Abstract: An apparatus, for use by an Optical Network Unit, performs receiving, from an Optical Line Terminal, a broadcast message including code set information indicating a first code set selected from a plurality of error correction code sets; determining whether the first code set is comprised in a group of code sets supported by the Optical Network Unit, wherein, the group of code sets includes at least one code set of the plurality of error correction code sets; and encoding an upstream transmission with the first code set, in case the first code set is included in the group of code sets.

Abstract: A first device receives a first container frame having a payload of a first length. The payload of the container frame includes multiple optical transport unit (OTU) frames, each of which includes an optical data unit (ODU) frame and a sequence of forward error correction (FEC) bits for the ODU frame. Each OTU frame is associated with a first sequence of error-identifying bits. The first device determines, for each OTU frame, a second sequence of error-identifying bits, and forms a second container frame including the OTU frames, the first sequences of error-identifying bits, and the second sequences of error-identifying bits. The first device transmits the second container frame to a second device.

Abstract: A transmission device includes a transmitter configured to output first monitoring signal light regarding monitoring control of the transmission device; and a switch that switches an output destination of the first monitoring signal light output from the transmitter to any one of a first transmission path or a second transmission path, wherein in the first transmission path, a first main signal is transmitted from the transmission device to another transmission device, and in the second transmission path, a second main signal is transmitted from the other transmission device to the transmission device.

Abstract: A system and method of storing and reading digital data, including providing a nanopore polymer memory (NPM) device having at least one memory cell comprising at least two addition chambers each arranged to add a unique chemical construct (or codes) to a polymer (or DNA) string when the polymer enters the respective addition chamber, the data comprising a series of codes; successively steering the polymer from deblock chambers through the nanopore into the addition chambers to add codes to the polymer to create the digital data pattern on the polymer; and accurately controlling the bit rate of the polymer using a servo controller. The device may have loading chamber(s) to load (or remove) the polymer into/from the deblock chambers through at least one “micro-hole”. The cell may be part of a memory system that stores and retrieves “raw” data and allows for remote retrieval and conversion. The cell may store multi-bit data having a plurality of states for the codes.

Abstract: A method and an apparatus for locating a fault cause are provided. The method includes: obtaining parameter values of a plurality of running parameters and a parameter value of a fault parameter in preset duration before a wavelength division multiplexing board device is faulty; determining a correlation between each of the plurality of running parameters and the fault parameter; and determining at least one target parameter from the plurality of running parameters based on a value of the correlation, where a correlation between each of the at least one target parameter and the fault parameter is greater than a correlation between the fault parameter and a running parameter other than the at least one target parameter in the plurality of running parameters. Accuracy of locating a fault cause can be improved in the embodiments of the present disclosure.

Abstract: Disclosed in some examples are methods, systems, optical devices, and machine readable mediums for blind detection model optimization. The receiver may monitor one or more optimization metrics to determine whether the optimization metrics meet an optimization condition. Once the optimization condition is observed, the system may perform a blind detection model optimization without utilizing a training sequence with the transmitters. That is, the detection models are optimized using normal data sent by the transmitters.

Abstract: An on-vehicle communication system mounted on a vehicle comprises a first switching device, a second switching device and a third switching device each including a first communication port and a second communication port. The first communication port and the second communication port of the first switching device are respectively connected to the first communication port of the second switching device and the first communication port of the third switching device, and the second communication port of the second switching device and the second communication port of the third switching device are connected to each other. Each of the first switching device, the second switching device and the third switching device measures a reception signal quality for the first communication port of the device itself and a reception signal quality for the second communication port of the device itself.

Abstract: The disclosure provides for a system that includes a plurality of stations equipped for free-space optical communications (FSOC) in a network and a central control system. At least one station in the plurality of stations includes a wavelength selectable switch, an OEO module, and one or more first processors. The one or more first processors are configured to control the wavelength selectable switch, process an electrical signal that is extracted using the OEO module, and communicate with the central control system. The central control system includes one or more second processors that are configured to receive data regarding FSOC communication conditions at the plurality of stations, determine a path between stations through the network based on the received data, and transmit instructions to the plurality of stations.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for optimizing PON efficiency using a variable FEC. In one aspect, an OLT broadcasts a message over an optical network, and receives, from an ONU, a response to the message. The OLT transmits activation parameters specifying that the OLT supports multiple different FEC code lengths when FEC is activated, and receives from the ONU, a set of FEC code lengths supported by the ONU. The OLT also receives performance measures collected by the ONU. The OLT selects, from among the FEC code lengths supported by the ONU, one or more appropriate FEC code lengths for communications between the ONU and the OLT based on the performance measures collected by the ONU and performance measures collected by the OLT. The OLT configures the ONU to utilize the appropriate FEC code length.

Abstract: A relay device transmits a frame received from any of a plurality of external devices that are connected via a plurality of communication lines. The external device is connected to one of the communication lines and to another one of the communication lines by searching a relay information table for specifying a relay destination of the frame. In the relay information table, information for identifying a frame type is stored in association with relay destination identifying information for identifying a communication line serving as a relay destination of a frame. The relay information table is partitioned into a plurality of sub-tables in accordance with priority based on the type identifying information or the relay destination identifying information. The relay device searches the sub-tables in descending order of priority using the type identifying information contained in the frame received from the external device as a search key specifying the relay destination.

Abstract: Method and apparatus are disclosed for robust visual light communication for vehicle-to-vehicle communication. An example vehicle includes a visual light communication (VLC) transmitter, a VLC communication receiver, and a VLC module. The VLC module sends a first handshake message including characteristics of the VLC transmitter and the VLC receiver using a first level of error correction. The VLC module also adjusts transmission parameters based on a received second handshake message. Additionally, the VLC module transmits data using a second level of error correction.

Abstract: The present invention provides a method of indirectly determining the optical signal-noise ratio of an optical fibre communications link. In a test environment, the relationship between OSNR and pre-FEC BER (forward error-corrected bit error rate) is determined for a particular type of optical transponder. When a transponder of that type is connected to an optical communications link then the pre-FEC BER can be measured and the OSNR inferred from the pre-determined OSNR-BER relationship. The OSNR value can then be used to select a transponder modulation format or other transmission parameters.

Abstract: A method and a transmitter for transmitting a pay load sequence are provided. The transmitter includes a ternary sequence mapper configured to map a binary data sequence to a ternary sequence stored in the transmitter, and a pulse shaping filter configured to generate a first signal based on the mapped ternary sequence. The ternary sequence includes elements of ?1, 0, and 1.

Abstract: The present disclosure provides a programmable integrated circuit die for optical testing. The integrated circuit die includes both photonic and electronic elements. In particular, the integrated circuit die may include a memory block, a programmable logic block (for example, a field programmable gate array), an electrical transceiver block, an optical transceiver block, and an optical test interface unit. The programmable logic block may be programmed to have logic functionalities of an embedded microcontroller and of various encoders/decoders. The logic functions may be soft, hard, or mixed. The memory may be used to store test patterns, look-up tables, measured waveforms, error time profiles and statistics. The electrical and optical transceivers may implement PAMn, NRZ, or QAMn modulations and may have programmable parameters, including: voltage levels; optical power; slew rate; magnitude/phase; clock generation and recovery; equalizations; sampling levels; and sampling times.

Abstract: The disclosure provides for a system that includes a plurality of stations equipped for free-space optical communications (FSOC) in a network and a central control system. At least one station in the plurality of stations includes a wavelength selectable switch, an OEO module, and one or more first processors. The one or more first processors are configured to control the wavelength selectable switch, process an electrical signal that is extracted using the OEO module, and communicate with the central control system. The central control system includes one or more second processors that are configured to receive data regarding FSOC communication conditions at the plurality of stations, determine a path between stations through the network based on the received data, and transmit instructions to the plurality of stations.

Abstract: A method of operating a BPSK modulator includes receiving an RF signal at the BPSK modulator and splitting the RF signal into a first portion and a second portion that is inverted with respect to the first portion. The method also includes receiving the first portion at a first arm of the BPSK modulator, receiving the second portion at a second arm of the BPSK modulator, applying a first tone to the first arm of the BPSK modulator, and applying a second tone to the second arm of the BPSK modulator. The method further includes measuring a power associated with an output of the BPSK modulator and adjusting a phase applied to at least one of the first arm of the BPSK modulator or the second arm of the BPSK modulator in response to the measured power.

Abstract: Aspects of the present disclosure generally relate to wireless communications. In some aspects, a device may receive information identifying a plurality of measurements of a communication metric related to a network at a plurality of time intervals. The device may determine a plurality of colors corresponding to a plurality of values of the communication metric. The plurality of values may correspond to the plurality of measurements of the communication metric at the plurality of time intervals. The device may combine the plurality of colors to generate a composite color for the communication metric.

Abstract: A network controller includes: a first acquisition unit configured to acquire, based on a signal quality amount of each of wavelength paths set in a network of an optical wavelength-multiplexed transmission system, a signal quality amount of each of spans in each of the wavelength paths; an arithmetic unit configured to calculate a signal quality amount of each of spans in a wavelength path of an estimation target, based on the signal quality amount acquired by the first acquisition unit; and an estimation unit configured to estimate a signal quality amount of the wavelength path of the estimation target, based on the signal quality amount calculated by the arithmetic unit.

Abstract: The present application is a detection system for locating and characterizing an object placed in a detection area in a three dimensional space. The detection system includes a plurality of magnetic field generators and magnetic field detectors arranged on opposite sides of the detection area and a control system for enabling generation of a magnetic field in the detection area by the magnetic field generators and for measuring of the magnetic field modified by the object at each of the magnetic field detectors. The detection system also includes a processor for processing the measured magnetic field to obtain a data set characterizing the object and a location of the object. The processor applies a reconstruction process on a predefined number of measurements of the modified magnetic field.

Abstract: Method and sensor system for measuring the transmission properties of a first transmission path based on feedback compensation between a first transmitter and a receiver, a compensation signal of a compensation transmitter being received in a superimposed manner in the receiver in addition to the emitted transmission signal of the first transmitter. A supply signal for the first transmitter and a receiver output signal each form a vector in a pre-Hilbert space. A Hilbert projection is performed between the receiver output signal and the supply signal so that a projection image signal is generated. An output signal is formed from the projection image signal. A pre-signal is generated by an inverse transformation of the output signal with the supply signal. A compensation signal for supplying the compensation transmitter is generated from the pre-signal formed in order to achieve feedback control of the receiver output signal.

Abstract: An optical transmission system includes: a plurality of optical transmission devices each including: an adjustment unit to adjust optical power of channels in the WDM optical signal; and a controller to control the adjustment unit based on an adjustment amount, and a management device including: a converter to convert an evaluation value for evaluating quality of service provided by using the channels in the WDM optical signal into a threshold value of transmission quality to be satisfied by the channels; and a determination unit to calculate the transmission quality of the channels based on monitoring information of the channels in the WDM optical signal adjusted by the adjusting unit of at least one of the plurality of optical transmission devices and to determine the adjustment amount to be set for the optical transmission device so that the calculated transmission quality of the channels satisfy the threshold value.

Abstract: Coverage and usage-based limitations to a wireless communications network can be estimated by monitoring network performance during a periods in which the network is relatively busy and relatively non-busy. For example, differences in distributions of bit error rates for calls in such time periods can be used to assess whether network limitations are associated with reduced-coverage zones or are usage-based. Such estimates can be used to target specific network features that limit network performance.

Abstract: An input bit error ratio estimating method executed by a communication control unit includes a computing, a condition determining, a first input BER estimating, a second input BER estimating, a third input BER estimating, and an input BER estimation result outputting. In the condition determining, the communication control unit determines which of a plurality of conditions set in advance to be narrowed down to one has been established, based on a post-internal decoding residual error detection ratio. Based on the condition that is determined in the condition determining as one that has been established, the communication control unit selects one out of a plurality of processing procedures for estimating the input BER, namely, selects one of the first input BER estimating to the third input BER estimating and executes the selected processing.

Abstract: An approach is provided for adjusting network interface metrics to optimize transmissions across a network. A measurement of performance of a network interface is made, wherein the network interface is configured to provide traffic across an optical network. A determination is made regarding whether the measured performance satisfies a predetermined threshold. A network metric value of the network interface is adjusted if the measured performance of the network interface satisfies the predetermined threshold.

Abstract: A WDM optical signal is transmitted through a tunable optical filter and is polarization-nulled to find optical signal to noise ratio of individual WDM channels. The polarization nulling can be performed using a heuristic multipoint extrema search method, such as Nelder-Mead method. A plurality of checkpoints can be included in the search to verify the progress and to improve the overall robustness of a real-time polarization nulling.

Abstract: A scheme is described of remote control of the slicing level of a receiver in a smart SFP (or SFP+, or XFP) duplex (or BiDi, or SWBiDi) transceiver in a communication system using an operating system with OAM and PP functions, an OAM, PP & Payload Processor, a transceiver, a BERT, and an optical link in the field.

Abstract: The present invention provides optical power adjustment method for EPON system, and OLT. The method comprises: OLT starting optical power adjustment procedure after ONU or ONT successfully registers, receiving upstream data from the ONU or the ONT (201); during optical power adjustment procedure, OLT detecting whether there is error code in upstream data; if not, notifying the ONU or the ONT to decrease transmission optical power progressively, during progressive decrease procedure, OLT continuing to detect whether there is error code in upstream data (203); if there is error code during progressive decrease procedure, notifying the ONU or the ONT to increase transmission optical power progressively, and during progressive increase procedure, OLT continuing to detect whether there is error code in upstream data (205); if there is no error code during progressive increase procedure, OLT stopping the adjustment (207).

Abstract: An apparatus and method of pre-emphasising a launch power profile of a section in an optical network is provided. The method comprises measuring the output power at the output of the section, determining the predicted output power associated with a flat launch power profile using design characteristics of the section and determining the total power deviation between the measured output power and the predicted output power. Also, the method comprises determining the signal to noise ratio deviation and the nonlinear phase shift deviation as a function of the total power deviation, and pre-emphasising the launch power profile based on a function of the calculated signal to noise ratio deviations of each span and the calculated nonlinear phase shift deviations of each span, such that the sum of the nonlinear phase shift deviations and the sum of the signal to noise ratio deviations of each channel are reduced by an equal amount.

Abstract: An optical communication system has a receiver that includes a plurality of photon counting sensors that each receive photons and generate pulses based on the received photons, and an electronic circuit that aggregates the number of pulses from the plurality of photon counting sensors into a merged pulse count. A demodulator samples the merged pulse count at predetermined time intervals to determine a number of photons received by the plurality of photon counting sensors during different sampling time intervals.

Abstract: A method and apparatus for adjusting a symbol decision threshold at a receiver in a communication network enables the receiver to be adapted to more correctly receive symbols as transmitted by a transmitter. In one embodiment, a received bit imbalance is detected by a receiver prior to error correction and after error correction to determine whether an error component of the received signal contains larger numbers of ones or larger numbers of zeros. Where the transmitter scrambles the signal prior to transmission, the receiver will also scramble the signal after error correction and prior to counting the number of zeros or ones. Any imbalance between the number of transmitted and received ones or zeros is used as feedback to adjust threshold values used by detectors to fine tune the manner in which the receiver interprets incoming signals.

Abstract: A system includes two optical modules that perform auto-setting of the optical links between the optical modules. One optical module sends an optical signal with a test pattern to the other optical module. If the receiving module determines that the test pattern is successfully received, it sends a pass indication to the transmitting module, and the transmitting module can configure its driver path in accordance with a transmit current setting used to transmit the test pattern. If the test pattern is not successfully received, the receiving module sends a fail indication, and the transmitting module can increase the transmit current setting and resend the test pattern. When the system includes multiple optical channels, one channel can be tested while feedback is provided on another channel. The system can iterate through all optical channels until they are all configured.

Abstract: Changes in a signal are detected. The signal is repeatedly sampled in a synchronous manner during a predetermined interval to generate a captured eye diagram. At least one of a positive differential eye diagram or a negative differential eye diagram is generated from the captured eye diagram and a baseline eye diagram. The at least one positive or negative differential eye diagram is analyzed to determine whether a change in signal conditions is present.

Abstract: One embodiment is a Poisson-based communication system. The system includes a receiver that comprises a photodetector that receives photons and generates pulses based on the received photons, a sampling event counter that counts the number of generated pulses by the photodetector and a demodulator. The demodulator samples the sampling event counter at predetermined time intervals to determine an occurrence of a first state when light pulse energy has been transmitted by a transmitter and received by the photodetector and an occurrence of a second state when light pulse energy has not been transmitted by the transmitter and received by the photodetector.

Abstract: An optical receiving device includes: an optical amplifier configured to amplify a wavelength multiplexed optical signal; a demultiplexer configured to demultiplex the amplified wavelength multiplexed signal into optical signals of a plurality of wavelengths; optical receivers configured to regenerate the demultiplexed optical signals; error correction units configured to correct a bit error in the regenerated optical signals; and main control unit. The control unit adjusts RXDTV of the optical receiver for receiving optical signals of a given wavelength to the optimal value in the state where the gain of the optical amplifier is lowered from that of a normal operation such that the occurrence of bit errors in the optical signals of the other wavelengths does not exceed the correction capability of the error correction unit.

Abstract: A system to provide carrier frequency control in an optical network includes a first network element monitoring performance information and a second network element coupled to the first network element by the optical network. The second network element receives performance information from the first network element using an administration channel bandwidth, and modifies a carrier frequency associated with the second network element based on the performance information such that the carrier frequency is aligned to a center of a signal channel bandwidth. A method of providing carrier frequency control includes transmitting performance information by the first network element to the second network element using an administration channel bandwidth, and modifying the carrier frequency by the second network element based on the performance information such that the carrier frequency is aligned to the center of the signal channel bandwidth.

Abstract: A manner of detecting the presence of alien devices, for example ONUs, that are transmitting upstream in an optical access network such as a PON. An alien detection device, for example a properly configured OLT, supports normal network operation and also monitors a selected performance characteristic. When the selected performance characteristic is evaluated to perform within satisfactory parameters, a protocol that includes a command to subscriber devices such as ONUs to go quiet, for example a rogue check, is executed and a signal detector monitored during the quiet period. An alarm may be generated if an alien device appears to be present.

Abstract: A method of transmitting a data signal using an optical transmitter of an optical communications system. A first encoder processes an N-bit input vector in accordance with a first mapping to generate a corresponding M-bit data stream. A Forward Error Correction encoder processes the M-bit data stream in accordance with a predetermined FEC encoding scheme to generate an encoded signal. A constellation mapper maps the encoded signal to symbol values in accordance with a predetermined modulation scheme to generate a corresponding symbol stream. A modulator modulates a carrier light in accordance with the encoded symbol stream to generate an optical signal for transmission through the optical communications system. The first mapping can be adjusted to maximize performance of the optical communications system.

Abstract: In one embodiment, an optical directional coupler includes an input terminal configured to receive an input optical signal and a first coupler optically coupled to the input terminal, where the first coupler has a first coupling length, and where the first coupler is configured to couple a first portion of the input optical signal to a first optical leg and a second optical portion of the input optical signal to a second optical leg. The optical directional coupler also includes the first optical leg, where the first optical leg is configured to phase shift the first portion of the optical signal to produce a first phase shift signal and the second optical leg, where the second optical leg is configured to phase shift the second portion of the optical signal to produce a second phase shift signal, and where the first phase shift signal has a phase difference relative to the second phase shift signal.

Abstract: There is provided a method for determining a signal transfer characteristic along a light path between a first point and a second point in an optical network. The optical network comprises at least one optical element situated in the light path. The method comprises transmitting a plurality of optical test signals of different bandwidths from the first point along the light path. Each signal has a known bandwidth and a known power. The method further comprises receiving the optical test signals at the second point after they have travelled along the light path and measuring the power of each received optical test signal. The method also comprises determining the signal transfer characteristic along the light path from the power measurements.

Abstract: An optical receiver includes a first discriminator in which an optimal point of a slice level is set and that compares a received signal to the slice level and discriminately outputs the received signal; a second discriminator that is connected in parallel to the first discriminator, compares the received signal to a slice level, and discriminately outputs the received signal; and a computing device that variably controls the slice level of the first and the second discriminators, respectively. The computing device executes a first process of setting the slice level of the first discriminator to be a predetermined slice level, calculating a pseudo error rate obtained when the slice level of the second discriminator is caused to variably scan, and setting the slice level of the first discriminator within a range in which the error rate does not vary.

Abstract: An optical packet switching apparatus includes an optical packet switching apparatus, an optical transmitting apparatus, and an optical packet receiving apparatus. The optical packet transmitting apparatus includes a packet generator for generating a packet signal by adding the routing information to a received client signal, a BIP adding unit for adding BIP to the generated packet signal, and an electrical-to-optical converter for converting the packet signal, to which the BIP has been added, into an optical packet signal so as to be sent out. The optical packet receiving apparatus includes an electrical-to-optical converter for converting the received optical packet signal into an electrical packet signal, and a BIP comparison unit for detecting the error occurrence in the packet signal, based on the BIP added to the packet signal.

Abstract: The invention proposes a system and method for selecting an optimal optical path through which to transmit an optical signal, the optimal optical path is one of a plurality of optical paths in a transparent optical network. Each of the plurality of optical paths includes a plurality of optical elements. For each of the plurality of optical paths, a first optical signal to noise ratio is determined for each optical element in the respective optical path. Then, for each of the plurality of optical paths, nonlinear distortions caused by each optical element in the respective optical path are modelled as Gaussian noise and a second optical signal to noise ratio associated with the modelled Gaussian noise is determined. Finally, the optimal optical path is selected using the sums of the first and second optical signal to noise ratios, respectively.

Abstract: Proposed is an efficient method of configuration of a transmitter and a receiver for realizing an optical transmission/reception module apparatus including at least one transmission wavelength and two or more reception wavelengths over a time division multiple access passive optical network or an optical network using multiple transmission/reception wavelengths. Further, proposed is a method of configuration of an apparatus which enables optical alignment and assembly in a single package by using a single lens and three different WDM optical filters for a reception module capable of receiving four wavelengths.

Abstract: A method for optimal combined 2R/3R regenerators placement for optical transmission includes determining an optimal placement of multiple 2R and 3R regenerators that minimizes bit error rate BER at a destination node, determining an optimal number of the 2R and 3R regenerators that minimizes a total cost while satisfying the BER at the destination node, and determining an optimal placement of the 2R and 3R regenerators along a route in the optical transmission.

Abstract: A border node of an optical network receives optical channel traffic parameter(s) associated with an optical channel from an optical channel originator external to the optical network. The received parameters are used to determine the suitability of at least one optical path within the optical network for an externally originating optical channel. If a suitable optical path is determined, an optical channel availability message indicating the availability at the border node of an optical path within the optical network for the optical channel is sent to the optical channel originator. The optical channel originator determines an available optical channel status of the optical channel from the received optical channel availability message for the optical channel.

Abstract: A bit error generating device includes a light source, an input device, and a control processor. The control processor includes logic configured to: receive protocol or bitrate information regarding a live traffic signal via the input device; determine bit error simulation signal parameters based on the received protocol or bitrate information; configure the light source to generate the bit error simulation signal based on the bit error simulation signal parameters; and instruct the light source to inject the bit error simulation signal into an optical fiber carrying the live traffic signal.

Abstract: A system and method is disclosed that allows for the monitoring, analyzing and reporting on performance, availability and quality of optical network paths. The correlation of PM parameter metrics to client connections, coupled with threshold-based alarm generation provides a proactive and predictive management, reporting and analyzing of the health and effectiveness of individual path connections to alert Operational Support (OS) staff and/or customers to signal degradation and impending Network Element (NE) failures. The system and method performs in real-time processing intervals required for alarm surveillance in a telecommunications network.

Abstract: A method includes generating a test signal and modulating the test signal. The method may also include transmitting the test signal on an optical path, where the optical path may include a number of add-drop multiplexer devices and amplifiers. The method may also include receiving the test signal at a destination device and converting the received test signal into an electrical signal. The method may further include identifying a portion of the electrical signal that is associated with the modulated test signal.

Abstract: In a passive optical network, a downstream transmission rate from an OLT to multiple ONTs can be optimized by matching a transmission scheme for frames addressed to a channel to the downstream transmission characteristics of the channel. An FEC coding can be made channel dependent so that channels with low error rates can use minimal protection, and therefore minimal overhead, while channels with high input bit error rates can use the level of FEC coding required to produce a desired output bit error rate.

Abstract: Methods and devices for laser driver calibration are disclosed. The methods and devices disclose determining first and second bit error rates for use in calibrating the laser driver. The methods and devices also disclose that if the first bit error rate associated with a first initial value is above a predetermined bit error rate, increasing the first initial value until the first bit error rate is not above the predetermined bit error rate, and if the second bit error rate associated with a second initial value is above a predetermined bit error rate, decreasing the second initial value until the second bit error rate is not above the predetermined bit error rate. In addition, the methods and devices disclose setting a calibrated parameter for the laser driver based, at least in part, on the increased first initial value and the decreased second initial value.