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公开(公告)号：US11868026B2
公开(公告)日：2024-01-09
申请号：US17889951
申请日：2022-08-17
申请人： Fujitsu Limited
发明人： Tomoyuki Akiyama , Takeshi Hoshida , Jun Matsui , Shinsuke Tanaka
CPC分类号： G02F7/00 , G02F1/3137
摘要： An optical analog-to-digital (AD) converter includes, wherein the optical AD converter converts an analog signal of information included in inputted signal light into a digital signal, and is formed of N stages corresponding to a number N of bits of the digital signal, optical waveguides configured to respectively guide the signal light, base light obtained by branching local light, and reference light obtained by branching the local light, a light receiver configured to detect and compare light levels of the signal light and the reference light, and output a binary comparison result, and an optical modulator configured to variably control a light level of the base light, based on the binary comparison result, in each stage of the N stages, wherein an output variably controlled of the optical modulator is multiplexed with the reference light of a next stage.
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公开(公告)号：US11791906B2
公开(公告)日：2023-10-17
申请号：US17835504
申请日：2022-06-08
申请人： FUJITSU LIMITED
CPC分类号： H04B10/6166 , G02B6/12007 , H04B10/6162
摘要： An optical demultiplexing device includes a light source, a demultiplexer, a plurality of converters, a detector, a switch, and a controller, wherein the demultiplexer includes a plurality of asymmetric Mach-Zehnder interferometers (AMZ) each of which lengths of a pair of arms are different from each other, the plurality of AMZs are coupled to each other so that a plurality of wavelength lights input from the light source is demultiplexed and respectively output to the converters different from each other, and the controller controls the light source so that the plurality of wavelength lights is sequentially input to the demultiplexer one by one, and controls the switch so that an electrical signal detected by the detector is output to an output destination according to a wavelength light of a conversion source of the electrical signal.
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公开(公告)号：US11588572B2
公开(公告)日：2023-02-21
申请号：US17515702
申请日：2021-11-01
申请人： FUJITSU LIMITED
发明人： Tomoyuki Kato , Shigeki Watanabe , Takeshi Hoshida
摘要： An optical transmission device includes a first wavelength multiplexer, a second wavelength multiplexer, a wavelength converter and a third wavelength multiplexer. The first wavelength multiplexer multiplexes optical signals in a first wavelength band to generate first wavelength multiplexed light. The second wavelength multiplexer multiplexes optical signals in the first wavelength band to generate second wavelength multiplexed light in a first polarization. The wavelength converter converts a wavelength of the second wavelength multiplexed light from the first wavelength band into a second wavelength band by a cross phase modulation among the second wavelength multiplexed light, first pump light in a second polarization and second pump light in the second polarization. The second polarization is orthogonal to the first polarization. The third wavelength multiplexer multiplexes the second wavelength multiplexed light whose wavelength has been converted by the wavelength converter and the first wavelength multiplexed light.
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公开(公告)号：US20220109506A1
公开(公告)日：2022-04-07
申请号：US17364929
申请日：2021-07-01
申请人： FUJITSU LIMITED
IPC分类号： H04B10/564 , H04B10/61 , H04B10/079 , G02F1/21 , G02F1/01
摘要： An optical transmitter includes: a modulator, square law detector, and a processor. The modulator generates an optical signal indicating transmission data. The square law detector detects an intensity of the optical signal using a photodetector and output first intensity data indicating the detected intensity. The processor calculates, based on the transmission data, an electric field of the optical signal generated by the modulator by using parameters pertaining to a state of the modulator. The processor calculates second intensity data indicating the intensity of the optical signal based on the calculated electric field. The processor updates the parameters so as to reduce a difference between the first intensity data and the second intensity data. The processor controls the state of the modulator based on the parameters.
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公开(公告)号：US20220070555A1
公开(公告)日：2022-03-03
申请号：US17360002
申请日：2021-06-28
申请人： FUJITSU LIMITED
摘要： A transmission device including a demultiplexer configured to demultiplex a multiplexed light obtained by multiplexing the plurality of wavelength division multiplexing (WDM) optical signals including different wavelength bands into the plurality of WDM optical signals, a plurality of optical amplifiers configured to amplify the plurality of WDM optical signals, respectively, a wavelength converter configured to convert a first wavelength band of the wavelength bands of at least a first WDM optical signal of the plurality of WDM optical signals amplified by the plurality of optical amplifiers into a second wavelength band of the wavelength bands of a second WDM optical signal of the plurality of WDM optical signals so that the second wavelength band does not overlap among the wavelength bands, and a multiplexer configured to multiplex the plurality of WDM optical signals which include the wavelength bands converted by the wavelength converter.
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公开(公告)号：US20200264492A1
公开(公告)日：2020-08-20
申请号：US16781079
申请日：2020-02-04
申请人： FUJITSU LIMITED
发明人： GOJI NAKAGAWA , Tomoyuki Kato , Takeshi Hoshida , Masaaki Kawai
摘要： A wavelength converter includes an excitation light source outputting excitation light, a beam splitter receiving an input of the excitation light and an input of the optical signal and to divide both the inputted excitation light and the inputted optical signal into a first polarization component and a second polarization component, a non-linear optical fiber as a non-polarization-maintaining fiber, an accommodation section securing and accommodating the non-linear optical fiber, a first collimator lens disposed between the beam splitter and a first end of the non-linear optical fiber, and a second collimator lens disposed between the beam splitter and a second end of the non-linear optical fiber, wherein the optical signal is inputted to the beam splitter from a direction different from the input of the excitation light.
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公开(公告)号：US10439732B2
公开(公告)日：2019-10-08
申请号：US15685205
申请日：2017-08-24
申请人： FUJITSU LIMITED
发明人： Tomofumi Oyama , Takeshi Hoshida , Hisao Nakashima
IPC分类号： H04B10/61 , H04B10/077 , H04B10/63
摘要： A receiving device receives a received signal in which a data signal, modulated by using a phase modulation method, and a pilot signal are time-multiplexed. The receiving device includes a synchronizing circuit that synchronizes the phase of the received signal. The synchronizing circuit extracts a pilot signal from the received signal. The synchronizing circuit estimates a phase error by comparing the extracted pilot signal and a predetermined pattern. The synchronizing circuit conducts phase rotation on constellation points of the received signal in accordance with the reference phase, obtained from the phase error, and the phase in the modulation method related to the received signal. The synchronizing circuit estimates a phase estimate value of the received signal in accordance with the constellation points, on which phase rotation has been conducted. The synchronizing circuit compensates for a phase error of the received signal in accordance with the phase estimate value.
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公开(公告)号：US10429721B2
公开(公告)日：2019-10-01
申请号：US16358622
申请日：2019-03-19
申请人： FUJITSU LIMITED
发明人： Tomoyuki Kato , Shigeki Watanabe , Takeshi Hoshida
摘要： A wavelength conversion device that converts input signal light having a first frequency into output signal light having a second frequency, includes: a control-light generator that outputs first continuous oscillation light and second continuous oscillation light; and a nonlinear optical medium that cross-phase modulates the input signal light with the first continuous oscillation light and the second continuous oscillation light and generates the output signal light, wherein the control-light generator outputs the first continuous oscillation light and the second continuous oscillation light to have polarized waves in directions orthogonal to each other and have a frequency interval equal to a difference between the first frequency and the second frequency and controls, based on intensity of the output signal light, timings of modulation of phases of the first continuous oscillation light and the second continuous oscillation light to be aligned with each other.
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公开(公告)号：US10277328B2
公开(公告)日：2019-04-30
申请号：US15637389
申请日：2017-06-29
申请人： FUJITSU LIMITED
IPC分类号： H04B10/61 , H04J14/06 , G02B6/42 , H04B10/2507 , H04L7/00 , G03H1/00 , G02B6/12 , H04J14/02 , G02B6/00
摘要： A signal processing device processes an electric field information signal indicating a polarization multiplexed optical signal in which different modulation formats are used. A first optical signal transmitted in a first polarization component and a second optical signal transmitted in a second polarization component are multiplexed in the polarization multiplexed optical signal. The signal processing device includes a generator and a compensation circuit. The generator selects the first polarization component or the second polarization component based on modulation formats of the first and second optical signals, and generates a compensation value for compensating for an electric field information signal of a selected polarization component based on the electric field information signal of the selected polarization component. The compensation circuit compensates for electric field information signals of the first and second polarization components using the compensation value generated by the generator.
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公开(公告)号：US10277313B2
公开(公告)日：2019-04-30
申请号：US15403589
申请日：2017-01-11
申请人： FUJITSU LIMITED
发明人： Hisao Nakashima , Takeshi Hoshida
IPC分类号： H04B10/25 , H04J14/02 , H04B10/079
摘要： There is provided a transmission apparatus configured to receive a frequency-division multiplexed optical signal generated by modulating carrier light based on a plurality of frequency-division multiplexed subcarrier signals, the transmission apparatus including: a processor configured to: extract a plurality of subcarrier signals of the plurality of frequency-division multiplexed subcarrier signals from the frequency-division multiplexed optical signal; calculate signal qualities of the plurality of subcarrier signals; detect a deviation of the signal qualities between the plurality of subcarrier signals; and perform a frequency control of the carrier light generated by an optical source of a transmission apparatus configured to transmit the frequency-division multiplexed optical signal, based on the deviation of the signal qualities.
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