC) coupled to a signal processor (SP). The OAC receives the optical signal from the network, generates two or more samples of its autocorrelation function, and applies said samples to the SP. The SP processes the samples and generates two or more signal metrics. Based on the signal metrics and reference data corresponding to the impairments, the SP then obtains a measure of each of the impairments.

Abstract: A method and a system for performing pre-emphasis of one or more optical channels respectively carrying one or more optical signals, by effecting bit rate of the one or more of the signals, thereby adjusting BER value thereof.

Abstract: A reception error rate controller in which the settling time can be shortened at the time of feedback control by controlling the quality of a received signal when the error rate is low. The reception error rate controller identifies the received signal by comparing it with a reference value, detects the error rate of the identified signal, controls the reference value based on the error rate and further controls the quality of the received signal based on the error rate.

Abstract: An optical apparatus comprises a phase comparator detecting a phase shift between a changing point of data transmitted through an electro/opto converter and a changing point of data received through an opto/electro converter, a delay controller and a variable delay circuit controlling a delay of the transmitted data so that the phase shift detected becomes equal to a value which minimizes a receiver sensitivity degradation due to crosstalks between a transmitter portion and a receiver portion.

Abstract: A method of controlling an optical signal receiver utilizes three control loops: a first control loop tunes the decision threshold of the receiver when the optical network is in a substantially steady state and a second control loop rapidly switches to a reference decision threshold upon the occurrence of an alarm condition. The invention rapidly switches to a predetermined reference decision threshold to compensate for optical signal changes in eye Q and received power after a protection switch or traffic reroute. After a protection switch, a slower tuning algorithm is used to adjust the decision threshold to a more optimum value. In the third control loop, the optical signal receiver may utilize a peak detector that detects the optical signal peak and a potentiometer that is commanded by a controller to output a commanded percentage of this peak value to adjust the threshold and thereby respond to transients.

Abstract: Two signal lights having different wavelengths are bidirectionally transmitted on an optical-fiber transmission-line. A Raman pump light source generates a first Raman pump light having predetermined wavelengths with a Raman gain-bandwidth for amplifying the first signal light and without response to the second signal light. Another Raman pump light source generates a second Raman pump light having predetermined wavelengths with a Raman gain-bandwidth for amplifying the second signal light and without response to the first signal light. The first Raman pump light and the second Raman pump light are differently injected from respective input/output terminals into the optical-fiber transmission-line by optical combining and branching filters.

Abstract: A bit-rate-transparent electrical space-division switching matrix is employed in an optical cross-connect and the input/output stage is constructed from simple, broadband optical receivers and transmitters. Since the switching matrix operates in unclocked manner, i.e. its switching function is not based on internal bit timing and frame timing, arbitrary signals can be switched though transparently at almost any bit rate, independently of the protocol-type being used. The inputs and outputs likewise operate fully independently of bit rate and protocol, since they only implement an O/E conversion or O/E conversion. By virtue of this structure, a simply constructed but extremely powerful optical cross-connect is created that can be employed equally for all types of optical signals within the stipulated wavelength-range.

Abstract: The delay setting of an optical delay line interferometer (DLI) used to decode differentially encoded phase shift keyed signals (DPSK or DQPSK) is controlled using a control signal representative of the ratio Perr2/Perr1 of the rate of occurrence of double errors and the rate of occurrence of errors. The ratio Perr2/Perr1, as the delay setting of the DLI is varied, exhibits a characteristic W-shaped structure consisting of a local maximum at the optimum value and two minima adjacent to the maximum, one on each side of it. This structure is present over a wide range of signal to noise ratio and residual dispersion.

Abstract: A method and system for handling information in a noisy environment in the form of at least one information carrying mode is disclosed. A plurality of encoded modes are generated by linear transformation of the information carrying mode, said encoded modes being provided on respective independent channels. The encoded modes are linearly combined to generate at least one decoded mode. A set of receiver channels is provided for receiving the decoded mode wherein one of said set of receiver channels is designated as a useful channel, and a useful signal is supplied as the decoded mode if it is received on the useful channel an discarded if it is received on the other receiver channels of the set, wherein the useful signal represents said information substantially uncorrupted by noise. The technique is applicable to quantum, classical or mesoscopic environments. The invention also provides a method and system for generating correlated states using a similar filtration technique.

Abstract: An apparatus for accelerating assessment of an optical transmission system using Bit Error Rate (BER) tests calculates Q-factors for at least two different extinction ratios from measured test BER values, and extrapolates to determine a Q-factor for an operational extinction ratio, whereby the operational BER value for the operational extinction ratio can be calculated.

Abstract: The present invention provides a fast testing system and method for optical transceiver, which integrates multiple testing machines in the testing environment for the optical transceiver, so that the user can employ the testing system for optical transceiver for rapid and simultaneous measurement of multiple products, and further improving the production efficiency. Moreover, with a combination of optical channel selector with a set of digital communication analyzer and spectrum analyzer, a plurality of products to be tested can be switched for parametric inspection, and by combining a tree coupler to synchronously transmit the measurement signals of the standard sample to the product to be tested in a multi-port transmission to further measure the bit error ratio. Thus, the product analysis report for the user is in real-time, so as to effectively improve the competitiveness of the industry.

Abstract: In a receiver operable in response to a data signal, an eye aperture size is detected along a time axis by an eye aperture detection circuit and is controlled by a control circuit so that it becomes a maximum. The eye aperture detection circuit determines different decision time points of the same level arranged along a time axis and judges whether or not an error is caused to occur at each of the decision time points, so as to detect the eye aperture size and to produce detection results. The control circuit processes the detection results in accordance with a predetermined algorithm to successively vary the eye aperture size and to keep the data signal at an optimum amplitude.

Abstract: A device (D) is dedicated to controlling the power of optical signals in a transparent switching node of an optical communication network that switches bands of wavelengths. The device includes, firstly, a controller (12) for comparing input optical power measurements to a selected first threshold and generating instructions representative of the comparison result, secondly, a measuring device (10A) for delivering measurements representative of the input optical power of the optical signals at one output at least of the switch (4), and thirdly, a processor between the switch (4) and the multiplexer (6) of the node and which control the optical power of the signals coming from the switch (4) as a function of the instructions they receive, so that the optical power of the signals at the input of the multiplexer (6) is maintained substantially constant.

Abstract: There is disclosed a method and computer program product for estimating a measure of the quality of the received signal in a computer simulation of an optical transmission system, wherein the simulation includes additive optical noise generated by components within the transmission system. The method and product are able to account for non-Gaussian statistics of noise fluctuations observed in the receivers of optical communications systems, in order to provide for the more accurate simulation of system performance than may be the case using prior art methods based on Gaussian approximation.

Abstract: An arrangement provides low cost path protection in an optical communications network. The arrangement has a portion 3 that provides (broadcasts) an outbound optical signal, and at least first and second transmitting portions 202, 206 transmit the outbound optical signal simultaneously onto at least first and second respective mutually distinct optical pathways 231, 232. Meanwhile, a selection arrangement 204 selects among plural incoming optical signals (via 1, 5) according to a SELECT control signal 228 to provide a selected signal, and an analyzer 222 analyzes characteristics of the selected signal to provide the SELECT control signal 228.

Abstract: Optical signals transmitted through an optical cable are converted into digital data of bits “1” and “0” on the basis of a reference voltage, and errors generated during transmission of the optical signals are corrected using Forward Error Correction (FEC). A method includes extracting numbers of occurrence of errors for bits “1” and “0” recovered through the FEC. Thereafter, the extracted numbers of occurrence of errors for bits “1” and “0” are compared with each other. A reference voltage used to judge levels of the signals to be level “1” or “0” is controlled if the numbers of occurrence of errors for bits “1” and “0” are not equal to each other. The current reference voltage is maintained if the numbers of occurrence of errors for bits “1” and “0” are rendered equal to each other.

Abstract: A monitoring system includes first and second evaluation sections for obtaining an averaged Q-factor parameter and a waveform distortion parameter from an optical signal amplitude histogram collected from optical signals under measurement. The monitoring system further includes a third evaluation section for determining both averaged Q-factor parameter and waveform distortion parameter, and for making a decision as to whether the main factor of the optical signal quality degradation is waveform distortion or not by comparing the averaged Q-factor parameter and waveform distortion parameter with their initial values or initial characteristics which are obtained when no optical signal quality degradation is present.

Abstract: A way of testing a wavelength division multiplexed (WDM) system without requiring connection to data source/sink equipment. A test signal is introduced onto a light path of interest in the system, and the test signal is monitored downstream for signal integrity. Lack of signal integrity is used to identify a fault in the lightpath. Alternatively, optical loopbacks may be used to localize and identify a fault in the lightpath. The lightpath includes a source optical node connected to a sink optical node via intermediate optical nodes. An optical signal introduced at the source node with a destination at the sink node may be looped back at any one of the intermediate nodes or the sink node to localize and identify a fault in the lightpath.

Abstract: It is disclosed that a method and apparatus that automatically monitors each channel's optical signal-to-noise ration (OSNR) using optical filter and polarization extinction method in wavelength division multiplexing (WDM) scheme-based optical transmission systems. OSNR is simply measured using optical filter by comparing amplified spontaneous emission (ASE) over the signal band, of which bandwidth has changed, while leaving signal intensity intact, with that original signal and, OSNR measurement is allowable over a wider range of OSNR by minimizing the ratio of signal to ASE over the signal band using polarization extinction method.

Abstract: This invention provides a technique for realizing low-cost optical signal waveform monitoring with improved realtimeness to be applied to signal quality monitoring in an actual optical transmission system, and a technique for stably controlling an optical transmitter/receiver and various compensators by means of this waveform monitoring. Opening/closing of a optical gate is controlled by means of a clock signal synchronized with an optical signal input from a photocoupler and having a period equal to the bit interval of data or N (N: a positive integer) times longer than the bit interval to allow each pulse of the optical signal for one bit of data to pass through the optical gate for only part of the time width of the gate. A photoelectric conversion element to which the optical signal transmitted through the optical gate for only part of the time width obtains an average light intensity of the input optical signal. Information on this average light intensity is output to a monitoring output section.

Abstract: An arrangement provides low cost path protection in an optical communications network. The arrangement has a portion 3 that provides (broadcasts) an outbound optical signal, and at least first and second transmitting portions 202, 206 transmit the outbound optical signal simultaneously onto at least first and second respective mutually distinct optical pathways 231, 232. Meanwhile, a selection arrangement 204 selects among plural incoming optical signals (via 1, 5) according to a SELECT control signal 228 to provide a selected signal, and an analyzer 222 analyzes characteristics of the selected signal to provide the SELECT control signal 228.

Abstract: A system (50) includes a communication path (170) and transmits data on a network (103, 106). A transmitter (101) transmits data on the network and a receiver (112) receives data from the network. A component (102, 114) in the communication path has a transfer characteristic (C1, C2, C3) adjusted in response to errors in data transmitted over and received from the network in order to reduce the error rate.

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: In a method of analyzing an optical communications signal, a threshold is established under control of a processor, and a decision circuit compares the amplitude of the signal to the threshold. A counter samples the output of the decision circuit and counts, over many periods of the signal, those samples indicating that the amplitude of the signal is above the threshold. The threshold generating, comparing, and counting are repeated for several thresholds within a range corresponding to an expected amplitude range of the signal. The stored counts and thresholds represent an amplitude histogram N(VT) for the signal. The derivative dN/dVT of the function N(VT) represents the probability density function (PDF) for the signal amplitude and can be used to derive performance information such as bit error rate and optical signal-to-noise ratio (OSNR).

Abstract: A method and system for multi-level power management in an optical network is provided. They include three levels of power management. The first level of power management dynamically changes equipment settings in each module of equipment so that required module setpoint values in each module are achieved. The second level of power management determines module setpoint values for each module of equipment within each node in the optical link so that required node setpoint values are achieved. The third level of power management determines node setpoint values at each node in the optical link so that the optical link meets predetermined power specifications. If any of the three levels cannot achieve the required setpoint values, an error signal is generated by that level of power management and sent to the level of power management above it, thus initiating a higher level of power management.

Abstract: If a repeater supervisory control (SV), a pre-emphasis automatic adjustment (PE), a receiving side threshold value automatic adjustment (Vth), a transmitting side dispersion compensation value setting (VDC(T)), and a receiving side dispersion compensation value setting (VDC(R)) are executed for an optical main signal, these controls are executed in the above described priority order. Accordingly, if the controls are independently executed, or if two or more controls simultaneously occur, a control with a higher priority is executed. In this way, a transmission quality of an optical signal is prevented from being badly influenced as a result that the controls are simultaneously executed.

Abstract: Link robustness, chromatic dispersion and polarization mode dispersion (PMD) immunity can be improved in fiber optical system by using a method for receiving an optical double sideband signal over an optical fiber system, comprising the steps of splitting the received optical double sideband signal into an upper sideband signal and a lower sideband signal, photodetecting the upper sideband and the lower sideband, equalizing the photodetected upper sideband signal and the lower sideband signal, and combining the equalized upper sideband signal with the equalized lower sideband signal. While PMD compensation is envisioned as a major application, one may also use the method and system for chromatic dispersion compensation or dispersion slope compensation in high bit rate systems, i.e. using dispersion compensation fiber (DCF) for coarse compensation and diversity receiver with electrical equalizer for fine tuning.

Abstract: A method for determining signal quality in optical transmission systems, wherein the effective signal-to-noise ratio is determined by measuring amplitude histograms of a signal and by calculating characteristic histogram moments and additional interference is ascertained by comparing the characteristic histogram moments with the optical signal-to-noise ratio.

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 transmission characteristic compensation system enables to reduce the generation of transmission deterioration by estimating an initially selected control direction, and also to compensate in advance with a setting value estimation so as to suppress the generation of transmission deterioration in advance. The transmission characteristic compensation control system includes a variable compensator having a control circuit; and an optimal setting value calculation portion for calculating an optimal setting value for the control circuit, wherein the optimal setting value calculation portion estimates future transmission deterioration on a predetermined time-by-time basis to set into the control circuit the optimal setting value for compensating the estimated transmission deterioration performed by the variable compensator.

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: A method and apparatus for optical performance monitoring that provides for multi-rate and multi-protocol monitoring includes, identifying a protocol associated with each of a plurality of communication signals using respective data rates extracted therefrom, determining, for each of the plurality of communication signals, a respective bit-error rate (BER), and generating an alarm indicative of BER excursions beyond a protocol appropriate BER threshold level.

Abstract: A method for validating a path through a switched optical network is disclosed. A bit error rate at the end of the path is determined. The path is validated if the bit error rate is within a predefined range.

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: In a line quality monitoring method of detecting a code error rate by identifying a received optical signal using different identification levels and executing bit comparison after identification, an amplitude of the signal and noise power contained in the signal are detected, and a difference between the different identification levels is controlled to be inversely proportional to the amplitude of the signal and to be proportional to the noise power of the signal. Alternatively, the amplitude of the signal is controlled to be constant and the difference between the different identification levels is controlled to be proportional to the noise power of the signal.

Abstract: A method and apparatus for dynamically managing power in a wireless interface device while maintaining an acceptable bit error rate. The wireless interface device includes a wireless interface unit, a bit error detection unit that monitors the bit error rate a data stream in the wireless interface unit, a processing unit, and a power management unit. The power management unit operates in a conjunction with the processing unit and the bit error detection unit to monitor the bit error rate and to dynamically adjust the voltage levels in the wireless interface unit to ensure that the bit error rate remains in an acceptable range.

Abstract: A data regenerator for regenerating a data signal, including a convertor for converting a received data signal into a binary data signal in dependence on conversion parameters, an error corrector for correcting errors in the binary data signal based on error correction code contained in the binary data signal to produce a corrected binary data signal, and a performance monitor for comparing the corrected binary data signal with an uncorrected representation of the binary data signal to determine information about the relative number of logic“1”s and logic “0”s that have been corrected by the error corrector and output a feedback signal representative of the relative number, wherein the convertor adjusts at least some of the conversion parameters in dependance on the feedback signal.

Abstract: A method for optimizing an optical transmitter is provided. According to one exemplary method, the optical transmitter is optimized by varying three transmitter parameters including the bias voltage, the crossing level and the peak-to-peak voltage. Once the respective optimal levels for the bias voltage, the crossing level and the peak-to-peak voltage are obtained, the optical transmitter is further checked to ensure that the optical transmitter is able to function properly within certain predetermined system parameters. The optical transmitter is also checked under two limiting scenarios to ensure that the optical transmitter is optimized against two predetermined lengths of optical fiber.

Abstract: A communication system capable of performing efficient Wavelength Division Multiplexing (WDM) transmission by flexibly handling connection services. A Bit Error Rate (BER) measurement unit measures BER of individual optical signals with different wavelengths. A BER transmission unit transmits BER information to the sending end. A wavelength assignment unit assigns each wavelength to at least one of high Quality-of-Service (QoS) communication and low QoS communication. A wavelength-assignment exchanging unit identifies low quality wavelengths with high BERs being used for the high QoS communication, and unless the low quality wavelengths being used for the high QoS communication outnumber the high quality wavelengths with low BERs being used for the low QoS communication, it exchanges the low quality wavelengths and an equal number of the high quality wavelengths. An optical signal transmission unit multiplexes the wavelengths to transmit the optical signals.

Abstract: Channels in an optical network that carry optical signals are evaluated using signal characteristics and suitable channels are compared to identify the channels that represent a single conversation using matching criteria. In another aspect, only channels that carry optical signals representing conversations of interest are compared.

Abstract: To improve the performance for measuring autocorrelation bit errors of optical signals to be measured, an autocorrelation-bit-error detection apparatus of the present invention using an optical branch system first has an optical branch unit for branching an optical signal to be measured into a plurality of branched optical signals, a plurality of light-to-electricity converters for converting a plurality of branched optical signals supplied from the optical branch unit into electrical signals, a plurality of decision circuits for deciding relations between the electrical signals supplied from the light-to-electricity converters and their threshold values, and a detector for detecting autocorrelation bit errors of the optical signal to be measured in accordance with comparison results between the decision circuits.

Abstract: An optical reception apparatus comprises an optical receiver to receive an optical signal from an optical transmission line, an error corrector to correct an error of the received signal and to transmit the error-corrected signal and error rate information before error correction, a judging apparatus to judge transmission quality of the optical transmission line according to the error rate information from the error corrector and a threshold value equal to an error rate lower than an error correction limit of the error corrector, and a selective breaker to transmit the signal whose error is corrected by the error corrector in normal state and to block transmission of the signal whose error is corrected by the error corrector when the judged result by the judging apparatus indicates deterioration of the transmission quality of the optical transmission line.

Abstract: The present invention is a bit error rate tester that may operate on network paths having devices that add or drop idles within a transmitted bit sequence. In particular, the bit sequence determines whether a received bit sequence is synchronized. If the received sequence is not synchronized or if a certain event/threshold is reached, then the bit error rate tester re-synchronizes the sequence prior to analysis. Also, the bit error rate detector is able to operate on high-speed networks and provide bit granularity measurements.

Abstract: An optoelectronic receiver having a variable transfer function to compensate for operational condition change. The receiver comprises a linear circuit having a tunable filter. A control circuit provides a signal to the tunable filter. The control circuit is connected to one or more sensors which sense one or more operational conditions. The control circuit signal is a function of the one or more sensed operational conditions. The control signal is input to the tunable filter which adjusts the linear circuit's transfer function based on the control signal. Further disclosed are an integrated circuit and optical communication system having the inventive optoelectronic receiver. A method for adjusting an optoelectronic signal in a receiver is also disclosed.