| Class / Patent application number | Description | Number of patent applications / Date published |
|---|
| 359337100 | Spectral gain flattening or equalization | 37 |
| 20080231944 | OPTICAL EQUALIZATION OF MULTI-LEVEL SYMBOL CONSTELLATIONS - A method of optically equalizing a multi-level (amplitude or phase) optical signal through the effect of an optical equalizer wherein the optical equalizer (OEQ) is placed at either a transmission end or a receiver end of the optical communications link and a tap delay characteristic of the OEQ need not be determined by symbol spacing, rather it may advantageously be adjusted to desirably compensate non-linear mapping performed in the modulation process or simultaneous operation on a plurality of wavelength division multiplexed (WDM) channels. | 09-25-2008 |
| 20080239470 | INDIVIDUAL BAND GAIN EQUALIZER FOR OPTICAL AMPLIFIERS - A control apparatus comprises a light monitoring unit for dividing a signal wavelength band into at least a band in which output light power of an optical amplifier tends to decrease at an decrease in the number of signal wavelengths and a band including a gain deviation band, and for monitoring inputted light power for the individual divided bands, a calculation unit for obtaining the number of signal wavelengths in the individual divided bands based on a monitor result, and a target gain correction unit for correcting a target gain based on a result of the calculation. This suppresses a transient variation of signal light level due to SHB or SRS at a high speed with a simple configuration without deteriorating noise characteristic, thus enabling optical amplifiers to be further disposed in a multi-stage fashion, which can lengthen the transmission distance of a transmission system including an optical add/drop unit. | 10-02-2008 |
| 20080316591 | Optical amplifier - According to an aspect of the embodiment of the invention, an optical amplifier including an input port, an output port, a plurality of amplifying parts, an optical attenuator, a gain controller and an optical attenuator controller. The plurality of amplifying parts includes an optical amplification medium and a pumping light source for generating pump light. The optical attenuator is optically connected between the amplifying parts. The gain controller controls the pump light power of the pump sources, respectively, in such a way that the ratio decreases in accordance with the gain set value increasing and the ratio interpose between a first threshold level and a second threshold level. The optical attenuator controller controls attenuation of the optical attenuator in order to maintain the sum of generating gains of the amplifying parts in the gain set value in accordance with a state of the signal light inputted into the input port. | 12-25-2008 |
| 20090002808 | Nonlinear Chirped Pulse Fiber Amplifier With Pulse Compression - A chirped-pulse fiber amplification method and system operates with large nonlinear phase shifts (as large as ˜20π or more). In this regime, the pulse spectrum is modified by strong self-phase modulation and gain shaping. With large-enough nonlinear phase shift, substantial spectral broadening occurs. The amplified spectrum can therefore be much broader than the spectrum that is obtained with small nonlinear phase shifts. The broader spectrum enables the formation of a shorter pulse, and the bandwidth generated in nonlinear chirped-pulse amplification can in fact be exploited to generate shorter pulses. Ultimately, this allows the generation of pulses shorter than the gain-narrowing limit of a fiber amplifier. | 01-01-2009 |
| 20090052015 | METHOD FOR ACQUIRING SPECTRUM SHAPE OF A GAIN FLATTENING FILTER IN AN OPTICAL AMPLIFIER - A method for acquiring spectrum shape of a gain flattening filter of a doped optical fiber amplifier comprises the steps of: measuring spectrum shapes at two gain point (H, L) of the doped optical fiber with invariable fiber length respectively; and acquiring various gain spectrums of the doped optical fiber with various fiber length and various population inversion level according to an expression: | 02-26-2009 |
| 20090086310 | CONTROLLER WHICH CONTROLS A VARIABLE OPTICAL ATTENUATOR TO CONTROL THE POWER LEVEL OF A WAVELENGTH-MULTIPLEXED OPTICAL SIGNAL WHEN THE NUMBER OF CHANNELS ARE VARIED - An optical amplifying apparatus which includes an optical amplifier, an optical attenuator and a controller. The optical amplifier amplifies a light signal having a variable number of channels. The optical attenuator passes the amplified light signal and has a variable light transmissivity. Prior to varying the number of channels in the light signal, the controller varies the light transmissivity of the optical attenuator so that a power level of the amplified light signal is maintained at an approximately constant level that depends on the number of channels in the light signal prior to the varying the number of channels. While the number of channels in the light signal is being varied, the controller maintains the light transmissivity of the optical attenuator to be constant. Subsequent to varying the number of channels in the light signal, the controller varies the light transmissivity of the optical attenuator so that a power level of the amplified light signal is maintained at an approximately constant level that depends on the number of channels in the light signal subsequent to the varying the number of channels. | 04-02-2009 |
| 20100046065 | TUNABLE OPTICAL FILTER - Consistent with the present disclosure a compact, integrated tunable filter is provided that can adjust the power levels of optical signals output from an optical amplifier, for example, so that the amplifier has a uniform spectral gain. The tunable optical filter includes a planar lightwave circuit (PLC) having cascaded Mach-Zehnder interferometers, each of which having corresponding differential optical delays. At least one of the differential optical delays is different than the rest. Alternatively, the differential optical delays are different from one another. Each of the Mach-Zehnder interferometers is connected to one another by a tunable optical coupler. Such a filter has an improved frequency response in that the number of shapes that the transmission spectrum may have is increased. Accordingly, the optical filter may be more finely tuned to more effectively flatten, for example, the output of the optical amplifier. In addition, since the tunable optical filter is realized with a planar lightwave circuit (PLC) component, manufacturing costs can be reduced, and a more compact device can be obtained. | 02-25-2010 |
| 20100195192 | Optical Signal Amplifier, Method of Optical Amplification and Optical Network - An optical signal amplifier for use in optical networks operating in a ring configuration comprising a first doped optical fibre loop pumped by a first laser and a second optical fibre loop pumped by a second laser. | 08-05-2010 |
| 20100284062 | WAVELENGTH DETERMINING APPARATUS, METHOD AND PROGRAM FOR THIN FILM THICKNESS MONITORING LIGHT - A multi-layer optical thin film filter comprising plural deposited optical thin films, wherein optical thin film thickness for each of said optical thin films has a predetermined wavelength spectrum in a predetermined gain equalization band and a predetermined wavelength spectrum in a pumping light transmission band other than said gain equalization band. | 11-11-2010 |
| 20110063720 | Optical amplifiers using switched filter devices - Described are Gain Flattening Filters (GFFs) implemented using mechanical translating assemblies to move selected thin film Gain Attenuating Filters (GAFs), and combinations of selected GAFs, into or out of the output path from an optical amplifier. The GAFs may be used singly, or in combinations that synthesize many target filter characteristics. The GFF is primarily adapted for WDM systems operating with a wavelength range of approximately 1520 nm to 1620 nm. Several embodiments are shown for effectively combining different GAFs to provide multiple GFF curves. | 03-17-2011 |
| 20110116159 | ARTICLE COMPRISING A WIDEBAND OPTICAL AMPLIFIER WITH A WIDE DYNAMIC RANGE - A multi-channel optical amplifier arrangement operating over a particular bandwidth is provided. The amplifier arrangement includes at least one optical amplifier stage that includes a rare-earth doped optical waveguide, at least one pump source for supplying optical pump energy to the doped optical waveguide, and at least one coupler for coupling the optical pump energy to the doped optical waveguide. The amplifier arrangement also includes a dynamic range enhancer (DRE) having an input and an output and a plurality of distinct optical paths each selectively coupling the input to the output. At least two of the optical paths produce different gain spectra across the particular operating bandwidth. The DRE further includes an optical path selector for selecting any optical path from among the plurality of optical paths such that for all channels in the particular bandwidth the selected path optically couples the input to the output of the DRE. An input or output of the optical amplifier stage is optically coupled to the output or the input, respectively, of the DRE. | 05-19-2011 |
| 20110194173 | METHOD AND DEVICE FOR SPECTRAL CONTROL IN FREQUENCY CONVERSION LASER AMPLIFIERS - The invention relates to a method of spectral control in a frequency-shift laser chain for producing ultra-short pulses and comprising at least two laser-crystal amplifier stages, for cooling the crystal of one of the amplifier stages of the chain. | 08-11-2011 |
| 20110205620 | CONTROLLER WHICH CONTROLS A VARIABLE OPTICAL ATTENUATOR TO CONTROL THE POWER LEVEL OF A WAVELENGTH-MULTIPLEXED OPTICAL SIGNAL WHEN THE NUMBER OF CHANNELS ARE VARIED - An optical amplifying apparatus which includes an optical amplifier, an optical attenuator and a controller. The optical amplifier amplifies a light signal having a variable number of channels. The optical attenuator passes the amplified light signal and has a variable light transmissivity. Prior to varying the number of channels in the light signal, the controller varies the light transmissivity of the optical attenuator so that a power level of the amplified light signal is maintained at an approximately constant level that depends on the number of channels in the light signal prior to the varying the number of channels. While the number of channels in the light signal is being varied, the controller maintains the light transmissivity of the optical attenuator to be constant. Subsequent to varying the number of channels in the light signal, the controller varies the light transmissivity of the optical attenuator so that a power level of the amplified light signal is maintained at an approximately constant level that depends on the number of channels in the light signal subsequent to the varying the number of channels. | 08-25-2011 |
| 20110228381 | OPTICAL AMPLIFYING DEVICE, GAIN CONTROL METHOD, OPTICAL TRANSMISSION DEVICE, AND GAIN CONTROL DEVICE - An apparatus includes: an optical amplifier configured to perform optical amplification for gain by controlling so as to be a target gain; a correction power calculator configured to calculate, in response to amplified spontaneous emission light input to the optical amplifier, correction power corresponding to an amount of gain depression in a bandwidth in which spectral hole-burning occurs in the optical amplifier; and a gain controller configured to calculate, using the correction power calculated in the correction power calculator, a gain for controlling the optical amplification performed in the optical amplifier and perform, using the calculated gain, a control operation so that the gain of the optical amplification becomes the target gain. | 09-22-2011 |
| 20110299153 | ARTICLE COMPRISING A MULTICHANNEL OPTICAL AMPLIFIED TRANSMISSION SYSTEM WITH FUNCTIONAL UPGRADE CAPABILITIES AND UNIVERSAL MODULES - A universal inline functional module for operation with nonzero average gain G≠0 dB over a bandwidth is provided. The module includes at least one optical functional element producing loss over the bandwidth and at least one rare-earth doped fiber segment. The module produces a flat gain spectrum to within a specified tolerance when made to operate at an average gain of 0 dB over the bandwidth. | 12-08-2011 |
| 20120188631 | OPTICAL AMPLIFICATION APPARATUS - In an optical amplification apparatus an optical amplifier amplifies an optical signal at set gain. An equalizer changes loss of the amplified optical signal according to wavelengths. A processor controls the equalizer so as to make the equalizer have a loss-wavelength characteristic corresponding to a gain tilt of the optical amplifier which occurs according to the set gain. | 07-26-2012 |
| 20140029082 | OPTICAL AMPLIFIER AND METHOD - An optical amplifier includes: a rare-earth doped fiber configured to amplify signal light to thereby produce a amplified signal light; a gain control circuit configured to control an optical gain of the rare-earth doped fiber; a photodetector configured to detect intensities of different wavelength of light obtained from the amplified signal light; and an abnormality detection circuit configured to detect an abnormality of the signal light in accordance with a ratio or a difference between the intensities of the different wavelength. | 01-30-2014 |
| 20140063592 | 6x28-Gbaud Few-Mode Fiber Recirculating Loop Transmission with Gain-Equalized Inline Few-Mode Fiber Amplifier - Disclosed herein are methods, structures and systems for few-mode fiber (FMF) transmission including an optical amplifier exhibiting modal gain control suitable for such transmission in which higher order modes are amplified. An exemplary evaluation system is described and results presented. | 03-06-2014 |
| 20140185131 | Multi-Wavelength Light Source Apparatus - The present invention discloses a multi-wavelength light source apparatus. The multi-wavelength light source apparatus includes: a pump light source, configured to provide pump light; an erbium-doped optical fiber, configured to absorb energy of the pump light and emit wide-spectrum laser light; and an optical fiber, configured to filter the wide-spectrum laser light and output a multi-wavelength optical signal in a free spectral range of the optical filter, where the multi-wavelength optical signal is incident on the erbium-doped optical fiber, and the erbium-doped optical fiber is further configured to re-amplify and output the incident multi-wavelength optical signal. In the multi-wavelength light source apparatus in the embodiments of the present invention, a wavelength of output light can be selected, spectral energy of the output light is concentrated, and power of the output light is high. | 07-03-2014 |
| 20150062692 | REDUCING THERMAL DEPENDENCE OF AMPLIFIER GAIN - Devices and methods for lessening a thermal dependence of gain profile of an optical amplifier are disclosed. An optical beam is split in two sub-beams with a thermally variable power splitting ratio. One sub-beam travels a longer optical path length than the other. When the two sub-beams are recombined, they interfere with each other, causing the throughput to be wavelength dependent. An amplitude of this wavelength dependence is thermally variable due to the thermally variable power splitting ratio. The thermally variable power splitting ratio and the optical path length difference are selected so as to offset a thermal variation of a spectral gain profile of an optical amplifier. | 03-05-2015 |
| 20150325972 | SYSTEM AND METHOD FOR THE OPTICAL AMPLIFICATION OF ULTRASHORT LIGHT PULSES BEYOND THE LIMIT OF THE SPECTRAL GAIN BAND - A system for the optical amplification of high-energy ultrashort light pulses, includes: an oscillator that can emit light pulses of sub-picosecond duration τ | 11-12-2015 |
| 359337110 | Feedback | 16 |
| 20090303576 | TRANSIENT OPTICAL POWER SUPPRESSING APPARATUS, METHOD, AND NETWORK - An apparatus for suppressing optical power transients includes a variable optical attenuator receiving an input optical signal and outputting an output optical signal; an optical power sensing element coupled to the input optical signal and sensing a portion of the input optical signal; and a feedforward loop controller coupled to the variable optical attenuator and to the optical power sensing element; the feedforward control loop providing feedforward control of the variable optical attenuator to reduce optical power transients of the input optical signal and maintain a substantially constant output power based on the input optical power and a reference value; the variable optical attenuator having a default opaque state in which the input optical signal is substantially attenuated when power is not being supplied to said variable optical attenuator. Variations include feedback loop controllers and a combination feedback and feedforward loop controllers. | 12-10-2009 |
| 20100118387 | OPTICAL AMPLIFIER - An optical amplifier apparatus for amplifying a wavelength division signal light includes a detector for detecting an inputted wavelength division signal light, a dispersion compensator for compensating for a dispersion of the inputted wavelength division signal light, an optical amplifier for amplifying the inputted wavelength division signal light after compensation by stimulated emission of an optical gain medium including a rare-earth element, a propagation delay detector for detecting a propagation delay time of the wavelength division signal light between the detector and the optical amplifier, and a controller for controlling the gain of the optical amplifier on the basis of the propagation delay time such that the change of the gain of the optical amplifier is adjusted by the propagation delay time. | 05-13-2010 |
| 20100123949 | OPTICAL AMPLIFYING DEVICE - An optical amplifying device includes a first optical amplifier for amplifying signal light; a second optical amplifier serially connected with the first optical amplifier; an optical device for compensating deterioration of the signal light, the optical device arranged between the first optical amplifier and the second optical amplifier; a variable optical attenuator for attenuating the signal light, the variable optical attenuator arranged between the first optical amplifier and the second optical amplifier; a first automatic level controller for detecting a second amplifier output power and for controlling driving status of the second amplifier in a predetermined output power level; and a first automatic gain controller for detecting an input power of the second optical amplifier and an output power of the second optical amplifier, and for controlling an optical attenuation value of the variable optical attenuator. | 05-20-2010 |
| 20120212800 | OPTICAL RECEIVING APPARATUS AND OPTICAL AMPLIFYING APPARATUS - An optical receiving apparatus includes an optical amplification medium that receives an excitation light and an input light, an optical loss medium that receives an output light from the optical amplification medium, a monitor that detects a power level of an output light from the optical loss medium, a controller that controls a power of the excitation light such that the power level of the output light detected by the monitor is at a target value, and a receiver that receives the output light from the optical loss medium, the output light not being optically amplified. | 08-23-2012 |
| 20120229887 | OPTICAL FIBER AMPLIFIER WITH IMPROVED PERFORMANCE - A method for controlling a variation in gain in an optical amplifier stage and an optical amplifier. The optical amplifier stage includes a pumping device for providing pumping power and a control unit for determining a change in an input power of the optical amplifier. The method includes the steps of determining a change in an input power of the optical amplifier, adjusting a pumping power of the pumping device to a first power level for a predetermined period of time and adjusting the pumping power of the pumping device to a second power level. The second power level is able to drive the amplifier gain to a predetermined gain value after the change in the input power occurred. | 09-13-2012 |
| 20120262780 | MULTIMODE OPTICAL AMPLIFIER WITH CLOSE-LOOP MODAL GAIN CONTROL - Systems and methods for amplification are shown that include a pump preparation module configured to provide a pump output that includes a plurality of pump modes; an amplification module configured to accept a multimode signal input and the pump output, such that the pump output causes an amplification of a plurality of modes in the signal input to produce an amplified signal output; and a gain control module configured to adjust a balance of the plurality of pump modes in the pump output to produce a predetermined amplified signal output. | 10-18-2012 |
| 20120300288 | LIGHT AMPLIFIER AND LASER PROCESSING DEVICE - A laser processing device includes a light amplifying fiber, a seed semiconductor laser (LD) for pulsing seed light multiple times during an emission period, an excitation LD for generating the exciting light of power at a first level during a non-emission period immediately before the emission period and generating the exciting light of power at a second level higher than the first level during the emission period, a light receiving element and a peak value detector for detecting power of an output light pulse which is output from the light amplifying fiber, and a control device. The control device controls the power of the exciting light of the non-emission period based on the detected value from the peak value detector to cause the power of first output light pulses which are generated during the emission period to be the same as the power of final output light pulses. | 11-29-2012 |
| 20130170019 | CONTROL METHOD AND MEASURING METHOD OF SEMICONDUCTOR OPTICAL AMPLIFIER, AND SEMICONDUCTOR OPTICAL AMPLIFIER DEVICE - A control method of a semiconductor optical amplifier includes: controlling a driving current of the semiconductor optical amplifier in a region where a light output intensity decreases in accordance with increasing of the driving current, a drive current in the region being higher than a drive current in a region where a light output intensity increases in accordance with increasing of the driving current. | 07-04-2013 |
| 20130222890 | EXCITATION LIGHT DISTRIBUTION DEVICE, EXCITATION LIGHT DISTRIBUTION METHOD, OPTICAL AMPLIFICATION SYSTEM AND NODE DEVICE - For the purpose of reducing the cost and power consumption of an optical amplification system provided with an optical amplifier, an excitation light distribution device of the present invention comprises an excitation light source output unit which outputs excitation light, an optical branching unit with variable branching ratio which branches and outputs the excitation light, and a control unit which, on the basis of information on an optical signal to be amplified by the excitation light outputted by the optical branching unit, controls at least either the branching ratio of the optical branching unit or the optical output power of the excitation light source output unit. | 08-29-2013 |
| 20150116816 | Compact Single Frequency Laser - A single frequency laser system is configured with an elongated housing extending along a longitudinal axis and having opposite axially spaced upstream and downstream ends. The housing encloses a laser chip configured to emit a radiation which propagates along a light path and emitted through the downstream faucet thereof. One or more spaced frequency discriminators are mounted in the housing downstream from the chip so as to define an external resonant cavity with the upstream faucet of the of the laser chip. At least two or more separate thermoelectric coolers (“TEC”) are mounted in the housing to control the chip arid discriminators so that the system emits radiation at the desired frequency. | 04-30-2015 |
| 20160204568 | LASER MODULE | 07-14-2016 |
| 359337120 | Using number of signals | 2 |
| 20100060978 | METHOD AND APPARATUS FOR CONTROLLING AND PROTECTING PULSED HIGH POWER FIBER AMPLIFIER SYSTEMS - An electronic circuit for controlling a laser system consisting of a pulse source and high power fiber amplifier is disclosed. The circuit is used to control the gain of the high power fiber amplifier system so that the amplified output pulses have predetermined pulse energy as the pulse width and repetition rate of the oscillator are varied. This includes keeping the pulse energy constant when the pulse train is turned on. The circuitry is also used to control the temperature of the high power fiber amplifier pump diode such that the wavelength of the pump diode is held at the optimum absorption wavelength of the fiber amplifier as the diode current is varied. The circuitry also provides a means of protecting the high power fiber amplifier from damage due to a loss of signal from the pulse source or from a pulse-source signal of insufficient injection energy. | 03-11-2010 |
| 20140177037 | EXTENDED DYNAMIC RANGE OPTICAL AMPLIFIER - An extended dynamic range optical amplifier, a method of operation, and a line amplifier configuration include an optical amplifier that can be optimized for high or low span loss conditions by switching an internal stage in or out of an internal light path within the amplifier. The extended dynamic range optical amplifier can include a low gain mode and a high gain mode with an internal switch to switch out a gain mid-stage in a low gain mode to extend the useful dynamic range of the amplifier. Further, the extended dynamic range optical amplifier can use residual pump power from an initial stage to pump the gain mid-stage in the high gain mode. Additionally, the extended dynamic range optical amplifier includes remapping of gain in the initial stage and the gain mid-stage to optimize the amplifier noise performance based on the maximum output power of the amplifier. | 06-26-2014 |
| 359337130 | Adjusting input signal power | 3 |
| 20080198445 | METHODS AND SYSTEMS FOR GAIN CONTROL IN PULSED OPTICAL AMPLIFIERS - A method of operating an amplifier system includes providing a pump signal at a pump wavelength. The pump signal is a function of a pump power. The method also includes providing an input signal at a signal wavelength and coupling the pump signal and the input signal to an optical amplifier. The optical amplifier includes a gain medium characterized by a gain value at the signal wavelength. The method further includes amplifying the input signal to provide an output signal, detecting a feedback signal related to the gain value, and modifying the pump power based on the detected feedback signal. | 08-21-2008 |
| 20100091357 | CONTROL APPARATUS OF OPTICAL AMPLIFIER - A control apparatus of an optical amplifier includes a monitoring section that measures power of light inputted to the optical amplifier, a power-wavelength characteristics variable section that is operable to change a wavelength characteristic of power of the light inputted, a wavelength number decrease recognition section that compares the value of the power of light measured by the monitoring section with a predetermined threshold, and a control section that controls the power-wavelength characteristics variable section when the wavelength number decrease recognition section judges that the value of the power of light falls below the threshold. | 04-15-2010 |
| 20140139906 | OPTICAL AMPLIFIER AND TRANSMISSION SYSTEM - An optical amplifier includes: a first amplifier amplifying a signal light by a first excitation light; a variable optical attenuator attenuating the signal light; a second amplifier amplifying the signal light by a second excitation light; a mode selector selecting one of first and second modes; a gain controller, in first mode, controlling first and second excitation lights so that a gain of power of the signal light becomes constant; a first output controller, in second mode, controlling the first excitation light; a second output controller that, in second mode, controlling the second excitation light so that a spontaneous emission light having fixed level is outputted; and an attenuation controller controlling an attenuation of the variable optical attenuator according to an input level of the signal light in first mode, and controlling the attenuation to become a given value larger than a value of first mode in second mode. | 05-22-2014 |
