WO2012086283A1 - Modulateur, émetteur et système de communication - Google Patents

Modulateur, émetteur et système de communication Download PDF

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Publication number
WO2012086283A1
WO2012086283A1 PCT/JP2011/072196 JP2011072196W WO2012086283A1 WO 2012086283 A1 WO2012086283 A1 WO 2012086283A1 JP 2011072196 W JP2011072196 W JP 2011072196W WO 2012086283 A1 WO2012086283 A1 WO 2012086283A1
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Prior art keywords
light
modulation means
moth
signal
eye structure
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PCT/JP2011/072196
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English (en)
Japanese (ja)
Inventor
顕次 柴田
功 今岡
上山　智
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株式会社豊田自動織機
学校法人 名城大学
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Publication of WO2012086283A1 publication Critical patent/WO2012086283A1/fr

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    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/03—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on ceramics or electro-optical crystals, e.g. exhibiting Pockels effect or Kerr effect
    • G02F1/0305—Constructional arrangements
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/02—Details
    • G01J3/0205—Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/02—Details
    • G01J3/0205—Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows
    • G01J3/0232—Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows using shutters
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/12—Generating the spectrum; Monochromators
    • G01J3/18—Generating the spectrum; Monochromators using diffraction elements, e.g. grating
    • G01J3/1895—Generating the spectrum; Monochromators using diffraction elements, e.g. grating using fiber Bragg gratings or gratings integrated in a waveguide
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/18—Diffraction gratings
    • G02B5/1809—Diffraction gratings with pitch less than or comparable to the wavelength
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B6/12007—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind forming wavelength selective elements, e.g. multiplexer, demultiplexer
    • G02B6/12009—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind forming wavelength selective elements, e.g. multiplexer, demultiplexer comprising arrayed waveguide grating [AWG] devices, i.e. with a phased array of waveguides
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/29—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the position or the direction of light beams, i.e. deflection
    • G02F1/31—Digital deflection, i.e. optical switching
    • G02F1/315—Digital deflection, i.e. optical switching based on the use of controlled internal reflection
    • 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
    • H04B10/501—Structural aspects
    • H04B10/503—Laser transmitters
    • H04B10/505—Laser transmitters using external modulation
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/10—Optical coatings produced by application to, or surface treatment of, optical elements
    • G02B1/11—Anti-reflection coatings
    • G02B1/118—Anti-reflection coatings having sub-optical wavelength surface structures designed to provide an enhanced transmittance, e.g. moth-eye structures
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/42—Coupling light guides with opto-electronic elements
    • G02B6/4201—Packages, e.g. shape, construction, internal or external details
    • G02B6/4204—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms
    • G02B6/4215—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms the intermediate optical elements being wavelength selective optical elements, e.g. variable wavelength optical modules or wavelength lockers
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F2201/00—Constructional arrangements not provided for in groups G02F1/00 - G02F7/00
    • G02F2201/12—Constructional arrangements not provided for in groups G02F1/00 - G02F7/00 electrode
    • G02F2201/122—Constructional arrangements not provided for in groups G02F1/00 - G02F7/00 electrode having a particular pattern
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F2201/00—Constructional arrangements not provided for in groups G02F1/00 - G02F7/00
    • G02F2201/15—Constructional arrangements not provided for in groups G02F1/00 - G02F7/00 periodic
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F2201/00—Constructional arrangements not provided for in groups G02F1/00 - G02F7/00
    • G02F2201/30—Constructional arrangements not provided for in groups G02F1/00 - G02F7/00 grating
    • G02F2201/305—Constructional arrangements not provided for in groups G02F1/00 - G02F7/00 grating diffraction grating
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F2203/00—Function characteristic
    • G02F2203/62—Switchable arrangements whereby the element being usually not switchable

Definitions

  • the present invention relates to a modulator, a transmitter, and a communication system.
  • white LEDs using a combination of a short wavelength LED element made of a nitride semiconductor and a phosphor have been put into practical use, and the white LED is expected as a light source for future illumination. Unlike incandescent bulbs and fluorescent lamps, which are conventional illumination light sources, white LEDs can modulate light at a relatively high speed, and are expected to be applied to visible light communication utilizing this feature. Research projects aiming to build information communication networks in offices and homes such as the Internet through visible light communication of 1 to 10 Mbps from lighting devices are being actively promoted in Japan and overseas.
  • this type of visible light communication device a device that drives a blue light excitation type white LED based on a drive current signal generated based on transmission data and outputs a visible light signal to a receiver is proposed. ing.
  • this visible light communication device generates a multi-tone drive current signal by adding a rising pulse at the rising edge of transmission data and adding a falling pulse at the falling edge of transmission data. It is described that a multi-tone drive means is provided.
  • the current broadband communication using optical fibers and the like has reached 1000 Mbps, and compared with this, the transfer speed in the configuration using the light of the conventional LED or incandescent bulb is not sufficient.
  • total transfer rate refers to the overall data transfer rate considering both the transfer rate by a single transmitter and the capacity to operate multiple transmitters in parallel. means.
  • a modulator includes a spectroscopic unit that splits light including a plurality of wavelengths into a plurality of lights having different wavelengths, and a plurality of modulation units.
  • Each includes a structure including a material having concave or convex portions formed periodically on the surface, and an electric field adjusting unit that generates an electric field that changes in the material and changes the refractive index of the material, and includes a modulation unit.
  • Each modulates one of the plurality of light by a change in refractive index.
  • the electric field adjusting unit changes the refractive index to change the light amount at the same speed as the change in the refractive index.
  • the electric field adjustment unit of each modulation unit modulates different spectra in parallel.
  • the period in which the concave portion or the convex portion is formed may be different.
  • the period in which the concave portion or the convex portion is formed may be longer than the optical wavelength of the light modulated by the modulation means and smaller than the coherent length of the light modulated by the modulation means. .
  • a transmitter according to the present invention includes a light source that emits light including a plurality of wavelengths, and the modulator described above.
  • a communication system according to the present invention includes the above-described transmitter and a receiver having light detection means for detecting a plurality of lights.
  • the modulator, transmitter, and communication system of the present invention can improve the total data transfer rate by improving the data transfer rate and transfer capacity.
  • FIG. 10 is a diagram showing changes in signal contents in the second embodiment. It is a schematic diagram which shows the modification of the modulation
  • FIG. 1 is a schematic diagram showing an outline of a configuration of a communication system according to the present invention.
  • the communication system according to the present invention includes a transmitter 10 and a receiver 20.
  • a DC power supply 30 is connected to the transmitter 10, and the DC power supply 30 supplies power to the transmitter 10.
  • the transmitter 10 includes a white LED 11 as a light source.
  • the white LED 11 emits, for example, white light L as light including a plurality of wavelengths.
  • the transmitter 10 also includes a modulator 12.
  • the modulator 12 modulates the light emitted from the white LED 11 based on an input signal (described later with reference to FIGS. 2 to 4).
  • the modulator 12 includes an AWG (arrayed waveguide grating) 13 as spectroscopic means.
  • the AWG 13 splits the white light L emitted from the white LED 11 into a plurality of lights having different wavelengths. In the example of FIG. 1, the light is split into four light beams, La to Ld.
  • the spectral wavelength is the shortest in the spectral La, and becomes longer in the order of the spectral Lb, Lc, and Ld.
  • the number of spectra is four for convenience of explanation, but it is theoretically possible to split up to 400.
  • the modulator 12 includes a plurality of modulation means 14. Each of the modulation means 14 modulates this corresponding to any one of the spectra La to Ld. In FIG. 1, the modulators 14a to 14d are in order from those corresponding to the short wavelength spectrum.
  • the light beams La to Ld modulated by the modulation means 14a to 14d are referred to as signal lights La 'to Ld', respectively.
  • FIG. 2 is a schematic diagram showing an outline of the configuration of the modulation means 14a.
  • the modulation means 14a includes a first electrode layer 141, a moth-eye structure layer 142 as a structure, and a second electrode layer 143. These layers are laminated in order of the second electrode layer 143, the moth-eye structure layer 142, and the first electrode layer 141 from the side on which the spectral La is incident toward the side on which the signal light La 'is emitted.
  • a signal input power source 145 is connected to the modulation means 14a.
  • One pole of the signal input power source 145 is connected to the first electrode layer 141, and the other pole is connected to the second electrode layer 143.
  • the signal input power source 145 controls the voltage applied between the first electrode layer 141 and the second electrode layer 143 based on a signal to be transmitted.
  • the first electrode layer 141 is an n + -AlGaN layer having an AlN molar fraction of 0.2 or less.
  • the first electrode layer 141 may be made of other materials as long as the sheet resistance is smaller than that of the moth-eye structure layer 142.
  • the moth-eye structure layer 142 is formed on the first electrode layer 141, and convex portions 144 protruding to the second electrode layer 143 side are periodically formed.
  • each convex portion 144 is formed in alignment with the intersection of the virtual triangular lattice at a predetermined cycle so that the center is the position of the apex of the regular triangle in plan view.
  • the period of each convex part 144 is larger than the optical wavelength of the spectral La and smaller than the coherent length of the spectral La.
  • the period refers to the distance between the peak positions of the depths of the adjacent convex portions 144.
  • the optical wavelength means a value obtained by dividing the actual wavelength by the refractive index.
  • the coherent length corresponds to a distance until the periodic vibrations of the waves cancel each other and the coherence disappears due to the difference in the individual wavelengths of the photon group having a predetermined spectral width.
  • the period of each convex part 144 is preferably larger than twice the optical wavelength of the spectrum La. Moreover, it is preferable that the period of each convex part 144 is below half of the coherent length of spectroscopy La.
  • the period of each convex portion 144 is 500 nm. If the wavelength of the spectral La is 450 nm, for example, the refractive index of the group III nitride semiconductor layer is 2.4, so the optical wavelength is 187.5 nm. If the half width of the spectrum La is 63 nm, the coherent length is 3214 nm. That is, the period of each convex part 144 is larger than twice the optical wavelength of the spectrum La and is equal to or less than half of the coherent length.
  • each convex portion 144 is formed in a conical shape whose diameter is reduced toward the tip. Specifically, each convex portion 144 has a base end portion with a diameter of 200 nm and a depth of 250 nm. The tip of each convex portion 144 may have a sharp shape (for example, FIG. 3) or may have a non-pointed shape (for example, a flat shape as in FIG. 4). Further, the surface of the moth-eye structure layer 142 is flat except for the convex portions 144.
  • the moth-eye structure layer 142 as the structure is preferably made of a material having a large Pockels effect. Specifically, it is preferable to have piezoelectricity, and more preferably an isotropic crystal.
  • the moth-eye structure layer 142 can be formed of, for example, SiO 2 , AlN, LiNbO 3 , ZnO, ITO, or the like, and is formed of AlN in this embodiment.
  • the shape of each convex portion 144 can be a cone, a polygonal pyramid, or the like. In the present embodiment, a light diffraction effect can be obtained by the convex portions 144 arranged periodically.
  • the second electrode layer 143 is formed along the surface of the moth-eye structure layer 142.
  • the second electrode layer 143 is composed of an n + -AIGaN layer having an AlN molar fraction of 0.2 or less.
  • the second electrode layer 143 may be made of other materials as long as the sheet resistance is smaller than that of the moth-eye structure layer 142.
  • n1 is the refractive index of the medium on the incident side
  • ⁇ is the wavelength of the incident light
  • m is an integer.
  • n1 is the refractive index of air.
  • n2 is the refractive index of the medium on the exit side
  • m ′ is an integer.
  • n2 is the refractive index of the moth-eye structure layer 142. That is, when the refractive index of the moth-eye structure layer 142 changes, the light transmission condition changes.
  • the period of each convex portion 144 is the optical wavelength inside the element ( ⁇ / n 1 ) Or ( ⁇ / n2).
  • the generally known moth-eye structure has a period set smaller than ( ⁇ / n1) or ( ⁇ / n2), and there is no diffracted light.
  • the period of each convex part 144 must be smaller than the coherent length which light can maintain the property as a wave, and it is preferable to set it as the half or less of coherent length. By setting it to half or less of the coherent length, the intensity of reflected light and transmitted light by diffraction can be secured.
  • the refractive index of the material of the moth-eye structure layer 142 changes.
  • the refractive index of the moth-eye structure layer 142 changes, n2 in the above equation (2) changes and the diffraction transmission condition changes.
  • the light quantity of the signal light La ′ can be changed by changing the potential of the first electrode layer 141. That is, the first electrode layer 141 functions as a refractive index modulation electrode.
  • the first electrode layer 141 and the second electrode layer 143 function as an electric field adjustment unit that changes the refractive index of the material of the moth-eye structure layer 142.
  • the light can be modulated in accordance with the electric field generated in the moth-eye structure layer 142, and the modulation speed can be greatly improved as compared with the conventional method in which the on / off of light emission by the white LED 11 is controlled and modulated. it can.
  • the moth-eye structure layer 142 is sandwiched between a pair of layers having a smaller sheet resistance than the moth-eye structure layer 142, an electric field can be reliably generated in the moth-eye structure layer 142.
  • the configuration of the modulation means 14b to 14b is the same.
  • the modulation means 14a to 14d modulate the spectra La to Ld having different wavelengths, the dimensions depending on the wavelength in the configuration are different.
  • a person skilled in the art can design other modulation means 14b to 14d by making necessary changes in accordance with the wavelength of light to be modulated based on the description of the configuration of the modulation means 14a.
  • the period at which the convex portion of the moth-eye structure layer is formed in the modulating unit 14b is not 500 nm as in the modulating unit 14a, but is determined to be an optimal value based on the optical wavelength, coherent length, etc.
  • the modulation means 14a is the smallest, and thereafter increases in the order of the modulation means 14b, 14c, 14d.
  • the modulation means 14a to 14d modulate one of the plurality of spectral lines La to Lb by changing the refractive index of the material of the moth-eye structure layer included therein.
  • the modulation means 14a to 14d modulate the corresponding spectrum based on different signals. That is, different information can be given to each wavelength of light. Since the modulation means 14a to 14d can operate simultaneously, the spectrums La to Ld can be modulated and transmitted in parallel based on the four types of signals, and the signal transfer capacity can be increased.
  • FIG. 5 is a schematic diagram showing an outline of the configuration of the receiver 20.
  • the receiver 20 includes a plurality of optical filters 21 and a plurality of light detection means 22.
  • the optical filter 21 and the light detection means 22 are provided corresponding to the signal lights La ′ to Ld ′.
  • the optical filter 21a transmits light having a wavelength corresponding to the signal light La '
  • the light detection unit 22a detects light having a wavelength corresponding to the signal light La'.
  • the light detection means 22a to 22d can be configured by a phototransistor, a photodiode, a photo IC, or the like having an operation speed that can correspond to the modulation speed of the modulation means 14.
  • an optical filter corresponding to a different wavelength may be provided for each light receiving element (or each group of light receiving elements).
  • the optical filters 21a to 21d may be arranged in the same chip as the light detection means 22a to 22d, or may be arranged outside the chip.
  • the receiver 20 separates and detects the signal lights La ′ to Ld ′ having different wavelengths based on the wavelengths, so that even if the signal lights La ′ to Ld ′ are spatially overlapped, they are detected. Can be received separately. That is, even when the distance between the transmitter 10 and the receiver 20 is large and the modulation means 14 cannot be individually recognized with the resolution (spatial resolution) of the receiver 20, the signal lights La ′ to Ld ′ are spectrally reflected. Can be received separately.
  • high-speed modulation can be performed using the electric field generated in the moth-eye structure layer 142, so that the data transfer rate is improved. Can do.
  • the data transfer capacity can be improved. Therefore, the total transfer rate in visible light communication can be improved by improving the transfer rate and transfer capacity.
  • the white LED 11 is used as a light source, the light source for indoor illumination can be diverted or shared for information transfer.
  • Embodiment 2 a part of the signal light La ′ to Ld ′ is a dummy in the first embodiment, and the signal light corresponding to the actual signal is changed with time.
  • Such an embodiment is useful, for example, in cryptographic communications.
  • FIG. 6 shows changes in signal contents in the communication system according to the second embodiment.
  • modulation means 14a and 14b perform modulation based on an actual signal to be transmitted
  • modulation means 14c and 14d perform modulation based on a dummy signal not related to the actual signal. That is, the signal lights La ′ and Lb ′ represent actual signals, and the signal lights Lc ′ and Ld ′ represent dummy signals.
  • real signals are represented by solid lines, and dummy signals are represented by broken lines.
  • period 2 a part or all of the modulation means using the real signal and the modulation means using the dummy signal are switched.
  • the signal lights La ′ and Ld ′ represent actual signals
  • the signal lights Lb ′ and Lc ′ represent dummy signals.
  • the signal lights Lb ′ and Lc ′ represent actual signals
  • the signal lights La ′ and Ld ′ represent dummy signals.
  • information indicating which of the wavelengths represents a real signal and which of the wavelengths represents a dummy signal is obtained from the receiving device (for example, a receiver or a demodulator) by any method. Communicated or stored in advance. Therefore, on the receiving side, only those representing the actual signal among the wavelengths can be selected, and the original signal can be restored using these.
  • the frequency of the signal light representing the actual signal varies with time. For this reason, even if the signal lights La ′ to Ld ′ are intercepted or eavesdropped, it is difficult to restore the original signal if any of them is concealed as to whether it is a real signal or which is a dummy signal. . Therefore, the confidentiality of communication can be improved.
  • the number of modulation means is four, but 400 modulation means can actually be provided as described above, and a highly confidential communication method can be realized.
  • the switching method between the real signal and the dummy signal can be appropriately designed using a well-known encryption communication protocol.
  • there are two modulation means corresponding to the actual signal in each period but this may be a different number, or there may be a period in which all the modulation means transmit the actual signal. There may be a period in which all modulation means transmit dummy signals.
  • the moth-eye structure layer 142 is formed of AlN.
  • n-type GaN layers 142b and AlN layers 142a are alternately stacked. May be formed.
  • the refractive index change of the moth-eye structure layer 142 can be increased.
  • the amount of change in the refractive index is smaller than that of the Pockels effect, the refractive index is changed using the Kerr effect. You can also.
  • the convex portion 144 of the moth-eye structure layer 142 is convex toward the incident side, but this may be formed in the opposite direction.
  • An example of such a configuration is shown in FIG.
  • the modulation means 24 in FIG. 8 includes a first electrode layer 241, a moth-eye structure layer 242 as a structure, and a second electrode layer 243. These layers are laminated in the order of the first electrode layer 241, the moth-eye structure layer 242, and the second electrode layer 243 from the side on which the spectrum L2 is incident to the side on which the signal light L2 'is emitted.
  • the convex portion 244 of the moth-eye structure layer 242 is formed in a direction that is convex toward the side from which the signal light L2 'is emitted. Further, a signal input power source 245 is connected to the modulation means 24.
  • the moth-eye structure layer 142 is periodically formed with the convex portions 144, but the concave portions may be periodically formed.
  • the convex portion or the concave portion may be formed in a prismatic shape and aligned with intersections of a virtual square lattice at a predetermined period.
  • the convex portion or the concave portion may be a polygonal pyramid shape that is reduced in diameter toward the tip, such as a triangular pyramid shape or a quadrangular pyramid shape, and it is needless to say that a specific detailed structure and the like can be appropriately changed. .
  • the modulation means 14a to 14d perform modulation based on different information, but a plurality of modulation means may perform modulation based on the same information. In this case, the redundancy of transmitted information can be improved and transmission errors can be suppressed.
  • the white LED 11 is used as the light source, but other configurations may be used as long as the light source emits light including a plurality of wavelengths.
  • a monochromatic LED having a spectral width that can be dispersed may be used.
  • An incandescent bulb or a fluorescent lamp may be used. These may be diverted or used as a light source for indoor lighting.
  • the medium that meshes with the convex portion 144 of the moth-eye structure layer 142 is air, but this may not be air, and a layer of another medium may be provided.
  • the refractive index n1 of the incident side medium in FIG. 3 is the refractive index of the epoxy resin.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Nonlinear Science (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Chemical & Material Sciences (AREA)
  • Electromagnetism (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)
  • Optical Communication System (AREA)

Abstract

L'invention concerne un modulateur, un émetteur et un système de communication qui améliorent le débit total de transfert de données. Un AWG (13) disperse la lumière blanche (L) émise par une DEL blanche (11) en plusieurs composantes spectrales (La-Ld) ayant chacune une longueur d'onde différente. Le modulateur (12) comporte plusieurs moyens de modulation (14a-14d). Un moyen de modulation (14a) génère un champ électrique variable dans la matière d'une couche de structure en oeil de papillon (142) par l'application d'une tension sur une première couche d'électrode (141) et une seconde couche d'électrode (143), et modifie l'indice de réfraction de ladite matière en vue de moduler la composante spectrale (La). Les autres moyens de modulation (14b-14d) modulent les composantes spectrales (Lb-Ld) de la même manière. Les moyens de modulation (14a-14d) modulent les composantes spectrales (La-Ld) sur la base de signaux différents.
PCT/JP2011/072196 2010-12-24 2011-09-28 Modulateur, émetteur et système de communication WO2012086283A1 (fr)

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JP5809617B2 (ja) * 2012-12-26 2015-11-11 富士通テレコムネットワークス株式会社 伝送システムおよび伝送装置
WO2017010743A1 (fr) * 2015-07-10 2017-01-19 한양대학교 에리카산학협력단 Module de transmission optique, émetteur-récepteur optique et système de communication optique incluant ce module et cet émetteur-récepteur
KR101848804B1 (ko) 2015-07-10 2018-04-16 한양대학교 에리카산학협력단 광 송신모듈, 광 트랜시버, 및 이를 포함하는 광통신 시스템
KR101876949B1 (ko) * 2015-07-10 2018-07-11 한양대학교 에리카산학협력단 광 송신모듈, 광 트랜시버, 및 이를 포함하는 광통신 시스템
JP6674207B2 (ja) * 2015-08-06 2020-04-01 ダイトロン株式会社 空間光伝送装置

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