WO2023162207A1 - Émetteur optique et procédé d'émission - Google Patents

Émetteur optique et procédé d'émission Download PDF

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Publication number
WO2023162207A1
WO2023162207A1 PCT/JP2022/008228 JP2022008228W WO2023162207A1 WO 2023162207 A1 WO2023162207 A1 WO 2023162207A1 JP 2022008228 W JP2022008228 W JP 2022008228W WO 2023162207 A1 WO2023162207 A1 WO 2023162207A1
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Prior art keywords
optical
electrical signal
output light
phase
output
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PCT/JP2022/008228
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English (en)
Japanese (ja)
Inventor
陽一 深田
利明 下羽
暁弘 田邉
遼 宮武
智暁 吉田
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日本電信電話株式会社
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Priority to PCT/JP2022/008228 priority Critical patent/WO2023162207A1/fr
Publication of WO2023162207A1 publication Critical patent/WO2023162207A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/50—Transmitters
    • H04B10/516—Details of coding or modulation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/60—Receivers
    • H04B10/61—Coherent receivers
    • H04B10/64—Heterodyne, i.e. coherent receivers where, after the opto-electronic conversion, an electrical signal at an intermediate frequency [IF] is obtained

Definitions

  • the present invention relates to an optical transmission device and a transmission method.
  • FIG. 5 shows an example of a network configuration of a conventional FTTH type CATV system 1.
  • the FTTH type CATV system 1 includes, for example, a head end 100 (Head-End), an optical transmitter 200 (Tx), an amplifier 300 (V-OLT), and each subscriber's home. and an optical receiving device 400 (V-ONU) installed in, for example.
  • Head-End head end 100
  • Tx optical transmitter 200
  • V-OLT amplifier 300
  • V-ONU optical receiving device 400
  • the head end 100 receives radio waves carrying video signals transmitted from broadcasting stations via transmission towers on the ground, artificial satellites, etc., and adjusts the received radio waves such as amplification.
  • the headend 100 then outputs an electrical signal based on the video signal to the optical transmission device 200 .
  • the optical transmission device 200 converts the obtained electrical signal into an optical signal, and transmits the optical signal to an optical transmission line constructed with optical fibers.
  • the optical transmission line is divided into a section of the relay network 500 and a section of the access network 600 .
  • the relay network 500 is a communication network that connects the optical transmitter 200 and the access network 600 .
  • amplifiers 300 functioning as relay amplifiers are configured in multiple stages when the transmission distance is long.
  • Each amplifier 300 (V-OLT) transmits the amplified optical signal to another amplifier 300 in the subsequent stage, or to equipment such as the optical receiver 400 (V-ONU) within the section of the access network 600.
  • an optical coupler splits the optical signal and sends it to both the other amplifier 300 in the subsequent stage and the equipment in the section of the access network 600 .
  • the access network 600 is a communication network that connects the relay network 500 and each optical receiver 400 that terminates the optical signal.
  • the access network 600 generally has a PON (Passive Optical Network) configuration in order to distribute the optical signal output from the relay network 500 to the optical receivers 400 installed in the homes of a plurality of subscribers. Applies.
  • an amplifier (not shown) is also provided in the access network 600 for the purpose of compensating the loss caused by the distribution of the optical signal due to the PON configuration and the loss caused by the branching of the optical signal by the amplifier 300. amplifier) may be used.
  • an FM (Frequency Modulation) batch conversion system is used as an optical transmission system (see, for example, Non-Patent Document 1).
  • the optical transmission device 200 receives the electrical signals of frequency-multiplexed multi-channel video output from the head end 100, and collectively converts the electrical signals into one-channel broadband frequency modulation ( FM) signal. Furthermore, the optical transmission device 200 converts the converted FM signal into an optical signal by intensity modulation, and transmits the optical signal to the optical transmission line.
  • the optical receiver 400 upon receiving an optical signal from the optical transmission line, the optical receiver 400 converts the optical signal into an electrical FM signal and demodulates it. As a result, the optical receiver 400 can extract the electric signal of the frequency-multiplexed multi-channel video.
  • FIG. 6 shows the configuration of an optical transmitter 200b (Tx) disclosed in Non-Patent Document 2.
  • the frequency-multiplexed multi-channel electrical signals are separately input to the optical transmission device 200b for each band.
  • the electrical signal A is input to the electrical signal input terminal 11 and the electrical signal B is input to the electrical signal input terminal 12 .
  • the electrical signal A is input to the optical phase modulator 31 connected to the rear stage of the laser diode 21 (LD) to phase-modulate the optical signal.
  • the electrical signal B is split into two by the splitter 8 and then directly modulated into an optical signal by the laser diodes 21 and 22 .
  • Frequency chirping occurs (ie, frequency modulation occurs) by directly modulating the optical signal with the input signal.
  • a phase shifter 9 on one side of the electrical signal B split by the distributor 8
  • electrical signals having opposite phases are sent to the laser diodes 21 and 22, respectively. You can make it enter. This suppresses the remaining intensity modulation component.
  • the optical signals output from the laser diodes 21 and 22 are multiplexed by the optical multiplexer 4 and input to the photodiode 51 (PD).
  • the photodiode 51 performs optical heterodyne detection, and the photodiode 5 outputs an FM signal centered at a frequency equal to the oscillation frequency difference between the laser diodes 21 and 22 .
  • the FM signal is input to the optical intensity modulator 6 and intensity-modulates the output light from the laser diode 23 for transmission.
  • a signal light generated by intensity modulation is transmitted to the optical receiver 400 through a transmission fiber.
  • FIG. 13 is a block diagram showing an example of the configuration of a conventional optical transmitter 200. As shown in FIG. However, components not directly related to the modulation of the electrical signal A are omitted from the description.
  • the electric field E 1 (t) of the output light from the optical phase modulator 31 and the electric field E 2 (t) of the output light from the laser diode 22 at the input end of the photodiode 51 are expressed by the following equations (1) and (2) can be expressed by the formula.
  • E 1 (t) and E 2 (t) are the instantaneous values of the electric field at time t.
  • E 1 and E 2 are the maximum values of the electric field.
  • ⁇ 1 and ⁇ 2 are the angular frequencies of the electric field when unmodulated.
  • the electric signal ⁇ 1 (t) is an electric signal input from the electric signal input terminal 11 (however, this electric signal is subject to losses and phase shift changes between the electric signal input terminal 11 and the optical phase modulator 31). is the same as the electrical signal input to the optical phase modulator 31).
  • m is a constant representing the modulation efficiency of the optical phase modulator 31 .
  • Heterodyne detection is performed in the photodiode 51 based on these optical inputs.
  • the current I(t) of the output electrical signal (heterodyne detection signal) is represented by the following equation (3).
  • ⁇ that is, this operator gives an averaged value to the components that fluctuate at angular frequencies equal to or higher than ⁇ 1 or ⁇ 2 .
  • the role of the laser diode 21 is to output carrier light for superimposing the electrical signal ⁇ 1 (t). Also, as is clear from the above equation (2), the role of the laser diode 22 is to output local light for coherently receiving the electric signal ⁇ 1 (t).
  • the phase is proportional to the electric signal ⁇ 1 (t) input to the optical phase modulator 31. It is in the form of modulation.
  • ITU-T J.185 Transmission equipment for transferring multi-channel television signals over optical access networks by frequency modulation conversion
  • International Telecommunication Union June 2012.
  • Toshiaki Shimoba, et al. "Optical Video Distribution Technology Using FM Batch Conversion Method"
  • the two laser diodes 21 and 22 for directly modulating the electrical signal B are required to have very high linearity between the bias current and the oscillation frequency from the viewpoint of improving the distortion characteristics of the signal. be. Therefore, there is a problem that the sorting cost of each laser diode becomes very high. In order to solve this problem, a method of processing all electric signals only by phase modulation without performing direct modulation in the laser diodes 21 and 22 is conceivable.
  • FIG. 7 is a diagram showing a configuration example of an optical transmission device 200c configured to process all electrical signals only by phase modulation.
  • the configuration of the optical transmission device 200c is the same as the configuration of the conventional optical transmission device 200b shown in FIG.
  • the present invention has been made in view of the above technical background, and aims to provide a technique capable of improving noise characteristics and distortion characteristics at the same time.
  • One aspect of the present invention includes a distributor that distributes a first electrical signal input to an electrical signal input section into a second electrical signal and a third electrical signal, and a splitter that splits the third electrical signal 180 degrees.
  • a phase shifter for shifting a phase; a first optical phase modulator for phase-modulating output light from a first laser diode based on the second electrical signal output from the distributor; and the phase shifter.
  • a second optical phase modulator for phase-modulating the output light from the second laser diode based on the third electrical signal output from the device; and the output light from the first optical phase modulator.
  • an optical multiplexer for multiplexing the output light from the second optical phase modulator and splitting the multiplexed output light into a first output light and a second output light; and the optical multiplexer.
  • a first photodiode that converts the first output light from the optical combiner into a first heterodyne detection signal
  • a second photodiode that converts the second output light from the optical multiplexer into a second heterodyne detection signal.
  • the first heterodyne detection signal and the second heterodyne output from a connection point between a photodiode and an anode of one of the first photodiode and the second photodiode and a cathode of the other. and an optical intensity modulator that intensity-modulates the output light from the third laser diode based on the combined component with the detection signal.
  • FIG. 1 is a block diagram showing the configuration of an optical transmitter 200a according to an embodiment of the present invention
  • FIG. 1 is a block diagram showing an example of the configuration of a balanced receiver according to an embodiment of the present invention
  • FIG. 4 is a flow chart showing the operation of the optical transmitter 200a according to the embodiment of the present invention
  • FIG. 4 is a diagram for explaining the phase relationship between two output lights in a 2-input 2-output optical multiplexer 41
  • 1 is a block diagram showing an example of a network configuration of an FTTH-type CATV system
  • FIG. FIG. 11 is a block diagram showing an example of the configuration of a conventional optical transmission device 200b
  • FIG. 11 is a block diagram showing an example of the configuration of a conventional optical transmission device 200c;
  • Embodiments of the present invention will be described below.
  • the system configuration of the network system in each embodiment described below is the same as the network configuration of the conventional FTTH-type CATV system 1 shown in FIG.
  • FIG. 1 is a block diagram showing the configuration of an optical transmitter 200a according to an embodiment of the present invention.
  • the optical transmitter 200a includes an electrical signal input terminal 11, a distributor 8, a phase shifter 9, three laser diodes (laser diodes 21 to 23) (LD), and two Optical phase modulators (optical phase modulators 31-32), a two-input two-output optical multiplexer 41, two photodiodes (photodiodes 51-52) (PD), an optical intensity modulator 6, and an optical and a signal output terminal 7 .
  • An electrical signal A is taken into the optical transmission device 200 a from the electrical signal input terminal 11 and input to the input terminal of the distributor 8 .
  • the distributor 8 divides the input electric signal A into two. One side of the electric signal A split into two by the distributor 8 is input to the input terminal of the optical phase modulator 31 . The other half of the electric signal A divided into two is input to the input terminal of the phase shifter 9 .
  • the electrical signal A input to the phase shifter 9 is input to the input terminal of the optical phase modulator 32 after being phase-shifted by 180 degrees.
  • the light output from the laser diode 21 is phase-modulated by the electrical signal A in the optical phase modulator 31 .
  • the light output from the laser diode 22 is phase-modulated by the phase-shifted electrical signal A in the optical phase modulator 32 .
  • These phase-modulated lights are multiplexed by a 2-input 2-output optical combiner 41 and demultiplexed, and input to photodiodes 51 and 52, respectively.
  • Heterodyne detection is performed in the photodiodes 51 and 52, respectively. Electrical signals (heterodyne detection signals) output from the photodiodes 51 and 52 are input to input terminals of the optical intensity modulator 6 .
  • the light output from the laser diode 23 is intensity-modulated in the optical intensity modulator 6 based on the composite component of the electrical signals (heterodyne detection signals) output from the photodiodes 51 and 52, respectively.
  • the intensity-modulated signal light is output from the optical signal output terminal 7 to the outside of the optical transmitter 200a.
  • FIG. 2 is a diagram showing the configuration of a balanced receiver according to an embodiment of the present invention.
  • the two photodiodes 51 and 52 described above constitute a balanced receiver.
  • As a method of configuring a balanced receiver for example, as shown in FIG. (A constant voltage source, ground, or the like connected to the cathode of the photodiode 51 and the anode of the photodiode 52 is not shown in FIG. 15(a)).
  • Heterodyne detection is performed in the photodiodes 51 and 52, respectively.
  • the electrical signals (heterodyne detection signals) respectively output from the photodiodes 51 and 52 are combined and then input to the input terminal of the optical intensity modulator 6 .
  • the light output from the laser diode 23 is intensity-modulated in the light intensity modulator 6 based on the composite component of the electrical signals (heterodyne detection signals) output from the photodiodes 51 and 52, respectively.
  • the intensity-modulated signal light is output from the optical signal output terminal 7 to the outside of the optical transmitter 200a.
  • the optical transmission device 200h detects the amplitude of the electrical signal input from each electrical signal input terminal, or The bias may be adjusted to control the amount of modulation. Therefore, an amplifier, an attenuator, and a bias tee may be used in the optical transmission device 200h.
  • the electric field E′ 1 (t) of the output light from the optical phase modulator 31 and the electric field E′ 2 (t) of the output light from the optical phase modulator 32 at the input end of the optical multiplexer 41 are given by the following (4 ) and (5) (details will be explained in the appendix below).
  • E′ 1 (t) and E′ 2 (t) are the instantaneous values of the electric field at time t.
  • ( ⁇ 2 ⁇ E 1 + ⁇ 2 ⁇ e 1 (t)) and ( ⁇ 2 ⁇ E 2 + ⁇ 2 ⁇ e 2 (t)) are the amplitudes of the electric fields.
  • ⁇ 2 ⁇ E 1 and ⁇ 2 ⁇ E 2 are constants representing the output electric field amplitudes of the laser diodes 21 and 22 .
  • ⁇ 2 ⁇ e 1 (t) and ⁇ 2 ⁇ e 2 (t) are variables representing fluctuations in the output electric field amplitudes of the laser diodes 21 and 22 at time t.
  • ⁇ 1 and ⁇ 2 are the angular frequencies of the electric field when unmodulated.
  • the electric signal ⁇ 1 (t) is an electric signal input from the electric signal input terminal 11 (where the terms including ⁇ 1 (t) in the equation (4) or (5) are added or subtracted, respectively). depending on the presence or absence of the phase shifter 9).
  • m is a constant representing the modulation efficiency of the optical phase modulators 31 and 32 .
  • the optical multiplexer 41 in general, when light input from terminal a (or terminal b) is demultiplexed and output from terminals A and B, the phases of the output lights have a relative difference of 90 degrees. It will be.
  • the electric field at the input end of the photodiode 51 of the light transmitted through the optical multiplexer 41 and output from the terminal A is the component E A1 (t) derived from the optical phase modulator 31 and the component E A2 derived from the optical phase modulator 32
  • Each (t) can be represented by the following equations (6) and (7), respectively (details will be explained in the appendix described later).
  • the electric field at the input end of the photodiode 52 of the light transmitted through the optical multiplexer 41 and output from the terminal B is the component E B1 (t) derived from the optical phase modulator 31 and the component E B2 derived from the optical phase modulator 32
  • Each (t) can be represented by the following equations (8) and (9).
  • heterodyne detection is performed based on the light input represented by the formulas (6) and (7).
  • the current I A (t) of the output heterodyne detection signal is expressed by the following equation (10) using equations (6) and (7).
  • ⁇ ⁇ . That is, this operator gives an averaged value to the components that fluctuate at angular frequencies equal to or higher than ⁇ 1 or ⁇ 2 . Since e 1 (t) and e 2 (t) are very small, the values of e 1 (t) 2 , e 2 (t) 2 and e 1 (t)e 2 (t) are 0 and
  • ⁇ ⁇ . That is, this operator gives an averaged value to the components that fluctuate at angular frequencies equal to or higher than ⁇ 1 or ⁇ 2 . Since e 1 (t) and e 2 (t) are very small, the values of e 1 (t) 2 , e 2 (t) 2 and e 1 (t)e 2 (t) are 0 and
  • the currents I A (t) and I B (t) output from the photodiodes 51 and 52 , respectively, are coupled as described above to form an electrical signal of the current I(t), and then sent to the optical intensity modulator 6 . is entered.
  • This current I(t) (heterodyne detection signal) is represented by the following equation (12).
  • the configuration of a balanced receiver with two photodiodes as opposed to the configuration with only one photodiode, effectively
  • the modulation efficiency increases from m to 2m. That is, the power of the electric signal A required for the same modulation as in the conventional art is halved. Therefore, according to the optical transmission device 200a according to the embodiment, the distortion generated by the amplifier (not shown) arranged between the electrical signal input terminal 11 and the optical phase modulator 31 is reduced, and the distortion characteristics are improved. has the effect of
  • an optical multiplexer/demultiplexer multiplexes one signal light and one local oscillation light (non-modulated light), and the noise (relative intensity noise) generated from the local oscillation light ) is known (Reference: Masaru Iwashita, "Development of Coherent Optical Communication Technology", Journal of the Optical Society of Japan, Vol. 38, No. 5, p.239, May 2009).
  • this reference like the optical transmission device 200a in the embodiment, two signal lights are multiplexed and demultiplexed, and noise (E 1 e 1 (t) and E 2 e 2 (t)) is not disclosed, and neither the configuration nor the effect thereof is suggested.
  • FIG. 3 is a flow chart showing the operation of the optical transmitter 200a according to the embodiment of the present invention.
  • the operation of the optical transmission device 200a shown in this flowchart starts when the electrical signal A is input to the electrical signal input terminal 11.
  • the electrical signal input terminal 11 inputs the electrical signal A to the distributor 8 .
  • the distributor 8 After dividing the electric signal A into the electric signals A1 and A2, the distributor 8 inputs the electric signal A1 to the optical phase modulator 31 and the electric signal A2 to the phase shifter 9 . (Step S01).
  • the phase shifter 9 inputs the electrical signal A2 to the optical phase modulator 32 after phase-shifting the electrical signal A2 by 180 degrees. (Step S02).
  • the optical phase modulator 31 phase-modulates the light output from the laser diode 21 with the electrical signal A1 (step S03).
  • the optical phase modulator 32 phase-modulates the light output from the laser diode 22 with the electric signal A2 (step S04).
  • the optical multiplexer 4 multiplexes the output light from the optical phase modulator 31 and the output light from the optical phase modulator 32 . After that, the optical multiplexer 4 demultiplexes the multiplexed output light into first output light and second output light. The optical multiplexer 4 outputs the first output light to the photodiode 51 and the second output light to the photodiode 52 (step S05).
  • the photodiode 51 performs heterodyne detection on the first output light output from the optical multiplexer 41 (step S06). Also, the photodiode 52 performs heterodyne detection on the second output light output from the optical multiplexer 41 (step S07).
  • the optical intensity modulator 6 intensity-modulates the light output from the laser diode 23 based on the composite component of the electrical signal (heterodyne detection signal) output from the connection point between the photodiode 51 and the photodiode 52 (step S08). ).
  • the optical signal output terminal 7 outputs the intensity-modulated signal light to the relay network 500 (step S09).
  • FIG. 4 is a diagram for explaining the phase relationship between two output lights in the 2-input 2-output optical multiplexer 41 .
  • T be a transfer function that represents the relationship between the electric fields and the phases of the two input lights and the two output lights of the optical multiplexer 41 .
  • the changes in the electric field and phase when transmitting "from terminal a to terminal A” and the changes in the electric field and phase when transmitting "from terminal b to terminal B" are the same.
  • the changes in the electric field and phase during transmission "from terminal a to terminal B” and the changes in electric field and phase during transmission "from terminal b to terminal A" are the same. Therefore, the transfer function T has symmetry as represented by the following equation (13).
  • the output optical electric field from each of the terminals A and B of the optical multiplexer 41-1 (point 2) and the output optical electric field from each of the terminals A and B of the optical multiplexer 41-2 (point 3 ) is represented by the following equations (15) and (16) based on the above equations (13) and (14).
  • the optical transmission device 200a multiplexes two phase-modulated optical signals by the optical multiplexer 41, demultiplexes them, and divides them into electrical signals using the configuration of the balanced receiver. Convert to With such a configuration, the optical transmitter 200a can remove noise caused by fluctuations in the output field amplitude of the laser diode, and simultaneously improve noise characteristics and distortion characteristics.
  • the optical phase modulator 31 is connected after the laser diode 21, and the optical phase modulator 32 is connected after the laser diode 22, respectively.
  • the optical transmitter 200a inputs the input signal whose phase is inverted by the phase shifter 8 to one of the optical phase modulators (the optical phase shift modulator 32 in this embodiment).
  • the optical transmitter 200a multiplexes the lights output from the optical phase modulators 31 and 31 respectively by the optical multiplexer 41 and then demultiplexes them, and performs square-law detection by the photodiodes 51 and 52. .
  • the optical transmission device 200a can reduce the input signal voltage to the optical phase modulators 31 and 32 .
  • the optical transmission device 200a can be used even when the amplitude of the input signal to the optical phase modulators 31 and 32 increases due to, for example, the addition of channels or an increase in the band of the input signal. , the deterioration of signal quality can be made difficult to occur.
  • the optical transmission device includes a distributor, a phase shifter, a first optical phase modulator, a second optical phase modulator, an optical multiplexer, and a first photodiode. , a second photodiode, and an optical intensity modulator.
  • the optical transmission device is the optical transmission device 200a in the embodiment
  • the splitter is the splitter 8 in the embodiment
  • the phase shifter is the phase shifter 9 in the embodiment
  • the modulator is the optical phase modulator 31 in the embodiment
  • the second optical phase modulator is the optical phase modulator 32 in the embodiment
  • the optical multiplexer is the optical multiplexer 41 in the embodiment
  • the first photodiode is the photodiode 51 in the embodiment
  • the second photodiode is the photodiode 52 in the embodiment
  • the light intensity modulator is the light intensity modulator 6 in the embodiment.
  • the above distributor distributes the first electrical signal input to the electrical signal input section into the second electrical signal and the third electrical signal.
  • the electrical signal input unit is the electrical signal input terminal 11 in the embodiment
  • the first electrical signal is the electrical signal A in the embodiment
  • the second electrical signal is the electrical signal A1 in the embodiment
  • the third electrical signal is the electrical signal A2 in the embodiment.
  • the phase shifter described above phase-shifts the third electrical signal by 180 degrees.
  • the first optical phase modulator described above phase-modulates the output light from the first laser diode based on the second electrical signal output from the distributor.
  • the first laser diode is laser diode 21 in the embodiment.
  • the second optical phase modulator phase-modulates the output light from the second laser diode based on the third electrical signal output from the phase shifter.
  • the second laser diode is laser diode 22 in the embodiment.
  • the optical multiplexer multiplexes the output light from the first optical phase modulator and the output light from the second optical phase modulator, and combines the combined output light into the first output light and the second optical phase modulator. 2 output light.
  • the first output light is the output light from the terminal A of the optical multiplexer 41 in the embodiment
  • the second output light is the output light from the terminal B of the optical multiplexer 41 in the embodiment.
  • the first photodiode converts the first output light from the optical multiplexer into a first heterodyne detection signal.
  • the second photodiode converts the second output light from the optical multiplexer into a second heterodyne detection signal.
  • the optical intensity modulator includes a first heterodyne detection signal and a second heterodyne detection signal output from a connection point between the anode of one of the first photodiode and the cathode of the second photodiode and the cathode of the other.
  • the output light from the third laser diode is intensity-modulated based on the combined component with the detection signal.
  • the third laser diode is laser diode 23 in the embodiment.
  • the above optical transmission device may further include an amplifier that amplifies the first electrical signal or the second electrical signal when the first optical phase modulator is driven.
  • the above optical transmission device may further include an amplifier that amplifies the first electrical signal or the third electrical signal when the second optical phase modulator is driven.
  • the above optical transmission device may further include an attenuator that attenuates the first electrical signal or the second electrical signal when the first optical phase modulator is driven.
  • the above optical transmission device may further include an attenuator that attenuates the first electrical signal or the third electrical signal when the second optical phase modulator is driven.
  • the above optical transmission device may further include a bias tee for adjusting the bias of the first electrical signal or the second electrical signal when the first optical phase modulator is driven.
  • the above optical transmission device may further include a bias tee for adjusting the bias of the first electrical signal or the third electrical signal when the second optical phase modulator is driven.
  • a part or all of the optical transmission device 200a in the above-described embodiment may be realized by a computer.
  • a program for realizing this function may be recorded in a computer-readable recording medium, and the program recorded in this recording medium may be read into a computer system and executed.
  • the "computer system” referred to here includes hardware such as an OS and peripheral devices.
  • the term "computer-readable recording medium” refers to portable media such as flexible discs, magneto-optical discs, ROMs and CD-ROMs, and storage devices such as hard discs incorporated in computer systems.
  • “computer-readable recording medium” refers to a program that dynamically retains programs for a short period of time, like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. It may also include something that holds the program for a certain period of time, such as a volatile memory inside a computer system that serves as a server or client in that case. Further, the program may be for realizing a part of the functions described above, or may be capable of realizing the functions described above in combination with a program already recorded in the computer system. It may be implemented using a programmable logic device such as an FPGA (Field Programmable Gate Array).
  • FPGA Field Programmable Gate Array

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Abstract

Un émetteur optique comprend : un diviseur qui divise un premier signal électrique en un deuxième signal électrique et un troisième signal électrique ; un déphaseur qui déphase le troisième signal électrique de 180 degrés ; un premier modulateur de phase optique qui module la phase de la lumière de sortie provenant d'une première diode laser sur la base du deuxième signal électrique ; un second modulateur de phase optique qui module la phase de la lumière de sortie provenant d'une deuxième diode laser sur la base du troisième signal électrique ; un multiplexeur optique qui multiplexe la lumière de sortie provenant du premier modulateur de phase optique et la lumière de sortie provenant du second modulateur de phase optique pour les séparer en une première lumière de sortie et une seconde lumière de sortie ; et un modulateur d'intensité de lumière qui module l'intensité de la lumière de sortie provenant d'une troisième diode laser sur la base d'une composante synthétisée obtenue par synthèse d'un premier signal de détection hétérodyne et d'un second signal de détection hétérodyne qui sont émis depuis un point de connexion entre une anode soit d'une première photodiode, soit d'une seconde photodiode, et d'une cathode de l'autre de la première et de la seconde photodiode, la première photodiode convertissant la première lumière de sortie en un signal de détection hétérodyne et la seconde photodiode convertissant la seconde lumière de sortie en un signal de détection hétérodyne.
PCT/JP2022/008228 2022-02-28 2022-02-28 Émetteur optique et procédé d'émission WO2023162207A1 (fr)

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