Class / Patent application number | Description | Number of patent applications / Date published |
398195000 | Including feedback | 27 |
20090310978 | COMPLEMENTARY OPTICAL WIRING SYSTEM - A complementary optical wiring system has a transmitting circuit configured to combine a delayed signal obtained by delaying a digital electric input signal by a time shorter than a minimum pulse width of the digital electric input signal with the digital electric input signal to generate a first electric pulse signal synchronized with a rising edge of the digital electric input signal and a second electric pulse signal synchronized with a falling edge of the digital electric input signal, a first light-emitting element configured to convert the first electric pulse signal to a first optical signal, a second light-emitting element configured to convert the second electric pulse signal to a second optical signal, a first optical transmission path configured to transmit the first optical signal, a second optical transmission path configured to transmit the second optical signal, a first light-receiving element configured to convert the first optical signal transmitted through the first optical transmission path to a third electric pulse signal, a second light-receiving element configured to convert the second optical signal transmitted through the second optical transmission path to a fourth electric pulse signal and a receiving circuit configured to generate a digital electric output signal corresponding to the digital electric input signal in synchronization with the third and fourth electric pulse signals. | 12-17-2009 |
20100215379 | AUTO-POWER CONTROL CIRCUIT TO MAINTAIN EXTINCTION RATIO OF OPTICAL OUTPUT FROM LASER DIODE - The present invention provides an auto-power control (APC) circuit and a method to stabilize the extinction ratio of an optical output from a laser diode (LD) in an optical transmitter. The APC circuit according to the invention includes two feedback loops for the modulation I | 08-26-2010 |
20100254717 | APPARATUS AND METHOD FOR CONTROLLING THE OPTICAL OUTPUT POWER OF A LASER IN AN OPTICAL TRANSMITTER (TX) - A semi-open feedback loop optical output power control apparatus and method are provided for use in an optical TX. The apparatus and method enable input data signals having content frequencies that are below the cutoff frequency of the optical output power monitoring and control feedback loop to be utilized. This is accomplished at least in part by opening and closing (i.e., is disabling and enabling) the feedback loop based on whether or not one or more transitions in the input data signal to the optical TX from a logic 0 to a logic 1, or vice versa, are detected within a predetermined timing interval. In addition, the apparatus and method provide these and other advantages without causing the optical TX to have an increased link startup settling time period. The feedback loop has a low pass filter (LPF) that has a selectable bandwidth. The bandwidth of the LPF is set to a high bandwidth at startup to enable shorter link startup settling time periods to be achieved by the TX and is set to a low bandwidth at a later time to enable the feedback loop to cause more accurate adjustments to the optical output power of the laser to achieve a better bit error rate (BER). | 10-07-2010 |
20100303472 | APPARATUS AND METHOD FOR ADAPTIVELY CONTROLLING THE IMPULSE RESPONSE OF THE OPTICAL SIGNAL OUTPUT FROM A LASER OF AN OPTICAL TRANSMITTER (TX) - An apparatus and a method are provided for adaptively adjusting the impulse response of the optical output of the laser of the optical TX in a way that ensures that the optical waveform being transmitted from the optical TX into the optical waveguide of the optical link has a desired waveform shape that improves or optimizes the performance of the optical link across variations in temperature, power supply, laser process corners, IC process corners, component aging, mechanical manufacturing tolerances, and part alignment tolerances. Adaptively adjusting the impulse response of the optical signal output from the laser in this way allows the optical TX to dynamically adapt to and compensate for a wide range of factors that typically cause performance degradation and result in reduced product yields, increased testing times, and increased test complexity, and higher costs. This, in turn, allows manufacturing tolerances and alignment tolerances to be relaxed, test times and test complexity to be reduced, and overall manufacturing and testing costs to be reduced. | 12-02-2010 |
20110058821 | OPTICAL TRANSMISSION APPARATUS, OPTICAL TRANSMISSION SYSTEM, AND OPTICAL TRANSMISSION METHOD - An optical transmission apparatus in an optical transmission system that transmits an optical signal through a transmission fiber includes a measurement device that measures Raman gain efficiency of the transmission fiber; a level determiner that determines an input level of the optical signal based on Raman gain efficiency measured by the measurement device; and a controller that controls a level of the optical signal input to the transmission fiber to become the input level determined by the level determiner. | 03-10-2011 |
20110158655 | Dispersion Measurement of Optical Fibres During Operation - The invention at hand concerns a method and a system for transmitting data in an optical transmission system. A measuring signal is generated having a wavelength which differs from the wavelengths of a data signal that includes the data to be transmitted. The measuring signal is coupled in the optical transmission system, reflected after passing through the transmission path and decoupled again. The coupled measuring signal is compared with the decoupled reflected measuring signal. By taking into account the comparison results, a compensation of the change of the data signal resulting from the dispersion in the fiber is performed in such a way that the data included in the data signal can be used. | 06-30-2011 |
20110229150 | OPTICAL MODULATION APPARATUS AND OPTICAL MODULATION METHOD - An optical modulation apparatus includes a first modulator, a second modulator, a multiplexer, a calculator and an adjustor. The first modulator configured to modulate light emitted by a light source using a first input signal and output a first modulated signal. The second modulator configured to modulate the light using a second input signal and output a second modulated signal. The multiplexer configured to multiplex the first and second modulated signals and output a multiplexed signal. The calculator configured to calculate a power difference between a higher-side frequency component having a frequency higher than a center frequency of the multiplexed signal and a lower-side frequency component having a frequency lower than the center frequency. The adjustor configured to adjust delays of the first and second input signals based on the power. | 09-22-2011 |
20110229151 | PHOTOELECTRIC ENCODER - A photoelectric encoder includes a scale; a detector; alight application section; a pair of origin signal reception sections; and a signal processing section adapted to provide the maximum value of the signal level output from the origin signal reception sections by side lobe light occurring as reflected on the origin mark as a stipulated value, provide an effective area of origin detection between the first position at which output of one of the origin signal reception sections for outputting a larger signal level than the stipulated value earlier than the relative displacement becomes a larger signal level than the stipulated value and the first position at which output of the other origin signal reception section exceeds the stipulated value and then becomes a smaller signal level than the stipulated value, and configured to generate the origin detection signal in the effective area. | 09-22-2011 |
398196000 | For wavelength control | 1 |
20120082469 | AUTOMATIC WAVELENGTH CONFIGURATION - An optical transmitter may include a tunable signal source configured to emit a signal to an optical fiber system; a back scatter detector for measuring an amount of back scatter observed following injection of the signal to the optical fiber system; and control logic. The control logic may be configured to cause the tunable signal source to scan through a range of wavelengths. Measured amounts of back scatter are received for each of the wavelengths. A wavelength corresponding to a peak back scatter amount may be identified and the tunable signal source may be set based on the identified wavelength. | 04-05-2012 |
398197000 | For power control | 7 |
20090003843 | Optical transmitter and method for control the same - An optical transmitter that reduces the stimulated Brillion scattering occurred within a transmission optical fiber and a method to control the optical transmitter are disclosed. The optical transmitter with a type of the chirp managed laser diode (CML) comprises a laser diode modulated with a high frequency signal and biased with a relatively large bias current and an optical filter. When the modulation signal is stopped, an optical signal with relatively large power and narrow spectrum may enter the transmission fiber, which causes the stimulated Brillouin scattering. In the present optical transmitter, when the modulation signal is absent, an auxiliary signal is superposed on the bias current. | 01-01-2009 |
20090060529 | Optical bench fiber optic transmitter - The subassembly includes a laser for emitting signals towards fibers to be monitored, a passive alignment carrier, a photodetector for monitoring reflected laser signals from the fibers and for monitoring laser output power, and an optical fiber. The laser is disposed within the passive alignment carrier. The optical fiber is embedded in the passive alignment carrier, and has an angled fiber facet. The laser emits signals toward and through the angled fiber facet, whereby a portion of the laser signal illuminates the photodetector, and another portion illuminates the fibers that are being monitored and reflects back to the photodetector such that faults on the fibers can be detected. | 03-05-2009 |
20090274471 | METHOD AND APPARATUS FOR CONTROLLING THE OPTICAL OUTPUT POWER FROM A BURST MODE LASER - An optical network terminal is provided for use in a passive optical network (PON). The optical network terminal includes a data port for receiving data packets from an external device and a processor for converting the data packets to data link frames. In addition, the optical network terminal includes a memory configured to store a time division multiplexing scheme identifying a time slot assigned to each of a plurality of network nodes in the PON for transmission of upstream optical signals. An optical transceiver is provided for converting the data link frames to upstream optical signals and transmitting the optical signals on an upstream TDMA (time division, multiple access) channel to an Optical Line Terminal (OLT). The optical transceiver includes a burst mode laser diode for generating the optical signals and a burst mode laser driver for biasing the laser diode with a bias signal and a modulation bias signal. The laser driver includes a dual closed loop feedback control circuit. The dual closed loop feedback control circuit is configured to measure and adjust a logic zero output power level from the laser diode during a time slot identified from the time division multiplexing scheme stored in the memory. | 11-05-2009 |
20100046963 | OPTICAL REGENERATING APPARATUS AND OPTICAL REGENERATING METHOD - An optical regenerating apparatus includes a photoreceiver unit that receives an optical signal and converts the optical signal into an electrical signal; a reproducing unit that identifies a code of the electrical signal by comparing the electrical signal with a threshold, and reproduces and outputs the identified code; a threshold adjusting unit that calculates a threshold that is lower than the central value of the amplitude of the electrical signal and according to the calculated threshold, adjusts the threshold at the reproducing unit; and a control unit that, based on a variation in the power of the electrical signal, controls the adjustment of the threshold by the threshold adjusting unit. | 02-25-2010 |
20110038641 | OPTICAL TRANSCEIVER WITH GRADUAL STOP OR START FUNCTION - The present invention provides an optical transmitter applicable to the WDM communication system. The optical transmitter includes a light-emitting device, an APC circuit and a processing unit. The processing unit, responding to a command TX_DISABL, which is sent from the control unit that communicates with the host controller, stops the optical output power of the transmitter by decreasing the reference to a preset value in step wise. Moreover, the processing unit, responding to a command ENABLE that is also sent from the control unit, starts the optical output by increasing the reference to another preset value in step wise. | 02-17-2011 |
20140186056 | Closed Loop Optical Modulation Amplitude Control - Systems and methods are provided for a low frequency AC comparison circuit. The low frequency AC comparison circuit includes circuitry configured to receive a monitoring signal generated by an optical detector, the monitoring signal being proportional to an amount of light generated by an optical transmission device that transmits based on a data signal that is received by an optical driver. The comparison circuit is further configured to generate a modulation current control signal that is transmitted to the optical driver based on a comparison of a low frequency AC component of the monitoring signal and a correlated low frequency AC component of the data signal. | 07-03-2014 |
20160254866 | METHOD AND APPARATUS FOR CONTROLLING, MONITORING, AND COMMUNICATING WITH TUNABLE OPTICAL DEVICES AND SUBASSEMBLIES | 09-01-2016 |
398198000 | For modulator control | 11 |
20080219678 | CONTROL SYSTEM AND CONTROL METHOD FOR CONTROLLING OPTICAL MODULATOR - A control system for controlling an optical modulator that intensity-modulates input light, the system includes an automatic bias control circuit configured to control an operating point of an optical modulator due to a bias voltage, including (i) a low-frequency signal superimposing unit configured to superimpose a low-frequency signal having a frequency lower than the frequency of a data signal on the data signal; (ii) a photoelectric converter configured to convert an optical signal intensity-modulated with an optical modulator into a voltage signal based on the data signal on which the low-frequency signal is superimposed; (iii) an error voltage detector configured to detect an error voltage corresponding to the low-frequency signal superimposed on the data signal from the voltage signal; and (iv) a bias controller configured to control a bias voltage for applying to the optical modulator based on the error voltage, and an automatic bias control stabilizing circuit configured to stabilize the automatic bias control circuit to control the operating point of the optical modulator based on a direct current voltage extracted from the voltage signal. | 09-11-2008 |
20090034988 | Control apparatus and control method for optical modulator - An object of the invention is to provide a control system in which the phase shift between drive signals of an optical modulator can be reliably detected and compensated by a simple configuration. To this end, a control apparatus of the invention, for an optical modulator generating a signal light of a CS-RZ modulation system or the like by two LN modulators connected in series, detects the phase shift between drive signals given to the former and latter stage LN modulators, or judges the phase shift between the drive signals based on intensity information of the electric spectrum of the signal light output from the optical modulator, to control the phases of the drive signals so as to minimize the phase shift. As a result, the phase shift between the drive signals can be reliably detected and compensated by an electric circuit with a simple configuration. | 02-05-2009 |
20090041475 | MODULATOR DRIVER CIRCUIT WITH SELECTABLE ON-CHIP TERMINATION - A method and apparatus to accommodate differing output loads without sacrificing impedance matching in an optical modulator driver. | 02-12-2009 |
20090297168 | OPTICAL COMMUNICATION APPARATUS AND OPTICAL ADD/DROP APPARATUS - An apparatus comprising an optical modulator modulating a light in accordance with a modulation signal and an operating point of the optical modulator, to thereby output a modulated optical signal; and a controller controlling the operating point in accordance with a branched portion of the modulated optical signal and a detected intensity of the modulation signal so that the operating point is kept stable when the detected intensity falls below a predetermined value. | 12-03-2009 |
20090324255 | Light transmitting apparatus and method for controlling the same - A light transmitting apparatus of the invention includes: a light transmitting section having a light source and an EA modulator, and a control section that controls the optical output power of the light transmitting section to be constant, based on a monitor value of EA photoelectric current. The control section uses a reference value corresponding to a wavelength of the light source, from amongst reference values of the EA photoelectric current that are different for each wavelength, and feedback controls the light transmitting section depending on a difference between the reference value and the monitor value. As a result it is possible to reliably suppress fluctuations in the optical output power due to changes in the wavelength of the light source. | 12-31-2009 |
20100008680 | Optical modulating device with frequency multiplying technique for electrical signals - The present invention relates to an optical modulating device with frequency multiplying technique for electrical signals, which primary comprises a mixer, which generates a mixed data signal from a first electrical signal and a second electrical signal. The mixed data signal is then received by a first phase shift device to have its phase shifted and becomes a first shifted signal. The first electrical signal is further received by a second phase shift device to have its phase shifted and becomes a second shifted signal. The present invention further comprises an integrated electro-optic modulator (Mach-Zehnder modulator), which is used to receive an input optical signal, the mixed data signal, the first shifted signal, the second shifted signal and the first electrical signal mentioned above, the integrated electro-optic modulator will then modulates the input optical signal into a frequency multiplying output optical signal that carries the first electrical signal and the second electrical signal. The present invention can carry and transmit amplitude shift keying signals and vector modulation signals, thereby provides a more advanced optical communication transmission service. | 01-14-2010 |
20100054757 | BIAS CONTROLLER FOR AN OPTICAL MODULATOR - A bias controller for an optical modulator. The modulator includes a bias electrode that is operable when appropriately biased by an applied bias voltage to configure the modulator to operate at quadrature, and the bias controller includes: a generating arrangement for generating power signals indicative of the optical output power of the modulator; and a processor operably connected to the generating arrangement and said bias electrode and arranged to receive said power signals from said generating arrangement and to control the bias voltage applied to said bias electrode. The processor is configured to vary the bias voltage applied to said bias electrode and to determine from power signals received from said generating arrangement a peak optical output power for said modulator, and to determine in dependence upon said peak optical power a target optical power for quadrature with reference to a store of predetermined values for peak output power and respective corresponding values of target optical power for quadrature. Other embodiments relate to a multi-channel bias controller, and to a method for controlling voltage bias in a modulator. | 03-04-2010 |
20100119239 | BIAS CONTROL APPARATUS AND METHOD FOR OPTICAL MODULATOR - Examples of apparatus and methods are provided for controlling a bias in an optical modulator. An exemplary apparatus may comprise an optical modulator operable to modulate an optical signal. The optical modulation apparatus may comprise a photodetector disposed to receive at least a portion of the modulated optical signal. The optical modulation apparatus may comprise a bias controller coupled to both the optical modulator and the photodetector. The bias controller may be configured to receive a dither signal and to produce a bias feedback signal for the optical modulator. The bias feedback signal may be based on a ratio between an odd order harmonic signal of the modulated optical signal and an even order harmonic signal of the modulated optical signal. | 05-13-2010 |
20140056597 | System and Method for Broadband Transmissions on a Fiber Optic with Suppression of Second and Third Order Distortions - A system and method for transmitting telecommunication signals through a fiber optic, with suppression of second and third order distortions, requires a signal processor for generating a sub-octave broadband signal. An Electro-Absorption Modulator (EAM) is provided to modulate the sub-octave broadband signal into an optical signal λ. And, a DC offset voltage is used to alter optical output power in the optical signal λ. The sub-octave broadband transmission then minimizes second order distortions of the optical signal λ, and the DC offset minimizes third order distortions when the optical signal λ is transmitted on the fiber optic. | 02-27-2014 |
20180026723 | Inherently Broadband Linearized Electro-Optic Modulator with Customizable Performance | 01-25-2018 |
20220140912 | PHASE RESPONSE MEASUREMENT METHOD AND APPARATUS - An apparatus at least includes a processor to, after a first signal passes through a narrowband photodetector, perform frequency mix of the first signal with a first reference signal and a second reference signal respectively and perform noise reduction, to obtain a first detection signal and a second detection signal. The first signal is obtained after a measurement signal passes through a filtering module of an optical transmitting end, the measurement signal being transmitted in a path of multiple branches, signals not transmitted in other paths of the multiple branches, a frame structure of the measurement signal including at least one two-tone signal, two tones in the two-tone signal having a fixed tone interval. The processor is to calculate group delays at multiple frequency bins according to the first detection signal and the second detection signal; and determine a phase response of the filtering module of the optical transmitting end in the path according to the group delays at multiple frequency bins. | 05-05-2022 |