Entries |
Document | Title | Date |
20080292322 | OPTOELECTRONIC DEVICES WITH INTELLIGENT TRANSMITTER MODULES - An optoelectronic device can implement an intelligent transmitter module (“ITM”), rather than a conventional TOSA, for the transmission of optical data signals. The ITM can include an optical transmitter, a CDR and driver IC, and a microcontroller and/or linear amplifier. Space available in the optoelectronic device due to using an ITM rather than a TOSA and PCB-bound CDR, driver, microcontroller, and/or linear amplifier can be used for the inclusion of one or more electronic and/or optical components. Electronic components that can be included in a device with an ITM include: an FPGA, a DSP, a memory chip, a digital diagnostic IC, a video IC, a wireless interface, and an RF interface. Optical components that can be included in a device with an ITM include: a VOA, an SOA, a MUX, a DEMUX, a polarization controller, and an optical power monitoring device. | 11-27-2008 |
20090123165 | Dispersion compensating apparatus - A dispersion compensating apparatus compensates dispersion of an optical signal using reflection-type etalons. Each of the etalons reflects the optical signal and at least one etalon has, with respect to a group delay characteristic, a wavelength cycle and a finesse that are larger than those of the other etalons. Power supplies and temperature control units respectively shift, in terms of the wavelength, the group delay characteristics of the etalons. | 05-14-2009 |
20090142073 | METHOD AND APPARATUS FOR MAINTAINING A COHERENT COMBINED BEAM DURING ARBITRARY STEERING - A method and apparatus for accounting for phase differences in a transmit path of an optical system is provided. A transmit control system nullifies phase errors in signals propagating from a coherent source to phase samplers and back to a transmitter sensor. A small time-dependent length modulation is applied to a feed fiber of each aperture and this modulation enables a hill-climbing servo loop to increase, or in some cases even maximize, a detected intensity. This results in a particular relationship between the phases at all the phase-sampling points. The optical system is then calibrated so that this relationship corresponds to in-phase beams when the optical system is aimed at boresight. | 06-04-2009 |
20090238580 | PRE-EQUALIZED OPTICAL TRANSMITTER AND PRE-EQUALIZED OPTICAL TRANSMISSION SYSTEM - Provided is a pre-equalized optical transmitter, comprises: a laser source; a duo-binary pre-coder circuit; a pre-equalization circuit for applying an inverse function of chromatic dispersion; at least two D/A converters; and an optical field modulator comprising at least two input terminals for an electric signal. The pre-equalized optical transmitter: converts, by the duo-binary pre-coder circuit, a digital information signal of a predetermined symbol time to be transmitted into a digital complex signal including one sampling point per symbol; equalizes, by the pre-equalization circuit, degradation in transmission of the digital complex signal; converts, by the D/A converters, the equalized digital complex signal into an analogue signal; suppresses an analogue signal leaking outside a Nyquist bandwidth by at least 23 dB; modulates, by the optical field modulator, light output from the laser source with the analogue signal to generate a modulated optical field signal; and transmits the modulated optical field signal. | 09-24-2009 |
20100092184 | Active Linear Amplifier Inside Transmitter Module - In one example embodiment, a transmitter module includes a header electrically coupled to a chassis ground. First and second input nodes are configured to receive a differential data signal. A buffer stage has a first node coupled to the first input node and a second node coupled to the second input node. An amplifier stage has a fifth node coupled to a third node of the buffer stage and a sixth node coupled to a signal ground that is not coupled to the chassis ground. An optical transmitter has an eighth node coupled to a seventh node of the amplifier stage and a ninth node configured to be coupled to a voltage source. A bias circuit is configured to couple a fourth node of the buffer stage to a bias current source. | 04-15-2010 |
20100098436 | METHOD AND APPARATUS FOR GENERATING SIGNALS WITH INCREASED DISPERSION TOLERANCE USING A DIRECTLY MODULATED LASER TRANSMITTER - An optical transmitter is disclosed wherein a signal processor receives a data stream and outputs a drive signal for a laser, where the drive signal encodes each bit of the data stream according to the values of adjacent bits effective to compensate for spreading of bits within the fiber. The output of the laser is input to an optical spectrum reshaper that outputs a signal having an enhanced extinction ratio. | 04-22-2010 |
20100135675 | LASER DIODE DRIVER DRIVEN IN SHUNT MODE BY SIGNALS COMPLEMENTARY TO EACH OTHER - A laser driver to drive an LD in the shunt mode and driven with signals complementary to each other is disclosed. The driver includes two FETs of the enhancement and a terminator. Two FETs are connected in parallel with the LD and driven by the complementary signals but have sizes different from each other. The terminator is connected between respective gate terminals of the FET. The driver further includes a capacitor that compensates the difference in the size of two FETs, which is substantially equal to a magnitude of the junction capacitance of the FET. The capacitor is integrated with the FETs. | 06-03-2010 |
20100150578 | OPTICAL TRANSMISSION DEVICE - An optical transceiver includes an optical transmitter. The optical transmitter varies the wavelength of its output beam in accordance with the setting of a digital to analog converter. Two split beams emerging respectively from beam splitters are introduced into a photodetector and a wavelength filter, respectively. A quotient is calculated by dividing the digital value output from an analog to digital converter (ADC) by the digital value output from another ADC. A memory address m is then determined based on this quotient without making any calculation for compensating for the imperfect characteristics of the wavelength filter. A wavelength notification value is then selected from a wavelength notification table based on the determined memory address m, and sent to the system host. | 06-17-2010 |
20100166437 | Optical detecting circuit, optical transmitting apparatus, and optical detecting method - An optical detecting circuit includes a PD receiving unit generating voltage depending on an optical level of input light, a high range amplifying unit amplifying the generated voltage, a low range amplifying unit amplifying the generated voltage by a gain larger than that of the high range amplifying unit, an A/D converting unit digitizing voltage levels of the output voltages of the high range amplifying unit and the low range amplifying unit, a selecting unit comparing the A/D conversion results with thresholds to select for output one of the digitized values of the voltage levels of the output voltages of the high range amplifying unit and the low range amplifying unit, and an output correcting unit obtaining a correction value depending on the selection result from a correcting table to add the correction value to the value selected by the selecting unit. | 07-01-2010 |
20100183317 | INFRARED TRANSMITTER - An infrared transmitter transmits a signal via an infrared ray. The infrared transmitter includes: a signal converter for converting the signal into an infrared signal; an oscillator for oscillating a carrier frequency of the infrared signal; a controller for adjusting a cutoff frequency of a filter according to the carrier frequency; and the filter provided between the oscillator and the signal converter to reduce a spurious signal of a carrier wave. The cutoff frequency of the filter is adjusted by the controller. | 07-22-2010 |
20100272447 | Signal detection for optical transmitters in networks with optical combining - Signal detection for optical transmitters in networks with optical combining. Presented herein is a multi-faceted means for performing electrical to optical conversion such as in an optical transmitter as implemented within a communication system including at least some optical communication links therein. The turning on and turning off of a light source (e.g., a laser diode (LD), a light emitting diode (LED), and/or other component that performs electrical to optical conversion) is performed in accordance with a number of operational parameters. Some communication systems include multiple optical links (e.g., multiple fiber-optic links) from multiple transmitters that connect to a common receiver. In addition, some optical transmitters include multiple electrical links (e.g., multiple electrical communication links) from multiple communication devices that connect thereto. | 10-28-2010 |
20100290790 | TUNABLE PHOTONIC INTEGRATED CIRCUITS - Photonic integrated circuits (PICs) may include transmit and receive PICs that include individually tunable optical elements. In one implementation, a device may include a number of optical elements that form a number of optical channels. Tuners may be used to modify a property associated with the at least one of the optical elements where the modified properties of the optical elements adjust a frequency grid of the optical channels. | 11-18-2010 |
20110164885 | METHOD TO CONTROL TEMPERATURE OF LD - New method to control the optical transmitter is disclosed. The optical transmitter provides both of the ATC feedback loop and the APC feedback loop. When a failure occurs in the ATC feedback loop and the temperature sensor is unable to output an adequate signal any longer, the optical transmitter cuts the APC loop and operates the LD in constant conditions. The output of the monitor PD is transferred to the ATC loop to control the TEC based on the optical output of the LD. | 07-07-2011 |
20110206384 | BIAS CONTROL IN AN OPTICAL MODULATOR AND TRANSMITTER - An apparatus and method for controlling bias in an optical modulator is disclosed. The method is particularly applicable to controlling multi-wavelength modulators and wavelength-tunable transmitters. At a calibration stage, a desired optical performance of the modulator is achieved, and an amplitude of a peak-to-peak variation of the output optical signal at a pre-determined amount of dither is stored in a memory as a reference. At operating stage, a controller of the optical modulator adjusts a bias voltage of the modulator until the measured peak-to-peak optical signal variation matches the reference value stored at the calibration stage. For multi-wavelength modulators and tunable transmitters, the calibration is repeated at each wavelength, and corresponding peak-to-peak optical signal variations are stored in the memory. | 08-25-2011 |
20110293290 | Multimode Optical Fibers - A multimode optical fiber has an equivalent modal dispersion value (DMD | 12-01-2011 |
20120288285 | VARIABLE DISPERSION COMPENSATOR - Exemplary methods and systems for applying a correction to an initiated signal are disclosed. In some examples the correction may be a compensation for dispersion present, e.g., in an optical signal. An exemplary method may include receiving an initiated signal, and forming a curved surface with a first array of discrete elements. The exemplary method may further include impinging the initiated signal upon the curved surface, thereby applying a correction to the initiated signal determined at least in part by the curved surface. | 11-15-2012 |
20120301157 | CHROMATIC DISPERSION COMPENSATION USING SIGN OPERATIONS AND LOOKUP TABLES - Methods and devices for compensating for chromatic dispersion are shown that include receiving an input data signal, applying a filter to the data signal, and outputting a CD compensated signal. Applying the filter includes convolving known filter coefficients with a plurality of delayed versions of the data signal using addition and at least one inverse sign operation or using lookup tables and combining outputs to produce a CD compensated signal. | 11-29-2012 |
20130077979 | NONLINEAR COMPENSATING APPARATUS AND METHOD AND TRANSMITTER - The present invention provides a nonlinear compensating apparatus and method and a transmitter. The nonlinear compensating apparatus includes: an information sequence acquiring unit, configured to acquire a symbol information sequence of the pulse signal; a perturbation quantity acquiring unit, configured to calculate the weighted sum of interaction items of pulses on one or more moments relative to the current moment, to obtain the perturbation quantity produced on a transmission link with a certain length, and rotate the obtained perturbation quantity by a predetermined phase; and an information compensating unit, configured to calculate the difference between the symbol information sequence and the perturbation quantity to obtain a compensated symbol information sequence. With the embodiments of the present invention, the performance of the system, especially the performance of NRZ (Not Return to Zero) code, may be further improved. | 03-28-2013 |
20130216237 | SIGNAL TRANSMISSION DEVICE - A signal transmission device drives a light-emitting element and outputs an optical signal depending on a data signal from an electronic device. The device includes an element driving portion which supplies a driving current to the light-emitting element, wherein the driving current is obtained by superimposing a modulation current on a bias current, the modulation current being dependent on the data signal indicating emitting information of the light-emitting element. A temperature compensation portion of the device controls the bias current and the modulation current depending on the temperature so that a temperature-current characteristic of the light-emitting element is reproduced based on the voltage which is dependent on the temperature and the voltage which is independent from the temperature, thereby performing current control depending on the temperature. | 08-22-2013 |
20130243442 | OPTICAL TRANSMISSION APPARATUS AND CHARACTERISTIC COMPENSATION METHOD - A characteristic compensation method includes obtaining compensation information when degradation of a transmission characteristic of an optical transmission path of a received light signal is compensated for by using digital signal processing with respect to an electric signal obtained by photoelectrically converting the light signal, calculating an compensation value for a characteristic compensation device that optically compensates for degradation of the transmission characteristic to start characteristic compensation, based on the compensation information with respect to the light signal, setting the compensation value in the characteristic compensation device, and switching a state in which compensation is done using the digital signal processing to a state in which compensation is done using the characteristic compensation device after the setting of the compensation value is completed. | 09-19-2013 |
20130302038 | ELECTRONIC DISPERSION CORRECTION CIRCUIT FOR OPTICAL TRANSMISSION SYSTEM - A dispersion correction circuit is provided for use with an input driving signal. The dispersion correction circuit includes an input portion, an output portion and a filter portion. The input portion is arranged to receive the input driving signal. The output portion can output an output signal based on the input driving signal. The filter portion is disposed between the input portion and the output portion. The filter portion includes a varactor, a DC bias portion, and a transformer. The DC bias portion provides a DC bias to the varactor. | 11-14-2013 |
20130302039 | ELECTRONIC DISPERSION CORRECTION CIRCUIT FOR OPTICAL TRANSMISSION SYSTEM - A dispersion correction circuit is provided for use with an input driving signal. The dispersion correction circuit includes an input portion an output portion and a filter portion. The input portion is arranged to receive the input driving signal. The output portion can output an output signal based on the input driving signal. The filter portion is disposed between the input portion and the output portion. The filter portion includes a first varactor, a DC bias portion, and a second varactor. The DC bias portion provides a DC bias to the first varactor. The first varactor is arranged in a first polarity direction, and the second varactor is arranged in a second polarity direction that is the same as the first direction. | 11-14-2013 |
20140029957 | FREQUENCY EQUALIZATION FOR AN OPTICAL TRANSMITTER - An optical transmitter configured to perform digital signal equalization directed at mitigating the detrimental effects of a frequency roll-off in the transmitter's optical I-Q modulator. In various embodiments, a frequency-dependent spectral-correction function used for the digital signal equalization can be constructed to cause the spectrum of the modulated optical signal generated by the transmitter to have a desired degree of flatness in the vicinity of an optical carrier frequency and/or to at least partially mirror the frequency roll-off in the optical I-Q modulator. | 01-30-2014 |
20140140708 | EMPHASIS SIGNAL GENERATING CIRCUIT - An emphasis signal generating circuit includes: a branch circuit configured to split a signal into a plurality of paths; a delay circuit provided in one or more of the paths into which the signal has been split by the branch circuit, the delay circuit being configured to delay one or more signals; a phase compensation circuit provided in one or more of the paths into which the signal has been split by the branch circuit, the phase compensation circuit having such characteristics that a transmission intensity of a signal is low in a low frequency band and is high in a high frequency band; and an addition/subtraction circuit configured to perform addition and/or subtraction of signals from the plurality of paths and output a result. | 05-22-2014 |
20140301742 | Method for Improving Signal Quality of a Digital Signal Being Transmitted Through a Non-Linear Device and Apparatus Using the Same - A digital signal processing method has steps of pre-emphasizing a digital signal, and then processing the pre-emphasized digital signal through a non-linear device. In the pre-emphasizing step, an undershoot is applied to a first level of the digital signal at a positive signal transition or an overshoot is applied to the digital signal at a negative first signal transition. | 10-09-2014 |
20140369700 | TUNABLE LASER EMISSION DEVICE - A wavelength tunable laser emission device ( | 12-18-2014 |
20160127047 | METHOD, DEVICE AND COMMUNICATION SYSTEM FOR REDUCING OPTICAL TRANSMISSION IMPAIRMENTS - A method and device is provided for reducing optical transmission impairments, particularly nonlinear effects, of at least one link Said method comprising the following steps: extracting a phase information (Δθ) from an optical signal ( | 05-05-2016 |