Frequency conversion device and communication device

Abstract

A frequency conversion device (1) is configured to be provided with: an optical wavelength division multiplexing unit (13) for wavelength division multiplexing carrier light and pilot light having a wavelength different from that of the carrier light; and a light intensity modulation unit (14) for modulating the light intensity of the carrier light multiplexed by the pilot light multiplexed by the optical wavelength division multiplexing unit (13) using a signal to be converted in frequency, and outputting intensity-modulated light as the carrier light after the light intensity modulation. Furthermore, the frequency conversion device (1) is provided with: an optical wavelength division unit (15) for dividing the intensity-modulated light output from the light intensity modulation unit (14) into a wavelength component of carrier light and a wavelength component of pilot light; an optical pulse compression unit (16) that compresses the wavelength component of the carrier light in the time direction and outputs time-compressed pulsed light that is the wavelength component of the compressed carrier light; and a control unit (18) that controls the light intensity modulation by the light intensity modulation unit (14) on the basis of the wavelength component of the pilot light.

Description

Technical Field

[0001] The present disclosure relates to a frequency conversion device and a communication device. Background Art

[0002] There is a frequency conversion device that converts the frequency of a signal to be frequency converted.

[0003] As such a frequency converter, for example, Patent Document 1 discloses a device including an optical carrier generator, a modulator, a dispersion compensator, and an optoelectronic converter.

[0004] The optical carrier generator generates an optical carrier. The modulator modulates the optical carrier generated by the optical carrier generator using a first electrical signal. The first electrical signal is the signal to be frequency-converted. The dispersion compensator compresses the optical carrier modulated by the modulator in the time domain. The photoelectric converter converts the optical carrier compressed by the dispersion compensator into a second electrical signal. The second electrical signal is a frequency-converted signal having a higher frequency than the first electrical signal.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: International Publication No. 2021 / 079710 Summary of the Invention

[0008] Problems to be solved by the invention

[0009] In the device disclosed in Patent Document 1, for example, temperature drift may occur in the modulator due to changes in the ambient temperature of the modulator. Furthermore, temporal drift may occur in the modulator over time. Temperature drift or temporal drift in the modulator may cause the signal level of the second electrical signal to deviate from its original signal level.

[0010] The present disclosure is made to solve the above problems, and its purpose is to provide a frequency conversion device that can restore the signal level of the frequency-converted signal to the original signal level even if the signal level of the frequency-converted signal deviates from the original signal level.

[0011] Means used to solve problems

[0012] The frequency conversion device disclosed herein comprises: an optical wavelength division multiplexing unit that wavelength-division multiplexes pilot light having a wavelength different from that of the carrier light with the carrier light; an optical intensity modulating unit that modulates the optical intensity of the carrier light multiplexed with the pilot light by the optical wavelength division multiplexing unit using a signal to be frequency converted, thereby outputting intensity-modulated light as the carrier light after optical intensity modulated. Furthermore, the frequency conversion device comprises: an optical wavelength demultiplexing unit that demultiplexes the intensity-modulated light output from the optical intensity modulating unit into a wavelength component of the carrier light and a wavelength component of the pilot light; an optical pulse compression unit that compresses the wavelength component of the carrier light in the temporal direction and outputs time-compressed pulse light as the compressed wavelength component of the carrier light; and a control unit that controls the optical intensity modulation of the optical intensity modulating unit based on the wavelength component of the pilot light.

[0013] Effects of the Invention

[0014] According to the present disclosure, even if the signal level of a frequency-converted signal, which is an electrical signal converted from time-compressed pulse light, deviates from the original signal level, the signal level of the frequency-converted signal can be restored to the original signal level. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 1 is a diagram showing the configuration of a communication device including the frequency converter 1 according to the first embodiment.

[0016] Figure 2 1 is a diagram showing the configuration of the frequency converter 1 according to the first embodiment.

[0017] Figure 3 is a graph showing a short pulse light P C and carrier optical P CAR 's illustration.

[0018] Figure 4A It shows the carrier light P CAR and pilot light P PIL Illustration of the respective time waveforms, Figure 4B It shows the pilot light P PIL The carrier light P obtained by wavelength division multiplexing CAR+PIL , Figure 4C It shows the carrier light P CAR and pilot light P PIL Illustration of the respective wavelengths.

[0019] Figure 5 It is an explanatory diagram showing the time waveform of the RF signal (1).

[0020] Figure 6 is a graph showing the intensity modulated light P IM An illustration of the time waveform of .

[0021] Figure 7A It shows the carrier light P CAR An illustration of the time waveform of the wavelength component of Figure 7B is a graph showing the pilot light P PIL An illustration of the time waveform of the wavelength component.

[0022] Figure 8 is a time-compressed pulse light P TC An illustration of the time waveform of .

[0023] Figure 9 It is an explanatory diagram showing the time waveform of the RF signal (2).

[0024] Figure 10 This is a diagram showing the configuration of a frequency converter 1 according to a second embodiment.

[0025] Figure 11A The carrier light P after waveform shaping is shown. CAR ' and pilot light P PIL Illustration of the respective time waveforms, Figure 11B It shows the pilot light P PIL The carrier light P after waveform shaping obtained by wavelength division multiplexing CAR’+PIL , Figure 11C It shows the carrier light P CAR ' and pilot light P PIL Illustration of the respective wavelengths. DETAILED DESCRIPTION

[0026] Hereinafter, in order to explain the present disclosure in more detail, modes for implementing the present disclosure will be described with reference to the accompanying drawings.

[0027] Implementation method 1.

[0028] Figure 1 1 is a diagram showing the configuration of a communication device including the frequency converter 1 according to the first embodiment.

[0029] Figure 1 The communication device shown includes a frequency converter 1 , a communication circuit 2 , and an antenna 3 .

[0030] The frequency converter 1 is a device that converts the frequency f1 of an RF (Radio Frequency) signal (1) as a frequency conversion target signal into another frequency f2 and outputs an RF signal (2) having the frequency f2.

[0031] The frequency converter 1 outputs the frequency-converted RF signal ( 2 ) to the communication circuit 2 .

[0032] The frequency f2 of the RF signal (2) is, for example, a frequency in the microwave band, a frequency in the millimeter wave band, or a frequency in the terahertz wave band.

[0033] exist Figure 1 In the example shown in FIG. 1 , the frequency converter 1 is mounted on a communication device. However, this is merely an example, and the frequency converter 1 may be mounted on a device other than a communication device.

[0034] The communication circuit 2 outputs the RF signal ( 2 ) output from the frequency converter 1 to the antenna 3 .

[0035] Furthermore, the communication circuit 2 performs normal signal processing such as modulation processing on the RF signal (2) output from the frequency converter 1. The RF signal (2) output from the communication circuit 2 to the antenna 3 is a signal subjected to modulation processing such as modulation processing by the communication circuit 2. Normal signal processing such as modulation processing on the RF signal (2) is a well-known technique, and therefore a detailed description thereof will be omitted.

[0036] The antenna 3 radiates radio waves based on the RF signal (2) output from the communication circuit 2 into space.

[0037] Figure 2 1 is a diagram showing the configuration of the frequency converter 1 according to the first embodiment.

[0038] Figure 2 The frequency converter 1 shown includes a carrier light generator 11 , a pilot light generator 12 , an optical wavelength division multiplexer 13 , an optical intensity modulator 14 , an optical wavelength demultiplexer 15 , an optical pulse compressor 16 , a photoelectric converter 17 , and a controller 18 .

[0039] exist Figure 2 In the frequency conversion device 1 shown, the carrier light generating unit 11 and the optical wavelength division multiplexing unit 13, the pilot light generating unit 12 and the optical wavelength division multiplexing unit 13, the optical wavelength division multiplexing unit 13 and the optical intensity modulating unit 14, the optical intensity modulating unit 14 and the optical wavelength demultiplexing unit 15, the optical wavelength demultiplexing unit 15 and the optical pulse compressing unit 16, the optical pulse compressing unit 16 and the photoelectric converter 17, and the optical wavelength demultiplexing unit 15 and the control unit 18 are respectively connected by, for example, optical fibers.

[0040] The carrier light generating unit 11 includes a short pulse light source 11 a and an optical pulse stretching unit 11 b .

[0041] The carrier light generating unit 11 generates a wavelength λ C [nm] pulsed light (hereinafter referred to as "short pulse light") P C The carrier light P is generated by spreading in the time direction CAR , the generated carrier light P CAR The signal is output to the optical wavelength division multiplexing unit 13 .

[0042] The short pulse light source 11 a is realized by, for example, a mode-locked fiber laser.

[0043] The short pulse light source 11a repeatedly oscillates at a wavelength λ C [nm] short pulse light P C , repeatedly short pulse light P C Output to the optical pulse stretching unit 11b. Short pulse light P C The pulse width is W1, the short pulse P C The oscillation period is D.

[0044] The optical pulse stretching unit 11 b is realized by, for example, a passive optical component using a dispersive medium.

[0045] The optical pulse stretching unit 11b stretches the short pulse light P outputted from the short pulse light source 11a. C Wavelength dispersion that is broadened in the time direction.

[0046] The optical pulse stretching unit 11b converts the carrier light P which is the wavelength-dispersed short pulse light into CAR Output to the optical wavelength division multiplexing unit 13. Carrier light P CAR The band is, for example, λ C -α to λ C +α range.

[0047] The pilot light generating unit 12 includes a light source driving circuit 12 a and a pilot light source 12 b .

[0048] The pilot light generating unit 12 generates the same carrier light P as that generated by the carrier light generating unit 11. CAR Different wavelengths λ P [nm] of pilot light P PIL , the generated pilot light P PIL The signal is output to the optical wavelength division multiplexing unit 13 .

[0049] The light source driving circuit 12 a is implemented by, for example, an FPGA (Field Programmable Gate Array).

[0050] The light source driving circuit 12 a is a control circuit that drives the pilot light source 12 b so that continuous light (hereinafter referred to as “CW light”) is output from the pilot light source 12 b.

[0051] The pilot light source 12b is realized by, for example, a semiconductor laser.

[0052] The pilot light source 12b oscillates CW light as a CAR Different wavelengths λ P The pilot light P PIL , the pilot light P PIL The signal is output to the optical wavelength division multiplexing unit 13 .

[0053] The optical wavelength division multiplexing unit 13 includes, for example, a wavelength division multiplexing coupler, an arrayed waveguide grating, and an optical multiplexer.

[0054] The optical wavelength division multiplexing unit 13 is supplied with the carrier light P from the carrier light generating unit 11. CAR , the pilot light P is supplied from the pilot light generating unit 12. PIL .

[0055] The optical wavelength division multiplexing unit 13 makes the pilot light P PIL With carrier optical P CAR Perform wavelength division multiplexing to generate carrier optical P CAR+PIL . Carrier optical P CAR+PIL It is the carrier light after the pilot light is multiplexed.

[0056] The optical wavelength division multiplexing unit 13 converts the carrier light P CAR+PIL The signal is output to the light intensity modulation unit 14 .

[0057] The light intensity modulator 14 is implemented by, for example, a Mach-Zehnder modulator, an electro-absorption modulator, or an acousto-optic modulator.

[0058] The optical intensity modulator 14 is supplied with an RF signal (1) as a signal to be frequency-converted from the outside, and is supplied with a carrier wave optical signal P from the optical wavelength division multiplexing unit 13. CAR+PIL , a bias signal B is provided from the control unit 18.

[0059] The optical intensity modulation unit 14 modulates the carrier light P using the RF signal (1). CAR+PIL The light intensity modulation performed by the light intensity modulation unit 14 is controlled by the bias signal B.

[0060] The light intensity modulation unit 14 modulates the intensity modulated light P which is the carrier light after light intensity modulation. IM The signal is output to the optical wavelength demultiplexing section 15 .

[0061] The optical wavelength demultiplexing unit 15 includes, for example, a wavelength division multiplexing coupler, an arrayed waveguide grating, and an optical demultiplexer.

[0062] The optical wavelength demultiplexer 15 is supplied with the intensity modulated light P from the optical intensity modulator 14. IM .

[0063] The optical wavelength demultiplexer 15 converts the intensity modulated light P IM The carrier light P CAR The wavelength components and pilot light P PIL wavelength components.

[0064] The optical wavelength demultiplexing unit 15 converts the carrier light P CAR The wavelength component of the pilot light P is output to the optical pulse compression unit 16. PIL The wavelength component is output to the control unit 18.

[0065] The optical pulse compressor 16 is realized by, for example, a passive optical component using a dispersive medium.

[0066] The optical pulse compression unit 16 is supplied with the carrier light P from the optical wavelength demultiplexing unit 15. CAR wavelength components.

[0067] The optical pulse compression unit 16 compresses the carrier light P CAR The wavelength components are compressed in the time direction.

[0068] The optical pulse compressor 16 converts the compressed carrier light P CAR The wavelength component of the time-compressed pulse light P TC Output to the photoelectric conversion unit 17.

[0069] The photoelectric conversion unit 17 is realized by, for example, a photodiode.

[0070] The photoelectric converter 17 is supplied with the time-compressed pulse light P from the optical pulse compressor 16. TC .

[0071] The photoelectric conversion unit 17 converts the time-compressed pulse light P TC The RF signal (2) is converted into an electrical signal, and the electrical signal is output as a frequency-converted signal to the communication circuit 2. The frequency f2 of the RF signal (2) is higher than the frequency f1 of the RF signal (1).

[0072] exist Figure 2 In the frequency converter 1 shown, the photoelectric converter 17 outputs the RF signal (2) to the communication circuit 2. However, this is merely an example, and the photoelectric converter 17 may output the RF signal (2) to a device other than the communication circuit 2.

[0073] The control unit 8 includes a photoelectric conversion unit 18 a and a bias control circuit 18 b .

[0074] The control unit 8 is supplied with the pilot light P from the optical wavelength demultiplexing unit 15. PIL wavelength components.

[0075] The control unit 8 is based on the pilot light P PIL The wavelength component of the light intensity modulation unit 14 is controlled to modulate the light intensity.

[0076] The photoelectric conversion unit 18 a is realized by, for example, a photodiode.

[0077] The photoelectric converter 18a is supplied with the pilot light P from the optical wavelength demultiplexer 15. PIL wavelength components.

[0078] The photoelectric conversion unit 18a converts the pilot light P PILThe wavelength component of the wavelength is converted into an electrical signal E, and the electrical signal E is output to the bias control circuit 18b.

[0079] The bias control circuit 18b is implemented by, for example, a bias controller.

[0080] The bias control circuit 18b is supplied with the electric signal E from the photoelectric conversion unit 18a.

[0081] The bias control circuit 18 b controls the bias signal B supplied to the light intensity modulator 14 based on the electric signal E, thereby controlling the light intensity modulation performed by the light intensity modulator 14 .

[0082] Then, Figure 2 The operation of the frequency converter 1 shown will be described.

[0083] like Figure 3 As shown, the short pulse light source 11a of the carrier light generating unit 11 repeatedly oscillates the wavelength λ C Short pulse light P C .

[0084] The short pulse light source 11a generates short pulse light P C The light is repeatedly output to the optical pulse stretching unit 11b.

[0085] The light pulse stretching unit 11b receives the short pulse light P from the short pulse light source 11a. C When, such as Figure 3 As shown, the short pulse light P C Wavelength dispersion that is broadened in the time direction.

[0086] The optical pulse stretching unit 11b converts the carrier light P which is the wavelength-dispersed short pulse light into CAR The signal is output to the optical wavelength division multiplexing unit 13 .

[0087] Figure 3 is a graph showing a short pulse light P C and carrier optical P CAR 's illustration.

[0088] exist Figure 3 In the figure, the horizontal axis represents time and the vertical axis represents short pulse light P C and carrier optical P CAR Respective light intensity.

[0089] W1 is a short pulse light P C The pulse width D is based on the short pulse light P of the short pulse light source 11a. C oscillation period.

[0090] W2 is the carrier optical P CAR pulse width.

[0091] G is two carrier waves P adjacent in time. CAR gap time.

[0092] The gap time G is when the optical intensity modulation unit 14 cannot modulate the carrier light P via the RF signal (1). CAR+PIL The time for light intensity modulation. Carrier light P CAR The wider the pulse width W2 and the shorter the gap time G, the less likely it is that the carrier light P is modulated by the RF signal (1) in the optical intensity modulation unit 14. CAR+PIL In other words, in the optical intensity modulation unit 14, the carrier light P can be modulated by the RF signal (1). CAR+PIL The time for performing light intensity modulation increases.

[0093] Therefore, it is desirable that the optical pulse stretching unit 11b is configured to transmit the two carrier light pulses P adjacent to each other in time. CAR Within the non-overlapping range (G≥0), the short pulse light P C Expand as much as possible in time.

[0094] like Figure 4C As shown, the pilot light source 12b of the pilot light generating unit 12 oscillates CW light as a carrier light P CAR Different wavelengths λ P The pilot light P PIL . Pilot light P PIL Wavelength λ P [nm] is the wavelength of the carrier light P CAR The wavelengths of the bands do not overlap.

[0095] exist Figure 4C In the figure, the pilot light P is shown. PIL Wavelength λ P Carrier light P CAR However, this is just an example. PIL Wavelength λ P It can also be compared with the carrier optical P CAR The band is short.

[0096] The oscillation of the CW light by the pilot light source 12 b is controlled by the light source driving circuit 12 a .

[0097] The pilot light source 12b transmits the pilot light P PIL The signal is output to the optical wavelength division multiplexing unit 13 .

[0098] Figure 4A It shows the carrier light P CAR and pilot light P PIL The following diagrams illustrate the respective time waveforms. Figure 4A In the figure, the horizontal axis represents time and the vertical axis represents the carrier light P CAR and pilot light PPIL Respective light intensity.

[0099] Figure 4B It shows the pilot light P PIL The carrier light P obtained by wavelength division multiplexing CAR+PIL In the illustration. Figure 4B In the figure, the horizontal axis represents time and the vertical axis represents the carrier light P CAR+PIL light intensity.

[0100] Figure 4C It shows the carrier light P CAR and pilot light P PIL The diagram below shows the wavelengths of the light. Figure 4C In the figure, the horizontal axis represents wavelength and the vertical axis represents carrier light P. CAR and pilot light P PIL Respective light intensity.

[0101] exist Figure 4A In the example, the pilot light P PIL The light intensity is greater than the carrier light P CAR However, this is just an example. PIL The light intensity is not limited to the carrier light P CAR However, the pilot light P output from the pilot light source 12b is PIL The light intensity is a fixed light intensity.

[0102] like Figure 4C As shown, the pilot light P PIL The wavelength of the carrier light P CAR The wavelengths of the wavelengths do not interfere.

[0103] The optical wavelength division multiplexing unit 13 is provided with the optical wavelength division multiplexing unit 13 from the carrier light generating unit 11. Figure 4A The carrier light P CAR , is provided from the pilot light generating unit 12 Figure 4A The pilot light P shown PIL .

[0104] The optical wavelength division multiplexing unit 13 makes the pilot light P PIL With carrier optical P CAR Perform wavelength division multiplexing to generate Figure 4B The carrier light P CAR+PIL .

[0105] The optical wavelength division multiplexing unit 13 converts the carrier light P CAR+PIL The signal is output to the light intensity modulation unit 14 .

[0106] The light intensity modulation unit 14 is provided from the outside Figure 5 The RF signal (1) shown is supplied with a carrier wave optical signal P from the optical wavelength division multiplexing unit 13. CAR+PIL, a bias signal B is provided from the control unit 18.

[0107] Figure 5 It is an explanatory diagram showing the time waveform of the RF signal (1).

[0108] exist Figure 5 In FIG, the horizontal axis represents time, and the vertical axis represents the light intensity of the RF signal (1).

[0109] The optical intensity modulation unit 14 modulates the carrier light P by the RF signal (1). CAR+PIL Perform light intensity modulation.

[0110] The light intensity modulation unit 14 modulates the intensity modulated light P which is the carrier light after light intensity modulation. IM The signal is output to the optical wavelength demultiplexing section 15 .

[0111] The light intensity modulation performed by the light intensity modulation unit 14 is controlled by the bias signal B. Figure 6 As shown, the intensity modulated light P IM The light intensity changes according to the time variation of the RF signal (1).

[0112] Figure 6 is a graph showing the intensity modulated light P IM An illustration of the time waveform of .

[0113] exist Figure 6 In the figure, the horizontal axis represents time and the vertical axis represents the intensity modulated light P IM light intensity.

[0114] The optical wavelength demultiplexer 15 is supplied with the intensity modulated light P from the optical intensity modulator 14. IM .

[0115] The optical wavelength demultiplexer 15 converts the intensity modulated light P IM The carrier light P CAR The wavelength components and pilot light P PIL The intensity modulated light P of the optical wavelength demultiplexer 15 is IM The wave splitting itself is a well-known technology, so the detailed description is omitted.

[0116] The optical wavelength demultiplexing unit 15 divides Figure 7A The carrier light P CAR The wavelength component is output to the optical pulse compression unit 16, Figure 7B The pilot light P shown PIL The wavelength component is output to the control unit 18.

[0117] Figure 7A It shows the carrier light P CAR An illustration of the time waveform of the wavelength component.

[0118] exist Figure 7A In the figure, the horizontal axis represents time and the vertical axis represents the carrier light P CAR The light intensity of the wavelength component.

[0119] Figure 7B is a graph showing the pilot light P PIL An illustration of the time waveform of the wavelength component.

[0120] exist Figure 7B In the figure, the horizontal axis represents time and the vertical axis represents the pilot light P PIL The light intensity of the wavelength component.

[0121] The optical pulse compression unit 16 is supplied with the carrier light P from the optical wavelength demultiplexing unit 15. CAR wavelength components.

[0122] like Figure 8 As shown, the optical pulse compression unit 16 compresses the carrier light P CAR The wavelength components are compressed in the time direction.

[0123] The optical pulse compressor 16 converts the compressed carrier light P CAR The wavelength component of the time-compressed pulse light P TC Output to the photoelectric conversion unit 17.

[0124] Figure 8 is a time-compressed pulse light P TC An illustration of the time waveform of .

[0125] exist Figure 8 In the figure, the horizontal axis represents time and the vertical axis represents time-compressed pulse light P TC light intensity.

[0126] The photoelectric converter 17 is supplied with the time-compressed pulse light P from the optical pulse compressor 16. TC .

[0127] The photoelectric conversion unit 17 converts the time-compressed pulse light P TC The RF signal (2) is converted into an electrical signal and outputted to the communication circuit 2. The RF signal (2) is a carrier light P compressed in the time direction. CAR The wavelength component of the time-compressed pulse light P TC Therefore, the frequency f2 of the RF signal (2) is higher than the frequency f1 of the RF signal (1).

[0128] Figure 9 It is an explanatory diagram showing the time waveform of the RF signal (2).

[0129] exist Figure 9 In FIG. 1 , the horizontal axis represents time, and the vertical axis represents the light intensity of the RF signal ( 2 ).

[0130] Due to temperature drift or time drift of the light intensity modulator 14, the signal level of the RF signal (2) output from the photoelectric converter 17 to the communication circuit 2 may deviate from the original signal level.

[0131] because Figure 2 The frequency converter 1 shown includes the control unit 18 , and thus can compensate for deviations in signal levels.

[0132] The photoelectric converter 18a of the control unit 8 is supplied with the pilot light P from the optical wavelength demultiplexing unit 15. PIL wavelength components.

[0133] The photoelectric conversion unit 18a converts the pilot light P PIL The wavelength component of the wavelength is converted into an electrical signal E, and the electrical signal E is output to the bias control circuit 18b.

[0134] The bias control circuit 18b is supplied with the electric signal E from the photoelectric conversion unit 18a.

[0135] The bias control circuit 18 b controls the bias signal B supplied to the light intensity modulator 14 based on the electric signal E, thereby controlling the light intensity modulation performed by the light intensity modulator 14 .

[0136] Specifically, the bias control circuit 18b compares the electric signal E with the threshold value Th.

[0137] The threshold Th indicates the value of the electric signal E output from the photoelectric converter 18a when the light intensity modulator 14 does not experience temperature drift or time drift. The value of the electric signal E when the light intensity modulator 14 does not experience temperature drift is determined by, for example, the characteristics of the light intensity modulator 14.

[0138] The threshold value Th may be stored in an internal memory of the bias control circuit 18 b or may be provided from outside the frequency converter 1 .

[0139] If the electric signal E is larger than the threshold value Th, the bias control circuit 18b controls the bias signal B supplied to the light intensity modulation section 14 so that the intensity modulated light P outputted from the light intensity modulation section 14 is equal to 1. IM The light intensity decreases.

[0140] If the electric signal E is smaller than the threshold value Th, the bias control circuit 18b controls the bias signal B supplied to the light intensity modulation section 14 so that the intensity modulated light P outputted from the light intensity modulation section 14 is equal to 1. IM The light intensity increases.

[0141] If the electric signal E is equal to the threshold value Th, the bias control circuit 18 b maintains the bias signal B supplied to the light intensity modulation section 14 .

[0142] Here, if the electric signal E is larger than the threshold value Th, the bias control circuit 18b controls the bias signal B supplied to the light intensity modulation section 14 so that the intensity modulated light P outputted from the light intensity modulation section 14 is IM However, this is just an example, and the bias control circuit 18b may control the bias signal B supplied to the light intensity modulator 14 only when the difference between the electric signal E and the threshold value Th is equal to or greater than a set value, so that the intensity modulated light P outputted from the light intensity modulator 14 is equal to or greater than the set value. IM The light intensity decreases.

[0143] If the electric signal E is smaller than the threshold value Th, the bias control circuit 18b controls the bias signal B supplied to the light intensity modulation section 14 so that the intensity modulated light P outputted from the light intensity modulation section 14 is equal to or smaller than the threshold value Th. IM However, this is just an example, and the bias control circuit 18b may control the bias signal B supplied to the light intensity modulator 14 only when the difference between the electric signal E and the threshold value Th is equal to or greater than a set value, so that the intensity modulated light P outputted from the light intensity modulator 14 is greater than 1. IM The light intensity increases.

[0144] In the first embodiment described above, the frequency converter 1 is configured to include an optical wavelength division multiplexing unit 13 that wavelength-division multiplexes pilot light having a wavelength different from that of the carrier light with the carrier light; an optical intensity modulator 14 that modulates the optical intensity of the carrier light multiplexed with the pilot light by the optical wavelength division multiplexing unit 13 using a signal to be frequency converted, thereby outputting intensity-modulated light as the carrier light after optical intensity modulation. Furthermore, the frequency converter 1 includes an optical wavelength demultiplexing unit 15 that demultiplexes the intensity-modulated light output from the optical intensity modulator 14 into a wavelength component of the carrier light and a wavelength component of the pilot light; an optical pulse compressor 16 that compresses the wavelength component of the carrier light in the temporal direction and outputs time-compressed pulse light as the compressed wavelength component of the carrier light; and a controller 18 that controls the optical intensity modulation of the optical intensity modulator 14 based on the wavelength component of the pilot light. Therefore, even if the signal level of the frequency-converted signal, which is an electrical signal converted from the time-compressed pulse light, deviates from the original signal level, the frequency converter 1 can restore the signal level of the frequency-converted signal to the original signal level.

[0145] Implementation method 2.

[0146] In the second embodiment, a frequency converter 1 including a spectrum shaping unit 19 is described. The spectrum shaping unit 19 modulates the carrier light P generated by the carrier light generating unit 11. CARThe time waveform is shaped.

[0147] Figure 10 : is a diagram showing the structure of the frequency converter 1 according to the second embodiment. Figure 10 In, with Figure 2 The same reference numerals denote the same or corresponding parts, and thus detailed descriptions thereof are omitted.

[0148] Figure 10 The frequency converter 1 shown includes a carrier light generating unit 11 , a pilot light generating unit 12 , an optical wavelength division multiplexing unit 13 , an optical intensity modulating unit 14 , an optical wavelength demultiplexing unit 15 , an optical pulse compressing unit 16 , a photoelectric converting unit 17 , a control unit 18 , and a spectrum shaping unit 19 .

[0149] exist Figure 10 In the frequency converter 1 shown, the carrier light generating section 11 and the spectrum shaping section 19 , and the spectrum shaping section 19 and the optical wavelength division multiplexing section 13 are connected, for example, via optical fibers.

[0150] The spectrum shaping unit 19 is realized by, for example, a wavelength selective switch.

[0151] The spectrum shaping unit 19 is supplied with the carrier light P from the carrier light generating unit 11. CAR .

[0152] The spectrum shaping unit 19 performs a spectrum shaping on the carrier light P CAR The time waveform is shaped.

[0153] The spectrum shaping unit 19 transforms the waveform-shaped carrier light P CAR 'Output to the optical wavelength division multiplexing unit 13.

[0154] exist Figure 10 In the frequency converter 1 shown, the spectrum shaping unit 19 is disposed between the optical pulse stretcher 11b and the optical wavelength multiplexing unit 13. However, this is merely an example, and the optical wavelength multiplexing unit 13 may also have the function of the spectrum shaping unit 19.

[0155] Then, Figure 10 The operation of the frequency converter 1 shown in FIG. Figure 2 The frequency converter 1 shown is the same, and therefore, the operation of the spectrum shaping unit 19 will be mainly described here.

[0156] like Figure 4C As shown, the carrier light P generated by the carrier light generating unit 11 CAR The light intensity at wavelength λ C The maximum wavelength is λ C The shorter the wavelength, the smaller the light intensity. C The longer the carrier light P CAR The smaller the light intensity.

[0157] That is, the carrier light P CAR The light intensity has wavelength dependence, the carrier light P CAR Sometimes distortion occurs.

[0158] The spectrum shaping unit 19 is supplied with the carrier light P from the carrier light generating unit 11. CAR .

[0159] The spectrum shaping unit 19 performs a spectrum shaping on the carrier light P CAR The time waveform is shaped to eliminate the carrier light P CAR distortion.

[0160] Figure 4A The carrier light P CAR Distortion occurs. Figure 11A The carrier light P after waveform shaping is shown CAR ''s distortion is eliminated.

[0161] Specifically, the spectrum shaping unit 19 adjusts the carrier light P CAR The optical attenuation of each frequency slice in Figure 11A As shown in the figure, the carrier light P CAR The time waveform is shaped.

[0162] The spectrum shaping unit 19 transforms the waveform-shaped carrier light P CAR 'Output to the optical wavelength division multiplexing unit 13.

[0163] Figure 11A The carrier light P after waveform shaping is shown. CAR ' and pilot light P PIL The following diagrams illustrate the respective time waveforms. Figure 11A In the figure, the horizontal axis represents time, and the vertical axis represents the carrier light P after waveform shaping. CAR ' and pilot light P PIL Respective light intensity.

[0164] Figure 11B It shows the pilot light P PIL The carrier light P after waveform shaping obtained by wavelength division multiplexing CAR’+PIL In the illustration. Figure 11B In the figure, the horizontal axis represents time and the vertical axis represents the carrier light P CAR’+PIL light intensity.

[0165] Figure 11C It shows the carrier light P CAR ' and pilot light P PIL The diagram below shows the wavelengths of the light. Figure 11C In the figure, the horizontal axis represents wavelength and the vertical axis represents carrier light P. CAR ' and pilot light P PILRespective light intensity.

[0166] exist Figure 11C In the figure, the pilot light P is shown. PIL Wavelength λ P Carrier light P CAR However, this is just an example. PIL Wavelength λ P It can also be compared with the carrier optical P CAR 'The band is short.

[0167] The spectrum shaping unit 19 is used to shape the carrier light P CAR The time waveform is shaped, thus, Figure 2 Compared with the frequency converter 1 shown in FIG. 1 , even if the wavelength λ C With wavelength λ P Close, it can also generate the pilot light P PIL The wavelength of the carrier light P does not interfere CAR '. Figure 11C The wavelength λ shown C With wavelength λ P The difference is less than Figure 4C The wavelength λ shown C With wavelength λ P The difference.

[0168] The optical wavelength division multiplexing unit 13 is provided with the optical wavelength division multiplexing unit 13 from the carrier light generating unit 11. Figure 11A The carrier light P after waveform shaping is shown CAR ', is provided from the pilot light generating unit 12 Figure 11A The pilot light P shown PIL .

[0169] The optical wavelength division multiplexing unit 13 makes the pilot light P PIL With the carrier optical P after waveform shaping CAR 'Perform wavelength division multiplexing.

[0170] like Figure 11B As shown, the optical wavelength division multiplexing unit 13 multiplexes the pilot light P PIL The carrier optical P after wavelength division multiplexing waveform shaping CAR’+PIL The signal is output to the light intensity modulation unit 14 .

[0171] The optical intensity modulation unit 14 is supplied with an RF signal (1) from the outside, and the optical wavelength division multiplexing unit 13 is supplied with a carrier light P CAR’+PIL , a bias signal B is provided from the control unit 18.

[0172] The optical intensity modulation unit 14 modulates the carrier light P by the RF signal (1). CAR’+PIL Perform light intensity modulation.

[0173] The light intensity modulation unit 14 modulates the intensity modulated light P which is the carrier light after light intensity modulation. IM The signal is output to the optical wavelength demultiplexing section 15 .

[0174] In the above embodiment 2, Figure 10 The frequency converter 1 shown is configured to include a spectrum shaping unit 19 that shapes the temporal waveform of the carrier light generated by the carrier light generating unit 11 and outputs the waveform-shaped carrier light to the optical wavelength division multiplexing unit 13. Figure 10 The frequency conversion device 1 shown is Figure 2 Compared with the frequency converter 1 shown in FIG. 1 , the accuracy of compensating for the deviation in the signal level can be improved.

[0175] Furthermore, the present disclosure allows for free combination of the various embodiments, modification of arbitrary components of the various embodiments, or omission of arbitrary components in the various embodiments.

[0176] Industrial applicability

[0177] The present disclosure is applicable to frequency conversion devices and communication devices.

[0178] Description of Reference Numerals

[0179] 1 Frequency conversion device, 2 Communication circuit, 3 Antenna, 11 Carrier light generating unit, 11a Short pulse light source, 11b Optical pulse stretching unit, 12 Pilot light generating unit, 12a Light source driving circuit, 12b Pilot light source, 13 Optical wavelength division multiplexing unit, 14 Optical intensity modulation unit, 15 Optical wavelength demultiplexing unit, 16 Optical pulse compression unit, 17 Photoelectric conversion unit, 18 Control unit, 18a Photoelectric conversion unit, 18b Bias control circuit, 19 Spectrum shaping unit.

Claims

1. A frequency conversion device, wherein: The frequency conversion device comprises: an optical wavelength division multiplexing unit for wavelength division multiplexing a pilot light having a wavelength different from that of a carrier light with the carrier light; an optical intensity modulator that modulates the optical intensity of the carrier light multiplexed by the pilot light of the optical wavelength division multiplexing unit using a signal to be frequency-converted, and outputs intensity-modulated light as the carrier light after the optical intensity modulation; an optical wavelength demultiplexing section for demultiplexing the intensity modulated light output from the optical intensity modulator into a wavelength component of the carrier light and a wavelength component of the pilot light; an optical pulse compression unit that compresses the wavelength component of the carrier light in a time direction and outputs a time-compressed pulse light as the wavelength component of the compressed carrier light; A control unit controls the light intensity modulation of the light intensity modulator based on the wavelength component of the pilot light.

2. The frequency conversion device according to claim 1, wherein: The control unit converts the wavelength component of the pilot light into an electrical signal, and controls a bias signal supplied to the light intensity modulator based on the electrical signal, thereby controlling light intensity modulation by the light intensity modulator.

3. The frequency conversion device according to claim 1, wherein: The frequency conversion device comprises: a carrier light generating unit that generates carrier light by spreading the pulse light in a time direction, and outputs the generated carrier light to the optical wavelength division multiplexing unit; as well as The pilot light generating unit generates pilot light having a wavelength different from that of the carrier light generated by the carrier light generating unit, and outputs the generated pilot light to the optical wavelength division multiplexing unit.

4. The frequency conversion device according to claim 3, wherein: The frequency converter includes a spectrum shaping unit that shapes the temporal waveform of the carrier light generated by the carrier light generating unit and outputs the waveform-shaped carrier light to the optical wavelength division multiplexing unit.

5. The frequency conversion device according to claim 1, wherein: The frequency converter includes a photoelectric converter that converts the time-compressed pulse light output from the optical pulse compressor into an electrical signal and outputs the electrical signal as a frequency-converted signal.

6. A communication device, wherein: The communication device comprises: The frequency conversion device according to claim 5; and A communication circuit outputs the electrical signal output from the photoelectric conversion section of the frequency conversion device to an antenna.

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