WO2004070976A1 - 光伝送システム - Google Patents
光伝送システム Download PDFInfo
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- WO2004070976A1 WO2004070976A1 PCT/JP2004/001266 JP2004001266W WO2004070976A1 WO 2004070976 A1 WO2004070976 A1 WO 2004070976A1 JP 2004001266 W JP2004001266 W JP 2004001266W WO 2004070976 A1 WO2004070976 A1 WO 2004070976A1
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- optical
- signal
- optical signal
- polarization
- transmission
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- 230000003287 optical effect Effects 0.000 title claims abstract description 763
- 230000005540 biological transmission Effects 0.000 title claims abstract description 160
- 239000013307 optical fiber Substances 0.000 claims abstract description 143
- 238000012545 processing Methods 0.000 claims abstract description 52
- 230000010287 polarization Effects 0.000 claims description 168
- 238000006243 chemical reaction Methods 0.000 claims description 125
- 238000000926 separation method Methods 0.000 claims description 15
- 238000000034 method Methods 0.000 claims description 6
- 230000005577 local transmission Effects 0.000 claims description 5
- 230000010355 oscillation Effects 0.000 claims description 5
- 230000008569 process Effects 0.000 claims description 4
- 230000003321 amplification Effects 0.000 claims description 3
- 238000003199 nucleic acid amplification method Methods 0.000 claims description 3
- 239000002131 composite material Substances 0.000 claims description 2
- 238000005773 Enders reaction Methods 0.000 claims 1
- 238000010276 construction Methods 0.000 abstract description 5
- 230000008878 coupling Effects 0.000 description 15
- 238000010168 coupling process Methods 0.000 description 15
- 238000005859 coupling reaction Methods 0.000 description 15
- 239000004065 semiconductor Substances 0.000 description 13
- 238000010586 diagram Methods 0.000 description 11
- 239000000835 fiber Substances 0.000 description 7
- 238000005516 engineering process Methods 0.000 description 5
- 238000004891 communication Methods 0.000 description 3
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- 230000005684 electric field Effects 0.000 description 3
- 238000012423 maintenance Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 239000003990 capacitor Substances 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 239000010936 titanium Substances 0.000 description 2
- 208000025174 PANDAS Diseases 0.000 description 1
- 208000021155 Paediatric autoimmune neuropsychiatric disorders associated with streptococcal infection Diseases 0.000 description 1
- 240000000220 Panda oleosa Species 0.000 description 1
- 235000016496 Panda oleosa Nutrition 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- GQYHUHYESMUTHG-UHFFFAOYSA-N lithium niobate Chemical compound [Li+].[O-][Nb](=O)=O GQYHUHYESMUTHG-UHFFFAOYSA-N 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229940125730 polarisation modulator Drugs 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N titanium dioxide Inorganic materials O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- 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
- H04B10/25—Arrangements specific to fibre transmission
- H04B10/2575—Radio-over-fibre, e.g. radio frequency signal modulated onto an optical carrier
- H04B10/25752—Optical arrangements for wireless networks
- H04B10/25758—Optical arrangements for wireless networks between a central unit and a single remote unit by means of an optical fibre
-
- 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
- H04B10/25—Arrangements specific to fibre transmission
- H04B10/2507—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion
-
- 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
- H04B10/25—Arrangements specific to fibre transmission
Definitions
- the present invention relates to an analog optical transmission technology for optically transmitting an optical signal by modulating the intensity of the optical signal with a modulated electric signal, and particularly to a technology for suppressing a noise component generated in an optical transmission system.
- Non-Patent Document 1 discloses a technique for performing high-quality optical transmission in an optical transmission system that performs high-speed transmission using an optical fiber.
- an optical transmission system includes an optical transmitter and an optical receiver, and the optical transmitter and the optical receiver are connected by two optical fibers.
- An optical transmitter modulates the intensity of an optical signal to be transmitted to an optical receiver by a radio frequency signal to be transmitted (hereinafter, referred to as an “RF signal”). It generates two optical signals that have a reversed-phase relationship, and outputs the two generated optical signals to the optical receiving device via individual optical fibers.
- RF signal radio frequency signal to be transmitted
- an optical receiving device When an optical receiving device receives two optical signals from an optical transmitting device via individual optical fibers, it converts the two received optical signals into electric signals, and converts any one of the converted electric signals into an electric signal. Are reversed in phase and added to the other electric signal.
- the RF signals which are the intensity modulation components of the two optical signals received from the optical transmitter
- they are converted to electric signals, and when added, they become in phase and are added to each other. become.
- the two optical signal noise components received from the optical transmitting device are in phase, they become out of phase when they are added, and are canceled each other. As a result, high-quality optical transmission can be realized.
- the present invention provides an optical signal that transmits an optical signal from an optical transmitting device to an optical receiving device, performs a process of canceling a noise component mixed during transmission, and then outputs an output electric signal.
- the optical receiving device and the optical transmitting device are coupled by one optical fiber, an optical signal before intensity modulation is transmitted through the optical fiber, and the optical receiving device
- a first processing unit that intensity-modulates the modulated optical signal and converts the intensity-modulated components into two optical signals having phases opposite to each other, and a first and a second transmission light that transmits the optical signals whose intensity-modulated components have phases opposite to each other It is characterized by comprising a fiber and a second processing unit that converts each of the two optical signals into an electric signal at the transmission end, and inverts and amplifies to generate an output electric signal.
- the optical receiver modulates the intensity of the received optical signal to generate two optical signals in which the intensity modulation components are out of phase with each other, and combines the generated two optical signals. Each of them can be converted into an electric signal and inverted and amplified to generate an output electric signal.
- the optical receiving device does not need to receive two optical signals in which the intensity modulation components are out of phase with each other. That is, the optical transmitting device and the optical receiving device need not be connected to each other. There is no need to connect with two optical fibers, and construction costs are reduced.
- the two optical signals whose intensity modulation components are out of phase with each other are converted into electric signals, and one of the two converted electric signals is inverted, the electric signals of the two become in-phase and the noise components of each other become The phase can be reversed. As a result, when generating the output electric signal, the phase of the noise component is canceled, and a high-quality output electric signal can be generated.
- FIG. 1 is a block diagram showing a configuration of the optical transmission system 1.
- FIG. 2 is a diagram showing a configuration of the optical frequency conversion unit 202.
- FIG. 3 is a cross-sectional view of the optical frequency conversion unit 202.
- FIG. 4 is a block diagram showing the configuration of the balance-type photoelectric conversion unit 203.
- FIG. 5 is a block diagram showing a configuration of the optical transmission system 1A.
- FIG. 6 is a diagram illustrating the operation of the polarization scrambler 103A. ⁇
- FIG. 7 is a block diagram showing a configuration of the optical transmission system 1B.
- FIG. 8 is a diagram illustrating a configuration of the polarization control unit 205B.
- FIG. 9 is a block diagram showing a configuration of the optical transmission system 1C.
- the optical transmission system 1 includes an optical transmitter 10, an optical receiver 20, and an optical fiber 30.
- the optical transmitting device 10 and the optical receiving device 20 are connected by an optical fiber 30.
- the optical transmitter 10 converts an intermediate frequency signal (hereinafter, referred to as “IF signal”) into an optical signal, and transmits the converted optical signal to the optical receiver 20 via the optical fiber 30.
- the optical receiver 20 receives an optical signal from the optical transmitter 10 via the optical fiber 30, converts the IF signal into an RF signal using the received optical signal, and transmits the converted RF signal to the mobile phone 40.
- An IF signal is an electrical signal having a frequency different from the frequency of the RF signal, and generally has a lower frequency than the RF signal.
- the optical transmission device 10 includes an IF signal input unit 101 and an electro-optical conversion unit 102, as shown in FIG. ,
- the IF signal input unit 101 receives an input of an IF signal that is a signal to be transmitted to the optical receiver 20, and outputs the received IF signal to the electro-optical converter 102.
- the electro-optical conversion unit 102 is, specifically, a semiconductor laser module. Upon receiving an IF signal from the IF signal input unit 101, the electro-optical conversion unit 102 optically converts the received IF signal to generate an optical signal, and generates the generated optical signal. Is output to the optical receiver 20 via the optical fiber 30.
- a semiconductor laser module usually includes a laser chip, a monitor PD for controlling an optical signal to operate at a constant output, a Peltier cooler for controlling a temperature, an isolator for preventing reflected light, and first and second lenses.
- a semiconductor laser module usually includes a laser chip, a monitor PD for controlling an optical signal to operate at a constant output, a Peltier cooler for controlling a temperature, an isolator for preventing reflected light, and first and second lenses.
- the semiconductor laser module Upon receiving the IF signal, the semiconductor laser module converts the received IF signal into an optical signal using a laser chip to generate an optical signal.
- the generated optical signal passes through the first lens, the isolator, and the second lens in this order, and Output to fiber.
- the semiconductor laser module described above has an isolator, it is not limited to this.
- a semiconductor laser module without an isolator may be used.
- the semiconductor laser module passes the generated optical signal through the first lens and the second lens in this order, and outputs the signal to the optical fiber.
- a lens is not used and the optical fiber is directly coupled.
- the optical receiving device 20 includes an LO signal input unit 201, an optical frequency conversion unit 202, a balanced photoelectric conversion unit 203, and a transmission unit 204, and an optical frequency conversion unit 202.
- the balanced photoelectric conversion unit 203 are connected by optical fibers 210 and 211.
- the LO signal input unit 201 receives an input of a local oscillation signal (hereinafter, referred to as an “LO signal”) having a certain frequency in order to intensity-modulate the optical signal received from the optical transmission device 10, and receives the received LO signal. Output to the optical frequency conversion unit 202.
- LO signal a local oscillation signal
- the frequency of the L ⁇ signal is equivalent to the frequency of the RF signal (hereinafter, referred to as “RF frequency”).
- the optical frequency conversion unit 202 is, specifically, a Matsuhender type external modulator of a chirp type
- FIG. 2 shows a configuration of the optical frequency conversion unit 202
- FIG. 3 shows a configuration of XI-X2 in FIG. 4 shows a cross section of the optical frequency conversion unit 202.
- the optical frequency conversion unit 202 includes a lithium niobate crystal as shown in FIGS.
- LN Z-cut LN base layer 330, waveguide 301, hot electrode 310 and ground electrodes 311 and 312, termination resistor 320, polarizer 321 and LN Block 3 22, a glass gallery 323, 324, and a buffer layer 331 made of silicon dioxide.
- the waveguide 301 is formed by thermally diffusing titanium (Ti) to the surface of the LN base layer 330.
- One end of the waveguide 301 is connected to the optical fiber 30 via the polarizer 321, and the other end is a Y-branch 302, which is referred to as two waveguides (hereinafter, “first same waveguide” and “second waveguide”). ),
- the first and second waveguides are coupled at the coupling point 303, and after coupling, the two waveguides (hereinafter, “third waveguide”, “
- the fourth and third waveguides are connected to an optical fiber 210 and an optical fiber 211 via glass cavities 323 and 324, respectively.
- the length of the waveguide 301 from the receiving point where the waveguide 301 receives the optical signal from the optical fiber to the point where the waveguide 301 is branched into the first and second waveguides is a half of the complete coupling length. Minutes.
- the length from the coupling point 303 to the branch point into the third and fourth waveguides is set to half of the complete coupling length.
- the Y-branches 302 and 304 perform the same function as the 3 dB coupler. That is, the Y-branches 302 and 304 can divide the received optical power in half.
- the principle of splitting the optical power into halves is well-known, and a description thereof will be omitted.
- the hot electrode 310 and the ground electrode 311 of the optical frequency conversion unit 202 are connected to the two conductors branched by the Y branch 302.
- the arrangement is such that the ground electrode 311 is directly above the first waveguide and the hot electrode 310 is directly above the second waveguide because the arrangement is such that it is directly above the waveguide 301.
- the buffer layer 331 is provided between the hot electrode 310 and the ground electrodes 311 and 312, and the LN base layer 330 to avoid absorption loss of the light passing through the first and second waveguides by the electrode metal. .
- the buffer layer 331 between the hot electrode 310, the ground electrodes 311 and 312, and the LN base layer 330 is omitted to facilitate the configuration of the optical frequency conversion unit 202.
- the buffer layer 331 is provided between the hot electrode 310 and the ground electrodes 311 and 312, and the LN base layer 330, as shown in FIG.
- One end of the hot electrode 310 is connected to the LO signal input section 201, and the other end is
- the ground electrodes 311 and 312 are grounded.
- the optical frequency converter 202 receives an optical signal from the optical transmitter 10 via the optical fiber 30. Upon removal, the received optical signal is branched into a first waveguide and a second waveguide in the Y branch 302 so that the optical power of the received optical signal becomes equal. Next, the optical frequency conversion unit 202 applies the LO signal received by the L ⁇ signal input unit 201 to the hot electrode 310, and thereby between the hot electrode 310 and the ground electrode 311 and between the hot electrode 310 and the hot electrode. An electric field is generated between 310 and ground electrode 311. As a result, the refractive indexes of the first and second waveguides change, and the respective optical signals passing through the first and second waveguides undergo phase changes of ⁇ and 1 ⁇ , respectively.
- the optical frequency converter 202 couples and interferes the two phase-changed optical signals at the coupling point 303, modulates the intensity of the optical signal received from the optical transmitter 10, and modulates the intensity of the optical signal. (Hereinafter referred to as “intensity modulated optical signal”). At this time, by applying the LO signal to the hot electrode 310, the intensity modulation component is converted from the frequency of the IF signal (hereinafter referred to as “IF frequency”) to the RF frequency.
- IF frequency the frequency of the IF signal
- the optical frequency conversion unit 202 determines that, in the Y branch 304, the intensity-modulated optical signal is affected by the same effect as that of the 3 dB coupler, and the effect of applying the LO signal to the first and second waveguides. Accordingly, the intensity modulated component is in phase with the intensity modulated component of the intensity modulated optical signal (hereinafter referred to as “first optical signal”) 340, and the intensity modulated component is in phase with the intensity modulated component of the intensity modulated optical signal.
- An optical signal (hereinafter, referred to as a “second optical signal”) 341 is split into a first optical signal 340, which passes through the third waveguide, and is output to the balanced photoelectric conversion unit 203 via the optical fiber 210. Then, the second optical signal 341 passes through the fourth waveguide, and is output to the balanced photoelectric conversion unit 203 via the optical fiber 211.
- the balanced photoelectric conversion unit 203 is composed of an optical fiber 210 and an optical fiber conversion unit 202.
- the received first and second optical signals are respectively converted into electrical signals, and an RF signal is generated from the two electrical signals that have been converted.
- the electric signals obtained by electrically converting the first and second optical signals are referred to as a first RF signal and a second RF signal, respectively.
- the balanced photoelectric conversion unit 203 includes a first photodiode. (Hereinafter referred to as a “first PD”) 350, a second photodiode (hereinafter referred to as a “second PD”) 351, a power supply voltage section 353, and a capacitor 354.
- the first PD and the second PD are connected in series at a connection section 352, the other end of the first PD is grounded, and the other end of the second PD is connected to a power supply voltage section 353.
- the first PD 350 When the first PD 350 receives the first optical signal 340 from the optical frequency converter 202 via the optical fiber 210, the first PD 350 electrically converts the received first optical signal 341 to generate a first RF signal, and generates a second RF signal.
- the second optical signal 341 When the second optical signal 341 is received from the optical frequency conversion unit 202 via the optical fiber 211, the received second optical signal 341 is electrically converted to generate a second RF signal.
- connection section 352 the first RF signal and the second RF signal are added in phase, and an RF signal is generated. This is because the first RF signal generated by the first PD 350 is output in the direction of the power supply voltage unit 353, so that the phase is inverted. That is, the second PD 351 has the same phase as the second RF signal generated by the second PD 351.
- the phases of the noise components included in the first and second optical signals received by the balanced photoelectric conversion unit 203 are in phase, the first PD 350 and the second PD 351, The phases of the respective noise components output from are in an opposite phase relationship. Therefore, the noise components in the connection unit 352 are canceled each other.
- the balanced photoelectric conversion unit 203 outputs the RF signal generated by the connection unit 352 to the transmission unit 204 via the capacitor 354.
- Transmitting section 204 has antenna 220, receives an RF signal from balanced photoelectric conversion section 203, and transmits the received RF signal to mobile phone 40 via antenna 220.
- the electro-optical conversion unit 102 of the optical transmission device 10 Upon receiving an IF signal to be transmitted from the IF signal input unit 101, the electro-optical conversion unit 102 of the optical transmission device 10 optically converts the received IF signal to generate an optical signal, and transmits the generated optical signal to an optical receiver. Output to the device 20 via the optical fiber 30.
- the optical frequency converter 202 of the optical receiver 20 is connected to the optical transmitter 1 via the optical fiber 30.
- An optical signal is received from the first optical signal, the received optical signal is intensity-modulated, an intensity-modulated optical signal is generated, and a first optical signal and a second optical signal are generated from the generated intensity-modulated optical signal.
- the balanced optical-to-electrical converter 203 converts the received first and second optical signals.
- the first and second RF signals are respectively converted to generate first and second RF signals.
- the balanced photoelectric conversion unit 203 generates an RF signal by adding the first RF signal and the second RF signal in the same phase at the connection unit 352, and outputs the generated RF signal to the transmission unit 204. .
- transmitting unit 204 Upon receiving the RF signal from balance-type photoelectric conversion unit 203, transmitting unit 204 transmits the received RF signal to mobile phone 40 via antenna 220.
- the RF signals which are the intensity modulation components of the two optical signals, are added to each other, and the noise components are canceled each other, so that high-quality optical transmission can be realized.
- the optical transmitter 10 can generate an RF signal in which a noise component has been canceled by using the optical frequency converter 202 and the parallax photoelectric converter 203.
- the delay time is adjusted between the optical transmitting device and the optical receiving device so that the two optical signals transmitted via the individual optical fibers match at the optical phase level.
- the adjustment of the delay time can be easily performed by integration or the like in which the adjustment of the delay time is performed only on the optical receiving device 20 side.
- the configuration is such that an electric field is generated in both the first and second wave paths, but the present invention is not limited to this.
- the configuration may be such that an electric field is generated only in one of the first and second waveguides.
- the force using one hot electrode is not limited to this. It may be a two-electrode type having two hot electrodes. The operation in the case of the two-electrode type is the same as that in the case of one hot electrode described above, and the intensity modulation component of the intensity modulation light signal generated by the intensity modulation is the RF frequency.
- optical frequency conversion unit 202 is a chirp-type Matsuhender-type external modulator, it may be a zero-chirp-type Mach-Zehnder-type external modulator.
- the operation of the zero-chirp Mach-Zehnder external modulator is the same as the operation of the chirp Mach-Zehnder external modulator.
- the other end of the first PD is grounded, and the other end of the second PD is connected to the power supply voltage unit 353.
- the power is not limited to this.
- the other end of the first PD may be connected to the power supply voltage unit 353, and the other end of the second PD may be grounded. In this case, an RF signal with noise components canceled can be generated.
- the Y-branch is used to split the optical signal received from the optical transmitter 10
- a device that can split the received optical power in half instead of the Y-branch may be used.
- a device that can split the received optical power in half instead of the Y-split may be used.
- an example of an alternative device to the Y branch is a 3 dB coupler.
- the optical transmission system 1A includes an optical transmitter 10A, an optical receiver 20A, and an optical fiber 30A.
- the optical transmitting device 10A and the optical receiving device 20A are connected by an optical fiber 30A and are connected.
- the optical transmitting device 10A converts the IF signal into an optical signal, further changes the polarization state of the converted optical signal to a non-polarized state, and converts the non-polarized optical signal into an optical receiving device 20A via an optical fiber 30A.
- Send to The optical receiver 20A receives the non-polarized optical signal from the optical transmitter 10A via the optical fiber 30A, converts the IF signal into an RF signal using the received non-polarized optical signal, Transmits the converted RF signal to mobile phone 40A.
- the optical transmission device 10A includes an IF signal input unit 101A, an electro-optic conversion unit 102A, and a polarization scrambler 103A.
- the electro-optic conversion unit 102A and the polarization scrambler 103A are They are connected by an optical fiber 110A.
- the IF signal input unit 101A receives an input of an IF signal to be transmitted to the optical receiving device 20A, and outputs the received IF signal to the electro-optical conversion unit 102A.
- Electro-optical converter 102A is, specifically, a semiconductor laser module. Upon receiving an IF signal from the IF signal input unit 101A, the electro-optical converter 102A converts the received IF signal into an optical signal having a linear polarization state. A signal is generated, and the generated optical signal is output to the polarization scrambler 103A via the optical fiber 110A.
- the polarization scrambler 103A receives an optical signal from the electro-optical converter 102A via the optical fiber 11OA, adjusts the received optical signal to a non-polarized state in which the polarization state is random, and adjusts to a non-polarized state. an optical signal through the optical fiber 30A and outputs it to the optical receiver 2 OA.
- the polarization scrambler 103A will be described below with reference to “Communication Engineering 1” by Hatori et al. (Published by Corona Co., Ltd.).
- the polarization scrambler 103A is a polarization modulator, and simultaneously applies two orthogonal polarizations, that is, a TE polarization and a TM polarization, at an input point of incident light that is linear polarization.
- the modulation is performed by changing the phase difference between the two polarized waves by the voltage.
- the polarization state of the incident light is set to linear polarization, and the light is incident at an angle of 45 degrees with respect to the axis of the waveguide section of the polarization scrambler.
- the phase difference between the two polarized lights seen at the output end is 0 ° and 45 depending on the magnitude of the applied voltage. ⁇ 90. , 135 °, 180. , 135 ° ⁇ 90. , 45. , 0 °.
- the polarization state of the output light of the polarization scrambler 103A is linearly polarized, elliptically polarized, circularly polarized, elliptically polarized, circularly polarized, and linearly polarized (which is orthogonal to the first linearly polarized light). Changes in the reverse order.
- FIG. 6 (a) is a diagram illustrating a case where the phase difference between the two polarizations viewed at the output terminal is 0 degree, that is, a case where the polarization state of the output light of the polarization scrambler 103A is linear polarization.
- FIG. 6 (b) is a diagram illustrating a case where the phase difference between the two polarizations viewed at the output end is 90 degrees, that is, a case where the polarization state of the output light of the polarization scrambler 103A is circular polarization.
- FIG. 6 is a diagram described in the cited document.
- the polarization scrambler 103A repeats this change 5 ⁇ 10 9 times per second, whereby the polarization state can be changed to a random state, that is, a non-polarization state.
- the optical receiver 20A also includes a LO signal input unit 201A, an optical frequency conversion unit 202A, a parallax photoelectric conversion unit 203A, and a transmission unit 204A having an antenna 220A.
- the converter 202A and the balanced photoelectric converter 203A are connected by optical fibers 210A and 211A.
- the LO signal input unit 201A, the balanced photoelectric conversion unit 203A, and the transmission unit 204A are the L signal input unit 201, the balanced photoelectric conversion unit 203, and the transmission unit 204 shown in the first embodiment. The description is omitted because it is the same.
- the optical frequency converter 202A is, specifically, a Mach-Zehnder type external modulator of a chirp type, and has the same configuration as the optical frequency converter 202 shown in the first embodiment.
- the optical frequency converter 202A receives an optical signal adjusted to a non-polarized state from the optical transmitter 10A via the optical fiber 30A.
- the optical frequency conversion unit 202A uses the LO signal received from the LO signal
- the received optical signal adjusted to the non-polarized state is intensity-modulated to generate an intensity-modulated optical signal, and a first optical signal and a second optical signal are generated from the generated intensity-modulated optical signal.
- the optical frequency converter 202A outputs the generated first optical signal to the balanced optical-electrical converter 203A via the optical fiber 210A, and outputs the generated second optical signal via the optical fiber 211 to the balanced optical-electrical converter. Output to section 203A.
- the electro-optical conversion unit 102A of the optical transmission device 10A Upon receiving the IF signal to be transmitted from the IF signal input unit 101A, the electro-optical conversion unit 102A of the optical transmission device 10A optically converts the received IF signal to generate an optical signal, and converts the generated optical signal into a polarization scrambled signal. Output to Bra 103A.
- the polarization scrambler 103A adjusts the polarization state of the received optical signal to a non-polarized state, and sends the optical signal adjusted to the non-polarized state to the optical receiver 20A. Output via optical fiber 30A.
- the optical frequency converter 202A of the optical receiver 20A receives the optical signal adjusted to the non-polarized state from the optical transmitter 10A via the optical fiber 30A, and modulates the intensity of the received optical signal adjusted to the non-polarized state. Generate an intensity-modulated optical signal, and generate a The first optical signal and the second optical signal are generated, and the generated first and second optical signals are output to the balanced photoelectric conversion unit 203A via the optical fiber 210A and the optical fiber 211A, respectively.
- the balanced photoelectric conversion unit 203A converts the received first and second optical signals into electrical signals, respectively, and converts the first and second optical signals into first and second optical signals.
- a second RF signal is generated, the generated first RF signal is inverted in phase, added to the second RF signal, an RF signal is generated, and the generated RF signal is output to the transmitting unit 204A.
- transmitting section 204A receives the RF signal from balanced photoelectric conversion section 203A, transmitting section 204A transmits the received RF signal to mobile phone 40A via antenna 220A.
- the inputtable photoelectric power depends on the polarization plane of the optical signal. Therefore, the coupling efficiency indicating the ratio of the input optical signal greatly changes depending on the polarization state of the input optical signal. / 2 can be combined. This is because, when an optical signal is incident, if the plane of polarization is orthogonal to the plane of polarization incident on the external modulator, the incident power becomes “0”, and the plane of polarization incident on the external modulator is In the case of the same, all the optical power of the optical signal is incident.
- the optical signal output from the optical transmission device 10A is linearly polarized, and the coupling efficiency may be significantly deteriorated depending on the installation state of the optical fiber 30A. Therefore, by adjusting the polarization state of the optical signal to the non-polarized state, stable improvement of the coupling efficiency can be realized.
- the optical transmission system 1A it is only necessary to provide one optical fiber between the optical transmitting device 10A and the optical receiving device 2OA, so the construction cost is lower than that of the conventional optical transmission system. Become cheap. Further, in the optical transmission device 10A, an RF signal in which a noise component has been canceled can be generated using the optical frequency conversion unit 202A and the balance-type photoelectric conversion unit 203A.
- a delay time is set between an optical transmitting device and an optical receiving device so that two optical signals transmitted through separate optical fibers coincide at an optical phase level.
- the adjustment of the delay time is facilitated by integrating the delay time only by adjusting the delay time on the side of the optical receiving device 20A.
- the coupling efficiency can be improved by adjusting the polarization state of the optical signal output from the optical transmitter 10A to the optical receiver 20A to a non-polarized state and outputting the signal.
- the optical transmission system 1B includes an optical transmitting device 10B, an optical receiving device 20B, and an optical fiber 30B.
- the optical transmitter 10B and the optical receiver 20B are connected by an optical fiber 30B.
- the optical transmitter 10B converts the IF signal into an optical signal, and transmits the converted optical signal to the optical receiver 20B via the optical fiber 30B.
- the optical receiver 20B receives an optical signal from the optical transmitter 10B via the optical fiber 30B, converts the IF signal into an RF signal using the received optical signal, and transmits the converted RF signal to the mobile phone 40B. Send.
- the optical transmission device 10B includes an IF signal input unit 101B and an electro-optical conversion unit 102B.
- the IF signal input unit 101B and the electro-optical conversion unit 102B are the same as the IF signal input unit 101 and the electro-optical conversion unit 102 shown in the first embodiment, and thus description thereof will be omitted.
- the optical receiving device 20B includes an LO signal input unit 201B, an optical frequency conversion unit 202B, a Norrance type photoelectric conversion unit 203B, a transmission unit 204B having an antenna 220B, and a polarization control unit 205B.
- the optical frequency converter 202B and the parallax photoelectric converter 203B are connected by optical fibers 210B and 21 IB, and the optical frequency converter 202B and the polarization controller 205 They are connected by a fiber 212B.
- An example of the polarization maintaining fin 212B is a panda optical fiber.
- the LO signal input unit 201B, the balanced photoelectric conversion unit 203B, and the transmission unit 204B are the same as the LO signal input unit 201, the balanced photoelectric conversion unit 203, and the transmission unit 204 shown in the first embodiment. Therefore, the description is omitted.
- an external modulator such as the optical frequency converter 202B
- the inputtable photoelectric power depends on the polarization plane of the optical signal. Note that the optical frequency conversion unit 2′02B shown here receives an optical signal whose polarization state is horizontal polarization, which will be described below.
- the polarization control unit 205B separates the received optical signal into a horizontal optical signal whose polarization state is horizontal polarization and a vertical optical signal whose polarization state is vertical polarization. • Generates an optical signal whose polarization state is only horizontal polarization (hereinafter referred to as “multiplexed optical signal”) from the optical signal.
- the polarization control unit 205B includes a collimator lens 401B, 402B, 403B, a polarization separation element 404B, and a wavelength for rotating the polarization state of the optical signal from vertical polarization to horizontal polarization as shown in FIG.
- the plate 405B and the polarization maintaining coupler 406B are configured.
- the collimator lens 401B is connected to the optical fiber 30B.
- the polarization maintaining coupler 406B is connected to the polarization maintaining fiber 212B.
- the polarization separation element 404B is, for example, a rutile crystal.
- the polarization control unit 205B receives an optical signal from the optical transmission device 10B via the optical fiber 30 by the collimator lens 401B, and separates the received optical signal into a vertical optical signal and a horizontal optical signal by the polarization separation element 404B. To separate.
- the separated vertical optical signal After passing through the polarization splitter 404B, the separated vertical optical signal is rotated by the wave plate 405B so that the polarization state becomes horizontal polarization, and the rotated vertical optical signal (hereinafter, referred to as the ⁇ rotated optical signal Is input to the polarization maintaining coupler 406B via the collimator lens 402B.
- the separated horizontal optical signal passes through the polarization splitter 404B, and then enters the polarization maintaining coupler 406B via the collimator lens 403B.
- the polarization-maintaining power blur 406B multiplexes the rotation optical signal and the horizontal optical signal to generate a multiplexed optical signal, and converts the generated multiplexed optical signal through the polarization-maintaining fiber 212B into the optical frequency converter 20. Output to 2B.
- the optical frequency conversion unit 202B is, specifically, a Mach-Zehnder type external modulator of a chirp type, and has a configuration similar to that of the optical frequency conversion unit 202 shown in the first embodiment.
- the optical frequency converter 202B is transmitted from the polarization controller 205B via the polarization maintaining fiber 212B. Receive the multiplexed optical signal.
- the optical frequency conversion unit 202B uses the LO signal received from the LO signal input unit 201B to generate a polarization control unit 205B.
- the received optical signal is intensity-modulated to generate an intensity-modulated optical signal, and a first optical signal and a second optical signal are generated from the generated intensity-modulated optical signal.
- the optical frequency conversion unit 202B outputs the generated first optical signal to the balance type photoelectric conversion unit 203B via the optical fiber 210B, and outputs the generated second optical signal via the optical fiber 211B. Output to electrical converter 203B.
- the electro-optical converter 102B of the optical transmitter 10B Upon receiving the IF signal to be transmitted from the IF signal input unit 101B, the electro-optical converter 102B of the optical transmitter 10B optically converts the received IF signal to generate an optical signal, and converts the generated optical signal into an optical receiver. Output to 20B via optical fiber 30B.
- the polarization control unit 205B of the optical receiver 20B receives the optical signal from the optical transmitter 10B via the optical fiber 30B and adjusts the polarization state of the received optical signal to horizontal polarization, that is, generates a multiplexed optical signal. Then, the generated multiplexed optical signal is output to the optical frequency conversion unit 202B.
- the optical frequency converter 202B receives the multiplexed optical signal from the polarization controller 205B, generates an intensity-modulated optical signal by intensity-modulating the received multiplexed optical signal, and generates a first optical signal from the generated intensity-modulated optical signal. A second optical signal is generated, and the generated first and second optical signals are output to the balanced photoelectric conversion unit 203B via the optical fiber 21OB and the optical fiber 211B, respectively.
- the balanced photoelectric conversion unit 203B when receiving the first and second optical signals from the optical frequency conversion unit 202B, the balanced photoelectric conversion unit 203B performs electrical conversion on the received first and second optical signals, respectively, and outputs the first and second optical signals.
- a second RF signal is generated, the generated first RF signal is inverted in phase, added to the second RF signal to generate an RF signal, and the generated RF signal is output to the transmitting unit 204B.
- the transmission unit 204B Upon receiving the RF signal from the balanced photoelectric conversion unit 203B, transmits the received RF signal to the mobile phone 40B via the antenna 220B.
- the polarization state of the optical signal is changed so that the optical frequency conversion unit 202B can receive the polarization state. Can be adjusted.
- the coupling efficiency in the optical frequency conversion unit 202B can be increased, that is, the coupling state of the optical signal can be increased.
- the optical frequency conversion unit 202B receives an optical signal whose polarization state is horizontal polarization, but the optical frequency conversion unit 202B receives an optical signal whose polarization state is vertical polarization. May be received.
- the configuration may be such that the LO signal is input on the optical transmission device side.
- the optical transmission system 1C at this time will be described below.
- the optical transmission system 1C also includes an optical transmitting device 10C, an optical receiving device 20C, and an optical fiber 30C.
- the optical transmitter 10C and the optical receiver 20C are connected by an optical fiber 30C.
- the optical transmitter 10C converts the IF signal into an IF optical signal by optical conversion, and converts the LO signal into an LO optical signal by optical conversion.
- the optical transmitting device 10C multiplexes the IF optical signal and the LO optical signal, and transmits the multiplexed optical signal to the optical receiving device 20C via the optical fiber 30C.
- the optical receiver 20C receives the multiplexed optical signal from the optical transmitter 10C via the optical fiber 30C, generates an RF signal from the received multiplexed optical signal, and converts the generated RF signal into a mobile phone. Send to 40C.
- the optical transmitting apparatus 10C includes an IF signal input section 101C, a first electro-optical conversion section 105C, an LO signal input section 106C, a second electro-optical conversion section 107C, and an optical multiplexing section 108C. It is composed of The first electro-optical converter 105C and the optical multiplexing unit 108C are connected by an optical fiber 111C, and the second electro-optical converter 107C and the optical multiplexing unit 108C are connected by an optical fiber 112C.
- the IF signal input section 101C receives an input of an IF signal to be transmitted to the optical receiver 20C.
- the received IF signal is output to the first electro-optical converter 105C.
- the first electro-optical conversion unit 105C is, specifically, a semiconductor laser module. Upon receiving an IF signal from the IF signal input unit 101C, the first electro-optical conversion unit 105C optically converts the received IF signal to generate an IF optical signal. The generated IF optical signal is output to the optical multiplexing unit 108C via the optical fiber 111C.
- the LO signal input unit 106C receives the input of the L ⁇ signal, and outputs the received LO signal to the second electrical / optical conversion unit 107C.
- the second electro-optical converter 107C is, specifically, a semiconductor laser module.
- the second electro-optical converter 107C uses the received LO signal and light having a different wavelength from the IF optical signal.
- the optical signal is then optically converted to generate an LO optical signal, and the generated LO optical signal is output to the optical multiplexing unit 108C via the optical fiber 112C.
- the optical multiplexing unit 108C is specifically an optical multiplexer, receives an IF optical signal from the first electro-optical conversion unit 105C via the optical filter 111C, and further receives an optical fiber from the second electro-optical conversion unit 107C.
- the LO optical signal is received via the USB 112C.
- the received IF optical signal and LO optical signal are multiplexed to generate a multiplexed optical signal, and the generated multiplexed optical signal is output to the optical receiver 20C via the optical fiber 30C.
- the optical receiving device 20C includes an optical frequency conversion unit 202C, a balanced photoelectric conversion unit 203C, a transmission unit 204C having an antenna 220C, a light separation unit 206C, and a photoelectric conversion unit 207C.
- the optical frequency converter 202C and the balanced photoelectric converter 203C are connected by optical fibers 210C and 211C, and the optical separator 206C and the photoelectric converter 207C are connected by an optical fiber 213C.
- the separation unit 206C and the optical frequency conversion unit 202C are connected by an optical fiber 214C.
- the nonce photoelectric conversion unit 203C and the transmission unit 204C are the same as the balance photoelectric conversion unit 203 and the transmission unit 204 shown in the first embodiment, and thus description thereof is omitted.
- the optical demultiplexing unit 206 is, specifically, an optical demultiplexer, and upon receiving a multiplexed optical signal from the optical transmission device 10C via the optical fiber 30C, separates the received multiplexed optical signal to form an IF optical signal. And ⁇ Acquire the LO light signal.
- the optical separation unit 206C outputs the obtained IF optical signal to the optical frequency conversion unit 202C via the optical fiber 214C, and outputs the obtained LO optical signal to the photoelectric conversion unit 207C via the optical fiber 213C.
- the photoelectric conversion unit 207C is, specifically, a photodiode.
- the photoelectric conversion unit 207C receives the LO optical signal from the optical separation unit 206C via the optical fiber 213C, and performs electrical conversion on the received LO optical signal to generate an L ⁇ signal.
- the photoelectric conversion unit 207C outputs the generated LO signal to the optical frequency conversion unit 202C.
- the optical frequency converter 202C is, specifically, a Mach-Zehnder type external modulator of a chirp type, and has the same configuration as the optical frequency converter 202 shown in the first embodiment.
- the optical frequency converter 202C receives the IF optical signal from the optical separator 206C via the optical fiber 214C, and receives the LO signal from the photoelectric converter 207C.
- the optical frequency conversion unit 202C receives the optical frequency conversion unit 202C from the optical separation unit 206C using the LO signal received from the photoelectric conversion unit 207C, similarly to the optical frequency conversion unit 202 described in the first embodiment.
- An intensity-modulated optical signal is generated by intensity-modulating the IF optical signal, and a first optical signal and a second optical signal are generated from the generated intensity-modulated optical signal.
- the optical frequency converter 202B outputs the generated first optical signal to the balanced optical-electrical converter 203C via the optical fiber 210C, and outputs the generated second optical signal via the optical fiber 211C to the balanced optical-electrical converter. Output to section 203C.
- the first electro-optical converter 105C of the optical transmitter 10C Upon receiving the IF signal to be transmitted from the IF signal input unit 101C, the first electro-optical converter 105C of the optical transmitter 10C optically converts the received IF signal to generate an IF optical signal, and generates the generated IF optical signal. Is output to the optical multiplexing unit 108C.
- the second electro-optical conversion unit 107C optically converts the received L ⁇ signal to generate an L ⁇ optical signal, and transmits the generated LO optical signal to the optical multiplexing unit 108C. Output.
- the optical multiplexing unit 108C multiplexes the received IF optical signal and the LO optical signal to multiplex them. An optical signal is generated, and the generated multiplexed optical signal is output to the optical receiver 20C via the optical fiber 30C.
- the optical separation unit 206C of the optical receiving device 20C receives the multiplexed optical signal from the optical transmitting device 10C via the optical fiber 30C, separates the received multiplexed optical signal, and obtains the IF optical signal and the LO optical signal.
- the optical separation unit 206C outputs the obtained LO signal to the photoelectric conversion unit 207C, and outputs the obtained IF signal to the optical frequency conversion unit 202C.
- the photoelectric conversion unit 207C Upon receiving the LO optical signal from the optical separation unit 206C, the photoelectric conversion unit 207C The O optical signal is electrically converted to generate an LO signal, and the generated L ⁇ signal is output to the optical frequency conversion unit 202C.
- the optical frequency conversion unit 202C intensity-modulates the IF optical signal using the LO signal received from the photoelectric conversion unit 207C to generate an intensity-modulated optical signal.
- a first optical signal and a second optical signal are generated from the generated intensity-modulated optical signal, and the generated first and second optical signals are respectively transmitted to a balance-type photoelectric converter via an optical fiber 210C and an optical fiber 211C. Output to 203C.
- the balanced photoelectric conversion unit 203C converts the received first and second optical signals into electrical signals, respectively, to perform the first and second optical signals.
- a second RF signal is generated, the generated first RF signal is inverted in phase, added to the second RF signal to generate an RF signal, and the generated RF signal is output to the transmitting unit 204C.
- transmitting unit 204C transmits the received RF signal to mobile phone 40C via antenna 220C.
- the optical transmission device 10C of the optical transmission system 1C has a configuration in which the IF signal and the LO signal are simultaneously optically transmitted, so that maintenance of the entire system can be easily performed.
- the RF signal is transmitted from the optical receiver to the mobile phone, but the present invention is not limited to this.
- Optical receivers can transmit RF signals to computer equipment that can communicate, such as personal computers, or they can transmit RF signals to broadcast receivers such as television tuners.
- the electro-optical converter is a semiconductor laser module.
- the electro-optical converter may be a combination of a semiconductor laser module and a Matsuhazender type external modulator.
- the first and second electro-optical converters shown in (1) above may be a combination of a semiconductor laser module and a Mach-Zehnder external modulator.
- an optical signal is transmitted from an optical transmitter to an optical receiver, a process of canceling a noise component mixed during transmission is performed, and an output electric signal is output.
- the optical receiving apparatus and the optical transmitting apparatus are coupled by one optical fiber, and an optical signal before intensity modulation is transmitted through the optical fiber.
- a first processing unit that intensity-modulates the received optical signal and converts the intensity-modulated components into two optical signals having phases opposite to each other, and a first and a second unit that transmits optical signals whose intensity-modulated components have phases opposite to each other. It is characterized by comprising: two transmission optical fibers; and a second processing unit that converts each of the two optical signals into an electric signal at the transmission end, and inverts and amplifies to generate an output electric signal.
- the optical receiver modulates the intensity of the received optical signal to generate two optical signals in which the intensity modulation components are out of phase with each other, and combines the generated two optical signals. Each of them can be converted into an electric signal and inverted and amplified to generate an output electric signal.
- the optical receiving device does not need to receive two optical signals in which the intensity modulation components are out of phase with each other. That is, the optical transmitting device and the optical receiving device need not be connected to each other. There is no need to connect with two optical fibers, and construction costs are reduced.
- the two optical signals whose intensity modulation components are out of phase with each other are converted into electric signals, and one of the two converted electric signals is inverted, the electric signals of the two become in-phase and the noise components of each other become The phase can be reversed. As a result, when generating the output electric signal, the phase of the noise component is canceled, and a high-quality output electric signal can be generated.
- the optical transmission device receives an electric signal, optically converts the received electric signal to generate an optical signal, and outputs the generated optical signal to the optical receiving device via the optical fiber. Even if it has a part.
- the optical transmission device of the optical transmission system can transmit an optical signal to the optical reception device via one optical fiber. This eliminates the need to individually output optical signals to two optical fibers as in the conventional optical transmission device.
- the first processing unit receives the optical signal via the optical fiber, and intensity-modulates the received optical signal based on the frequency of the modulated electric signal having a certain frequency, and modulates the modulated optical signal.
- a first output optical signal and a second output optical signal having mutually opposite intensity modulation components having opposite phases are generated from the generated intensity modulation unit and the generated modulated optical signal, and the generated first and second output light signals are generated.
- a light splitting unit that outputs a signal to the first and second transmission optical fibers, respectively, wherein the second processing unit receives the first and second signals received via the first and second transmission optical fibers.
- An inverted amplifier may be configured to invert the phase of the generated second electric signal, add the inverted second electric signal to the first electric signal, and generate an output electric signal.
- the optical receiving device of the optical transmission system generates a modulated optical signal by intensity-modulating the received optical signal in the intensity modulator, and the first optical signal is generated from the modulated optical signal generated in the optical splitter. And a second output optical signal.
- the photoelectric conversion unit converts the first and second output optical signals into electric signals to generate first and second output electric signals.
- An output electric signal can be generated from the first and second output electric signals. This makes it possible to generate an output electric signal in which the noise component has been canceled.
- the first processing unit may be configured by a Mach-Zehnder type external modulator
- the second processing unit may be configured by a Parance type photoelectric converter
- the optical receiver of the optical transmission system can be composed of a Mach-Zehnder external modulator and a balanced photoelectric converter.
- the electric signal received by the output processing unit is an intermediate frequency signal having a frequency different from the frequency of a radio frequency signal
- the modulated electric signal is a local transmission signal
- the intensity modulation unit is Based on the frequency of the local transmission signal
- the received optical signal is intensity-modulated to generate a modulated optical signal whose intensity-modulated component is the frequency of the radio frequency signal
- the second output optical signal is respectively converted into electric signals to generate first and second electric signals having a component of a radio frequency signal
- the inverting amplifier changes the phase of the generated second electric signal to the opposite phase.
- the radio frequency signal may be generated by adding the radio frequency signal to the first electric signal.
- the optical receiver of the optical transmission system can generate a radio frequency signal as an output electric signal by performing intensity modulation on the basis of the frequency of the local transmission signal.
- the optical receiver can be used as a device that outputs a radio frequency signal.
- the output processing unit receives the electric signal, optically converts the received electric signal to generate an optical signal, and outputs the generated optical signal to a third transmission optical fiber;
- a polarization scrambler that receives the optical signal through a transmission optical fiber, randomly changes a polarization state of the received optical signal, and outputs the optical signal to the optical receiver via the optical fiber. I'll be prepared.
- the optical transmission device of the optical transmission system can output an optical signal whose polarization state changes randomly to the optical reception device.
- the first processing unit may receive an optical signal whose polarization state changes randomly from the optical transmission device via the optical fiber.
- the optical receiving device of the optical transmission system can receive an optical signal that changes randomly in the polarization state S from the optical transmitting device.
- the optical receiving device can receive an optical signal with stable coupling efficiency.
- the optical receiving device further receives an optical signal from the optical transmitting device via the optical fiber, and uses the polarization component of the received optical signal as a signal when the first processing unit receives the optical signal.
- a polarization control unit that controls a polarization state of the optical signal so as to match the polarization component of the optical signal, and outputs an optical signal whose polarization state is controlled to the first processing unit, wherein the first processing unit
- an optical signal whose polarization state is controlled may be received from the polarization control unit.
- the optical receiver of the optical transmission system can perform control so that the polarization state of the received optical signal and the polarization state when the first processing unit receives the optical signal are matched.
- the first processing unit can receive the optical signal with stable coupling efficiency.
- the polarization component of the optical signal has a first polarization and a second polarization
- the polarization component when the first processing unit receives the optical signal is a first polarization
- the polarization control unit includes: a separation unit that separates the optical signal into a first polarization signal having a first polarization and a second polarization signal having a second polarization; A rotation unit configured to rotate the second polarization so that a polarization state of the signal becomes the first polarization and generate a third polarization signal having the first polarization; and the first polarization signal.
- a multiplexing unit that multiplexes the third polarization signal to generate a multiplexed optical signal composed of only the first polarization, and wherein the optical signal whose polarization state is controlled includes the composite wave. It may be.
- the polarization control unit of the optical receiver in the optical transmission system can generate a multiplexed optical signal in which the polarization component is only the first polarization, and the first processing unit is capable of generating the multiplexed optical signal power.
- the first and second generation optical signals can be generated.
- the first processing unit can receive the optical signal whose polarization state is controlled with stable coupling efficiency.
- An output processing unit that receives the electrical signal, optically converts the received electrical signal to generate a transmission optical signal, and outputs the generated transmission optical signal to a third transmission optical fiber; Generated a modulated optical signal by optically converting a modulated electrical signal having a certain frequency, A conversion processing unit for outputting a modulated optical signal to a fourth transmission optical fiber; a transmission optical signal received through the third transmission optical fiber; and a fourth transmission optical fiber receiving the modulated optical signal.
- the optical transmission device of the optical transmission system can transmit the transmission optical signal and the modulated optical signal to the optical reception device via one optical fiber.
- the electric signal and the modulated electric signal can be managed by the optical receiver, so that maintenance is simplified.
- the optical receiving device further receives a multiplexed optical signal from the optical transmitting device via the optical fiber, separates the received multiplexed optical signal into the transmission optical signal and the modulated optical signal, and separates the multiplexed optical signal.
- a first photoelectric conversion unit that converts the modulated optical signal into an electric signal to generate a modulated electric signal, and outputs the generated modulated electric signal to the first processing unit;
- the signal is the transmission optical signal
- the first processing unit modulates the intensity of the transmission optical signal received from the first photoelectric conversion unit based on the frequency of the modulated electric signal.
- An intensity modulation section for generating the To generate a first output optical signal and a second output optical signal whose intensity modulation components have opposite phases, and generate the first and second output optical signals respectively in the first and second transmission optical fibers.
- the second processing unit converts the first and second output optical signals received via the first and second transmission optical fibers into first and second output optical signals, respectively.
- a second photoelectric conversion unit that generates an electrical signal, and an inverting amplifier that inverts the phase of the generated second electrical signal and adds the inverted second electrical signal to the first electrical signal to generate an output electrical signal. Is also good.
- the optical receiving device of the optical transmission system can receive the multiplexed optical signal received from the optical transmitting device and generate an output electric signal using the received multiplexed optical signal. Therefore, maintenance such as management of the optical receiver can be simplified.
- the electric signal received by the output processing unit is an intermediate frequency signal having a frequency different from the frequency of a radio frequency signal
- the modulated electric signal is a local oscillation signal
- the intensity modulation unit is Based on the frequency of the transmitted signal
- the received transmitted optical signal is The intensity modulation is performed to generate a modulated optical signal whose intensity modulation component is the frequency of the radio frequency signal
- the second photoelectric conversion unit converts the received first and second output optical signals into electrical signals, respectively, and A first and a second electric signal having a signal component are generated, and the inverting amplification section reverses the phase of the generated second electric signal and adds the inverted second electric signal to the first electric signal to generate a radio frequency signal. May be generated.
- the optical receiving device of the optical transmission system can generate a radio frequency signal as an output electric signal by performing strong modulation based on the frequency of the local oscillation signal.
- the optical receiving device can be used as a device that outputs a radio frequency signal.
- optical transmission system described above can be used business-wise, that is, repetitively and continuously, in the industry of providing information, audio, video, and the like to consumers using a communication system using optical fibers.
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- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Optical Communication System (AREA)
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
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EP04708870A EP1615357A4 (en) | 2003-02-07 | 2004-02-06 | OPTICAL TRANSMISSION SYSTEM |
US10/537,171 US7751722B2 (en) | 2003-02-07 | 2004-02-06 | Optical transmission system |
JP2005504895A JP4592588B2 (ja) | 2003-02-07 | 2004-02-06 | 光伝送システム |
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JP2003-031221 | 2003-02-07 | ||
JP2003031221 | 2003-02-07 |
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WO2004070976A1 true WO2004070976A1 (ja) | 2004-08-19 |
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PCT/JP2004/001266 WO2004070976A1 (ja) | 2003-02-07 | 2004-02-06 | 光伝送システム |
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US (1) | US7751722B2 (ja) |
EP (1) | EP1615357A4 (ja) |
JP (1) | JP4592588B2 (ja) |
KR (1) | KR100977921B1 (ja) |
CN (1) | CN1748378A (ja) |
WO (1) | WO2004070976A1 (ja) |
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KR100759271B1 (ko) | 2006-08-17 | 2007-09-17 | 한국전자통신연구원 | RoF 통신 시스템에 사용되는 광 송수신기 |
KR100770882B1 (ko) * | 2006-11-10 | 2007-10-26 | 삼성전자주식회사 | 광수신 장치 및 이를 이용한 광통신 시스템 |
GB0905820D0 (en) * | 2009-04-03 | 2009-05-20 | Bae Systems Plc | Improvements relating to signal processing |
CN102884738B (zh) * | 2011-04-20 | 2015-04-08 | 华为技术有限公司 | 基于微波光子技术的信号接收装置和信号接收方法 |
Citations (2)
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JPH07283793A (ja) * | 1994-04-11 | 1995-10-27 | Hitachi Ltd | コヒーレント光伝送方式 |
JPH10117172A (ja) * | 1996-10-11 | 1998-05-06 | Matsushita Electric Ind Co Ltd | 光伝送システム |
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CA2156430C (en) * | 1993-03-31 | 2000-03-21 | Ian Christopher Smith | Generation of optical signals with rf components |
US5410404A (en) * | 1993-11-30 | 1995-04-25 | The United States Of America As Represented By The Secretary Of The Navy | Fiber grating-based detection system for wavelength encoded fiber sensors |
DE69525159T2 (de) * | 1994-03-30 | 2002-08-22 | British Telecomm | Erzeugung von hochfrequenzmodulierter optischer strahlung |
DE19722370A1 (de) * | 1997-05-28 | 1998-12-03 | Alsthom Cge Alcatel | Empfänger für ein optisches Nachrichtenübertragungssystem und Verfahren zu dessen Betrieb |
US6459830B1 (en) * | 2000-02-08 | 2002-10-01 | Sprint Communications Company L.P. | Method and apparatus to compensate for polarization mode dispersion |
US6822743B2 (en) * | 2001-03-07 | 2004-11-23 | Paul Trinh | Integrated-optic channel monitoring |
US7200344B1 (en) | 2001-05-10 | 2007-04-03 | Fujitsu Limited | Receiver and method for a multichannel optical communication system |
JP4332616B2 (ja) * | 2002-04-23 | 2009-09-16 | 独立行政法人情報通信研究機構 | 変調された光の信号処理方法およびその装置 |
US7260330B2 (en) * | 2002-11-04 | 2007-08-21 | The Boeing Company | Optical communication system using correlation receiver |
-
2004
- 2004-02-06 JP JP2005504895A patent/JP4592588B2/ja not_active Expired - Fee Related
- 2004-02-06 WO PCT/JP2004/001266 patent/WO2004070976A1/ja active Application Filing
- 2004-02-06 KR KR1020057014404A patent/KR100977921B1/ko not_active IP Right Cessation
- 2004-02-06 CN CNA2004800037852A patent/CN1748378A/zh active Pending
- 2004-02-06 EP EP04708870A patent/EP1615357A4/en not_active Withdrawn
- 2004-02-06 US US10/537,171 patent/US7751722B2/en not_active Expired - Fee Related
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH07283793A (ja) * | 1994-04-11 | 1995-10-27 | Hitachi Ltd | コヒーレント光伝送方式 |
JPH10117172A (ja) * | 1996-10-11 | 1998-05-06 | Matsushita Electric Ind Co Ltd | 光伝送システム |
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Title |
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See also references of EP1615357A4 * |
Also Published As
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JPWO2004070976A1 (ja) | 2006-06-01 |
US7751722B2 (en) | 2010-07-06 |
KR100977921B1 (ko) | 2010-08-24 |
KR20050098297A (ko) | 2005-10-11 |
CN1748378A (zh) | 2006-03-15 |
JP4592588B2 (ja) | 2010-12-01 |
EP1615357A4 (en) | 2009-03-04 |
EP1615357A1 (en) | 2006-01-11 |
US20060045535A1 (en) | 2006-03-02 |
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