WO2005066707A1 - 光フーリエ変換装置及び方法 - Google Patents
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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
- G02F1/35—Non-linear optics
- G02F1/3515—All-optical modulation, gating, switching, e.g. control of a light beam by another light beam
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- 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
- G01J11/00—Measuring the characteristics of individual optical pulses or of optical pulse trains
Definitions
- the present invention relates to an optical Fourier transform apparatus and method, and particularly relates to the time waveform of an optical pulse in the form of its frequency spectrum (envelope), and the shape of Z or the frequency spectrum of the optical pulse in its form.
- the present invention relates to an optical Fourier transform apparatus and method for converting a time waveform.
- the optical Fourier transform technique is also effective in suppressing timing jitter of ultrashort pulses generated from a mode-locked laser (for example, Non-Patent Document 3). Also, there is a document describing generation of a quadratic function type optical pulse using an optical fiber amplifier having normal dispersion (for example, see Non-Patent Document 4).
- the inventor of the present invention has proposed a method of changing the time and frequency on the receiving side and completely regenerating transmission data since the pulse vector shape is invariable even if there is any linear distortion effect in the optical fiber.
- Non-distortion transmission Japanese Patent Application No. 2003-23973, “Optical transmission method and optical transmission device”, Japanese Patent Application No. 2003-181964, “ ⁇ TDM transmission method and device”
- optical pulse compression and optical function generation Japanese Patent Application No. 2003-109708, “Optical”) Application for pulse compressor and optical function generator, optical pulse compression method and optical function generation method ”).
- FIG. 1 shows a configuration example of a circuit conventionally used for performing optical Fourier transform.
- this circuit is the Pockels in an electro-optic crystal such as a LiNbO crystal.
- a phase modulator (LN phase modulator) 2 using the effect and a dispersive medium 3 having a dispersion amount D are provided. If the dispersion parameter of dispersive medium 3 is / 3 [ps 2 / km] and the length is L [km],
- phase modulator 2 As the dispersive medium 3, an optical fiber or a pair of diffraction gratings, fiber Bragg grating, or the like is used.
- the peak of the modulation characteristic of the phase modulator 2 coincides with the center position of the light pulse.
- the magnitude of the chirp applied to the norm by the LN phase modulator 2 (chirp rate K) can be obtained as follows.
- Voltage V (t) V cos applied to phase modulator 2
- Equation (1) shows that m 0
- an optical pulse having a time waveform u (t) and a frequency spectrum U ( ⁇ ) is first split into two by an optical coupler 1, and one of them is input to an LN phase modulator 2.
- the other is input to a clock signal extraction circuit 4 to extract a clock signal (sine wave signal) from the pulse train.
- the output signal is applied to the LN phase modulator 2 via the phase shifter 5 and the electric amplifier 6 to drive the LN phase modulator 2.
- the phase shifter 5 is inserted to apply the phase modulation optimally in synchronization with the optical pulse.
- the electric amplifier 6 is for driving the LN phase modulator 2.
- Patent Document 2 M. Romagnoli, P. Franco, R. Corsini, A. Schiffini, and M. Midrio, “Time-domain Fourier optics for polarization-mode dispersion compensation,” Optics Letters, vol. 24, ⁇ 17, pp. 1197—1199 (1999).
- Non-Patent Document 3 Shi A. Jiang, MEGrein, HAHaus, EPIppen, and H. Yokoyama, "Timing jitter eater for optical pulse trains, Optics Letters, vol.28, no.2, pp.78-80 (2003).
- ⁇ ltt MEFermann, VIKruglov, BCThomsen, JMDudley, and JDHarvey, "Self-simiar propagation and amplification of parabolic pulses in optical fibers," Phys. Rev. Lett. Vol.84, pp.6010-6013 (2000).
- FIG. 2 is a schematic diagram showing phase modulation (a) and magnitude of frequency shift (b) applied to an optical pulse by an LN phase modulator.
- the dotted line shows the phase modulation characteristic represented by a quadratic function and the magnitude of the frequency shift linear with time.
- the range in which the sinusoidal modulation characteristics of the LN phase modulator can be approximated by a square curve is near the center of the pulse. It will be limited.
- this is called the allowable window width of the optical Fourier transform.
- the permissible window width is narrower than the time width of the light pulse, there is a big problem that the optical Fourier transform cannot be executed accurately for the light pulse components outside the window width. .
- the present invention provides an optical Fourier transform apparatus and method capable of improving the phase modulation characteristic so as to be expressed by a quadratic function and performing optical Fourier transform over a wide time domain.
- the purpose is to provide.
- Still another object of the present invention is to provide an optical Fourier transform apparatus and method capable of performing an optical Fourier transform on an ultrahigh-speed optical pulse train whose transmission speed exceeds the limit of the processing speed of the electric circuit.
- One of the optical Fourier transform apparatuses and methods according to the present invention is to combine a signal light pulse with a parabolic control light pulse whose shape is represented by a quadratic function to obtain a single optical power medium.
- the signal light pulse is linearly phase-modulated (frequency trapped) over the entire pulse by cross-phase modulation with the control light pulse, and then the signal light pulse is converted into a dispersive medium having group velocity dispersion (secondary dispersion).
- the present invention also provides the optical Fourier transform apparatus and method as described above, wherein a parabolic control optical noise is generated by an optical fiber amplifier having normal dispersion, and the value of normal dispersion is gradually increased in the longitudinal direction.
- One of the features is to use either a decreasing dispersion fiber or an optical filter and an optical Fourier transform device whose amplitude transmission characteristics are represented by a quadratic function.
- the present invention further provides the above-described optical Fourier transform apparatus and method, wherein a low-dispersion optical power medium having a very small dispersion value is used to efficiently generate high-speed cross-phase modulation of control light and signal light.
- the wavelength of signal light and control light is zero-dispersion wave
- the wavelengths are set to be symmetrical with each other across the length (walk-off free).
- the signal light is first passed through a dispersive medium, and the shape of the signal light pulse is represented by a quadratic function.
- the frequency spectrum of the signal light pulse is obtained by multiplexing the signal light pulse with a parabolic control light pulse and linearly chirping the signal light pulse over the entire pulse in the medium of optical power by the mutual phase modulation with the control light pulse.
- another optical Fourier transform apparatus and method provides a parabolic control in which a signal light is first passed through a dispersive medium, and then the signal light pulse is represented by a quadratic function.
- the optical signal is multiplexed with the optical pulse, the optical signal is applied to the medium, and the signal optical pulse is linearly chirped over the entire pulse by cross-phase modulation with the control optical pulse.
- the signal light passes through the dispersive medium twice to completely compensate for the chirp, and to obtain a transform-limited waveform having no chirp in the output. This is one of the features.
- another optical Fourier transform apparatus and method combines a signal light pulse with a parabolic control light pulse whose shape is represented by a quadratic function, and converts the signal light pulse into a single optical power medium.
- the signal light pulse is linearly chirped over the entire pulse by cross-phase modulation with the control light pulse, and then the signal light pulse is passed through a dispersive medium, and then the signal light pulse is multiplexed with the control light pulse again. Then, the signal light pulse is linearly chirped again over the entire pulse by cross-phase modulation with the control light pulse in an optical power medium, so that the time waveform of the signal light pulse is shaped into its frequency spectrum.
- the signal light has two optical powers and one medium.
- One of the features is that the pass is completely compensated for by the rounding, and a transform-limited waveform without any chirp is obtained at the output.
- a quadratic function optical pulse generator that generates a control light pulse having a shape represented by a quadratic function or a parabola
- a multiplexer for multiplexing the signal light pulse and the control light pulse
- the input signal light pulse and control light pulse are multiplexed by the multiplexer and are incident on the optical power medium, where the signal light pulse and the control optical pulse
- the input signal light pulse is linearly chirped by phase modulation, and the signal light pulse output from the optical power medium is passed through the dispersive medium, whereby the time waveform of the input signal light pulse is changed.
- An optical Fourier transform device for converting into a frequency spectrum shape is provided.
- a quadratic function optical pulse generator that generates a control light pulse having a shape represented by a quadratic function or a parabola
- a multiplexer for multiplexing the signal light pulse and the control light pulse
- the input signal light pulse is passed through the dispersive medium, and the signal light pulse output from the dispersive medium and the control light pulse are multiplexed by the multiplexer to be incident on the optical power medium. Then, in the optical power medium, the signal light pulses output from the dispersive medium force are linearly changed by the mutual phase modulation of the signal light pulses and the control light pulses.
- the optical Fourier transform apparatus that converts the shape of the frequency spectrum of the input signal light pulse into its time waveform by providing the input signal light pulse is provided.
- optical Fourier transform apparatus and method of the present invention a parabolic optical pulse is used as control light, and a linear chirp can be applied to the signal light by cross-phase modulation with the signal light. , More accurate optical Fourier transform can be realized. Further, since the optical Fourier transform apparatus and method of the present invention do not require signal processing by an electric circuit, it is possible to execute optical Fourier transform even on a high-speed signal pulse train exceeding the limit of the processing speed by electricity. . Therefore, various applications of the optical Fourier transform limited by the performance of the conventional optical Fourier transform apparatus can be realized by the optical Fourier transform apparatus and method of the present invention.
- FIG. 1 is a diagram showing a configuration of a conventional optical Fourier transform device.
- FIG. 2 is a schematic diagram showing magnitudes of phase modulation and frequency shift applied to an optical pulse by an LN phase modulator.
- the dotted line indicates the ideal phase modulation characteristics and the magnitude of the frequency shift.
- FIG. 3 is a diagram showing a configuration of an optical Fourier transform device according to a first embodiment of the present invention.
- FIG. 4 is a diagram showing a configuration (first embodiment) of a quadratic function optical noise generator 7 in FIG.
- FIG. 5 is a diagram showing a configuration (second embodiment) of the quadratic function type optical noise generator 7 in FIG. 3.
- FIG. 6 is a diagram showing a configuration (third embodiment) of a quadratic function type optical noise generator 7 in FIG. 3.
- FIG. 7 is a schematic diagram showing a state where a linear cap is applied to signal light by cross-phase modulation between control light and signal light.
- FIG. 8 The change in the longitudinal direction of the dispersion value of the normal dispersion decreasing fiber 16 in FIG. 5 (a), and the use of the quadratic function type optical noise generator 7 when the normal dispersion decreasing fiber is used in FIG.
- FIG. 9 is a diagram showing a time waveform (b) of a control light pulse obtained by output.
- FIG. 9 is a diagram showing a time waveform and a frequency chirp of the signal light that is split by the optical filter 11 after propagating through the optical power medium 10 in FIG. 3.
- the thin solid line shows the theoretical value of the frequency chirp applied to the signal light
- the thin dotted line shows the frequency chirp applied to the signal light by the conventional LN phase modulator.
- FIG. 10 is a diagram showing a time waveform of signal light at an output of the dispersive medium 12 in FIG. 3.
- the thin solid line shows the result of the optical Fourier transform when an ideal linear curve is applied to the signal light with the optical power medium 10
- the thin dotted line shows the result of the signal light using the conventional LN type optical modulator. 4 shows a result of optical Fourier transform when a loop is applied.
- FIG. 11 is a diagram showing a configuration of a second embodiment of the optical Fourier transform device of the present invention.
- FIG. 12 is a diagram showing a configuration of an optical Fourier transform device according to a third embodiment of the present invention.
- FIG. 13 is a diagram showing a configuration of an optical Fourier transform device according to a fourth embodiment of the present invention.
- FIG. 3 shows a configuration diagram of the optical Fourier transform device according to the first embodiment of the present invention.
- the optical Fourier transform device includes an optical coupler 1, a clock signal extraction circuit 4, a quadratic function optical pulse generator 7, an optical delay element 8, a multiplexer 9, an optical power medium 10, an optical filter 11, and , A dispersive medium 12.
- the optical power medium 10 is a medium having a third-order nonlinear refractive index, for example, a single mode optical fiber, a photonic crystal fiber, a semiconductor optical amplifier, an erbium-doped optical fiber amplifier, or an organic nonlinear material.
- the dispersive medium 12 is, for example, a single mode optical fiber or a pair of diffraction gratings having a group velocity dispersion characteristic in which a zero dispersion region exists near a wavelength band of 1.3 ⁇ m, a fiber Bragg grating, or the like. Can be used.
- the clock signal extraction circuit 4 receives the signal light pulse branched by the optical coupler 1 and extracts a clock signal based on the signal light pulse.
- solid lines indicate optical pulses (optical signals), and dotted lines indicate electrical signals. The following The same applies to the diagrams showing the configuration of the one-Lie transform apparatus and the quadratic function type optical pulse generator.
- the quadratic function type optical pulse generator 7 generates a control optical pulse according to the clock signal output from the clock signal extraction circuit.
- the optical delay element 8 gives an appropriate time delay so that the center time position of the control light pulse coincides with the timing of the signal light pulse.
- the optical filter 11 is a filter for splitting the signal light from the control light.
- the quadratic function optical pulse generator 7 is a device that generates a pulse having a parabolic waveform (hereinafter, also referred to as a control light pulse or a quadratic function light pulse). It can be realized in the form.
- the first mode uses an optical fiber amplifier having normal dispersion (for example, see Non-Patent Document 4).
- FIG. 4 shows a configuration of a quadratic function type optical pulse generator according to the first embodiment.
- the quadratic function type optical pulse generator 7 of the first embodiment has an optical pulse transmitter 13 and a normal dispersion optical fiber amplifier 14.
- the optical noise transmitter 13 includes, for example, a mode-locked laser, an EA (Electro-Absorption) modulator, or an LN modulator driven by a clock extracted from signal light power using a clock signal extraction circuit 4. It is made by combination.
- the pulse When an optical pulse output from the optical pulse transmitter 13 is input to the normal dispersion optical fiber amplifier 14, the pulse is linearly chirped over the entire waveform by normal dispersion and nonlinear optical effects, and at the same time, the pulse shape is shaped parabolically. .
- the second mode uses an optical fiber having a normal dispersion and the magnitude of the dispersion value gradually decreases in the longitudinal direction (see, for example, Japanese Patent Application No. 2003-387563 “Optical pulse generation method and optical fiber”). Pulse compression method ”).
- FIG. 5 shows a configuration of a quadratic function type optical pulse generator 7 according to the second embodiment.
- the optical pulse output from the optical pulse transmitter 13 driven by the clock signal is amplified by the optical amplifier 15 and input to the normal dispersion decreasing fiber 16, a parabolic pulse is obtained at the output.
- a parabolic pulse is obtained at the output.
- the quadratic function type optical pulse generator 7 includes an optical pulse transmitter 13, an optical amplifier 15, and a normal dispersion decreasing fiber 16.
- the optical noise transmitter 13 is, for example, a mode-locked fiber laser. Alternatively, a mode-locked semiconductor laser can be used. Considering the use in the optical communication wavelength band, a particularly suitable wavelength is 1. Band power.
- the wavelength and the waveform of the generated optical pulse are not limited to these, and any arbitrary one can be used.
- the optical amplifier 15 is used to generate a nonlinear optical effect (self-phase modulation effect) in the normal dispersion decreasing fiber 16.
- the output from the optical amplifier 15 is a non-linear pulse.
- the non-linear optical pulse refers to, for example, an optical pulse having a power required to obtain a nonlinear optical effect in the normal dispersion decreasing fiber 16.
- the normal dispersion decreasing fiber 16 is an optical fiber having a normal dispersion value and the magnitude of the dispersion value decreases in the longitudinal direction.
- the normal dispersion decreasing fiber 16 one fiber in which the magnitude of the dispersion value changes continuously can be used.
- the magnitude of the dispersion value decreases means that the absolute value of the dispersion value decreases, and such a normal dispersion fiber is referred to as a normal dispersion decreasing fiber. Called fiber.
- the normal dispersion decreasing fiber 16 can be realized, for example, by changing the core diameter continuously in the longitudinal direction in a normal optical fiber made of quartz glass.
- the normal dispersion decreasing fiber 16 has a constant dispersion value, or a cascade connection of several types of fibers that change linearly in the longitudinal direction or that continuously changes the dispersion value, thereby reducing the dispersion value of the fiber.
- the continuous decrease of may be discretely approximated.
- a function D (z) representing a change in dispersion value along the longitudinal direction of the normal dispersion decreasing fiber 16 is reduced so as to decrease with distance (longitudinal coordinate) z.
- ⁇ represents the rate of decrease in the magnitude of the normal variance.
- FIG. 5B shows an example of a change in the dispersion value of the normal dispersion-decreasing fiber 16.
- the dotted line in the figure represents the fiber 16 whose dispersion value changes continuously, and the solid line is an example approximated by cascading three types of fibers whose dispersion value changes linearly in the longitudinal direction.
- the force using three types of fibers is not limited to this, and an appropriate number of fibers can be used.
- a parabolic optical filter whose amplitude transmission characteristic is expressed by a quadratic function is used to shape the spectral shape of an optical pulse into a parabolic shape, and a conventional optical Fourier transform device (for example, as shown in FIG. 1)
- This device converts the parabolic spectrum shape into a parabolic optical pulse waveform by the device.
- FIG. 6 shows a configuration of a quadratic function type optical pulse generator 7 according to the third embodiment.
- the quadratic function type optical pulse generator 7 of the third embodiment includes an optical pulse transmitter 13, a parabolic optical filter 17, and an optical Fourier transform device 18.
- an optical pulse output from an optical pulse transmitter 13 driven by a clock signal is input to a parabolic optical filter 17 and its spectral shape is shaped into a parabolic shape.
- a quadratic optical pulse whose time waveform is parabolic is obtained at the output.
- the optical Fourier transform device 18 uses the same one as the conventional one.
- the characteristics of the optical Fourier transform depend on the relationship between the pulse width having a parabolic spectral shape and the characteristics of the phase modulator. Therefore, in the phase modulator used in the conventional optical Fourier transformer 18, if there is a pulse that has passed through the parabolic optical filter 17 within a time range where the modulation characteristic can be approximated by a quadratic function, the output will be a quadratic function type. The control light noise is obtained.
- a signal light pulse train is branched by an optical coupler 1, and one of them is connected to a clock signal extraction circuit 4 to extract a clock signal of a noise train.
- a signal light pulse (wavelength ⁇ ) having a time waveform u (t), a frequency spectrum U ( ⁇ ) and a parabolic control light pulse (wavelength ⁇ ) output from the quadratic function type optical pulse generator 7 are The light is multiplexed by the multiplexer 9 and input to the optical power-medium 10. At this time, an appropriate time delay is given by the optical delay element 8 so that the center time position of the control light pulse coincides with the timing of the signal light pulse.
- the time waveform u (t) of the signal light pulse and its frequency spectrum U ( ⁇ ) are [0044] Girl 4
- the instantaneous frequency of the signal light is modulated by the cross-phase modulation of the signal light and the control light in accordance with the time change of the control light intensity.
- the signal light intensity is sufficiently smaller than the control light, and the self-phase modulation due to the change in the intensity of the signal light itself can be ignored.
- I (t) is the intensity of control light per unit area
- n is a constant called the Kerr coefficient
- the quadratic function type optical pulse which is the control light has a time waveform u (t) given by the following equation.
- ⁇ indicates the time width from the center of the quadratic function type optical noise to the base. For example, ⁇
- Equation (5) is an equation for the pulse amplitude, and the power is expressed in the form of the square of time t. Therefore, the trap generated in the signal light by the cross-phase modulation is given by Eqs. (4) and (5).
- the phase modulation characteristic of the optical power medium 10 depends on the waveform of the control light as shown in Expression (4), but when the intensity of the control light is parabolic as in the present embodiment, ,
- FIG. 7 schematically shows a state in which a linear cap is applied to each optical pulse constituting a signal light pulse train by cross-phase modulation with a quadratic function light pulse train.
- the repetition frequency of the signal light and control light pulse train is set to the inverse of the time width 2T of the quadratic function light pulse.
- FIG. 7 shows the time waveforms of the signal light (solid line) and the control light (dotted line), and the lower part shows the frequency shift applied to the signal light. As shown in the figure, assuming that the time width from the center of the control light to the tail is T, the signal light has a linear change over a 2T time width.
- the magnitude of the chirp rate ⁇ depends on the peak power p and light power of the control light pulse.
- the wavelength difference I between the signal light and the control light is I. It is desirable that the walk-off due to the group velocity mismatch caused by ⁇ - ⁇ I be small (the above sc
- the walk-off refers to a group delay generated between the control light and the signal light due to a difference in group velocity between the two.
- ⁇ and ⁇ are the same as those of the optical power medium 10 so that the signal light and the control light receive the same time delay in the optical power medium 10 using the optical power medium 10 having a very small dispersion value.
- the wavelengths are mutually symmetrical with respect to the zero dispersion wavelength; I and / or I may be set. For example, such; I can be set by the optical pulse transmitter 13 of the quadratic optical pulse generator 7.
- Time waveform u (t) of the signal light pulse after a linear trap is applied by the optical power medium 10.
- the signal light After passing through the optical power medium 10, the signal light is demultiplexed from the control light by the optical filter 11 and input to the dispersive medium 12.
- the time waveform v (t) of the signal light pulse after passing through the dispersive medium 12 is
- the signal light having a different frequency assigned to each time position in the optical power medium 10 is given a different time delay according to the frequency due to the group velocity dispersion in the dispersive medium 12. .
- each frequency component of the signal light pulse is separated on the time axis.
- D l / K
- a parabolic pulse obtained by a quadratic function type optical pulse generator 7 having a configuration as shown in FIG. 5 is used as the control light.
- the control light energy is 20 pJ
- FIG. 8 shows a change (a) in the longitudinal direction of the dispersion value of the normal dispersion decreasing fiber 16 and a waveform (b) of the control light pulse at the output.
- FIG. 9 is a diagram showing the time waveform and frequency chirp of the signal light that has been split by the optical filter 11 after propagating through the optical power medium 10.
- a thin solid line is applied to the signal light.
- the dashed line indicates the frequency trap applied to the signal light by the conventional LN phase modulator.
- the bold solid lines represent the power and the cap in the present numerical calculation example.
- the arrows and ellipses in the figure indicate that the left axis is a power graph and the right axis is a chirp graph.
- FIG. 9 show the signal light having a pulse width lOps having a Gaussian shape and the above-described control light obtained at the output of the normal dispersion decreasing fiber 16.
- FIG. 6 shows a time waveform and a frequency chirp of signal light that is multiplexed by a multiplexer 9 and propagated through an optical power medium 10 and then demultiplexed from control light by an optical filter 11.
- the wavelength interval between the signal light and the control light is 2 Onm.
- a dispersion-shifted fiber having a dispersion value of -0.2 ps / nm / km, a nonlinear coefficient of 3 ⁇ SSW-km- 1 , and a length of 1450 m is used as the optical power medium 10.
- FIG. 10 shows a waveform (thick line) of the signal light after the captured signal light is input to the dispersive medium 12 and propagated.
- the thin solid line indicates that the signal light u (t) calculated using Equation (10) after the optical Fourier transform is calculated using Equation (10), assuming that the chirp is completely linear (a linear chirp was applied to the signal light with a medium of light power 10).
- Waveform v (t) the thin dotted line shows the results when optical Fourier transform was performed using a conventional LN phase modulator (when a LN-type optical modulator was used and a chip was applied to the signal light). It is.
- the Fourier transform image is distorted, but by using the optical Fourier transform device according to the present embodiment, no distortion occurs in the Fourier transform image, and It can be seen that the pulse width is the same as the pulse width when the cap is assumed to be perfectly linear.
- FIG. 11 shows a configuration diagram of an optical Fourier transform device according to the second embodiment of the present invention.
- the dispersive medium 12 is located before the multiplexer 9 in the present embodiment.
- Other configurations are the same as those described above, and a description thereof will be omitted.
- the quadratic function light pulse generator 7 can have any one of the configurations shown in FIGS. 4 and 6 as in the first embodiment.
- a signal light pulse (wavelength; I) having a time waveform u (t) and a frequency spectrum U ( ⁇ ) branched by the optical coupler 1 is first input to the dispersive medium 12.
- the frequency spectrum U ( ⁇ ) of the signal light pulse at the output of the dispersive medium 12 is
- the signal light pulse and the parabolic control light pulse (wavelength ⁇ ) output from the quadratic function light pulse generator 7 are multiplexed by the multiplexer 9 and input to the optical power medium 10.
- an appropriate time delay is given to the control light pulse by the optical delay element 8 so that the center time position of the control light pulse coincides with the timing of the signal light pulse.
- a linear pickup ⁇ (formula (6)) is applied to the signal light by cross-phase modulation with the control light.
- the signal light and the control light are split by the optical filter 11.
- the frequency stutter of the signal light V (co) at the output of the optical filter 11 is given by convolution with U ( ⁇ ),
- FIG. 12 shows a configuration diagram of an optical Fourier transform device according to the third embodiment of the present invention.
- the optical Fourier transform device according to the third embodiment includes an optical coupler 1, a clock signal extracting circuit 4, a quadratic function type optical pulse generator 7, an optical delay element 8, a multiplexer 9, an optical power medium 10, an optical It comprises a filter 11, a dispersive medium 12, and optical circulators 20 and 20 '.
- the signal light split by the optical coupler 1 is first input to the port 20 a of the optical circulator 20.
- the port 20a is connected to the port 20'a via the port 20b, the dispersive medium 12, and the port 20'b of the optical circuit 20 '.
- the port 20'a and the port 20'c of the optical circulator 20 ' are connected in a loop through a multiplexer 9, an optical power medium 10, and an optical filter 11.
- the signal light demultiplexed by the optical filter 11 is applied to port 20'c and port 20 ' After passing through the dispersive medium 12 again through b, the light is output from the port 20c through the port 20b of the optical circulator 20.
- One input of the multiplexer 9 receives the signal light from the port 20'a of the optical circulator 20 ', and the other input is generated by the quadratic optical pulse generator 7 and the optical delay element 8.
- the control light is incident.
- the optical delay element 8 is used to give an appropriate time delay to the control light so that the center time position of the control light pulse coincides with the timing of the signal light pulse in the optical power medium 10.
- the time waveform u— (t) of the signal light pulse at the output of the dispersive medium 12 is expressed by the following equation by convolution using the time waveform u (t) of the input signal light pulse.
- the signal light is input to the optical Kerr medium 10, and a linear trap ⁇ ⁇ (Equation (6)) is applied to the signal light by mutual phase modulation with the control light. .
- the time waveform u (t) of the signal light pulse at the output of the optical power-medium 10 is calculated using u (t).
- the signal light is demultiplexed from the control light by the optical filter 11 and then input to the dispersive medium 12 again.
- the time waveform v (t) of the signal light pulse uses u (t).
- the signal light passes twice through the dispersive medium 12 to completely compensate for the chirp, and unlike the first embodiment, a transform-limited waveform without any chirp is obtained at the output. warn.
- FIG. 13 shows the configuration of the optical Fourier transform device according to the fourth embodiment of the present invention.
- the optical Fourier transform device according to the fourth embodiment includes an optical coupler 1, a clock signal extraction circuit 4, a quadratic optical pulse generator 7, optical delay elements 8 and 8 ', multiplexers 9 and 9', It comprises a force medium 10, an optical filter 11, a dispersive medium 12, a duplexer 19, and optical circulators 20 and 20 '.
- Components having the same reference numerals as those of the optical Fourier transform device shown in FIG. 3 are the same as those described above, and thus description thereof is omitted.
- the signal light is first multiplexed by the multiplexer 9 with the control light generated by the quadratic function type optical pulse generator 7 and the optical delay element 8.
- the output of the multiplexer 9 separates the control light and the signal light through the ports 20a and 20b of the optical circulator 20, the optical power medium 10, and the ports 20'b and 20'a of the optical circulator 20 '.
- the demultiplexer 19 demultiplexes the control light and the signal light.
- One output (signal light) of the demultiplexer 19 passes through the dispersive medium 12, and the other output (control light) passes through the optical delay element 8 ′.
- the control light and the signal light are multiplexed again in the multiplexer 9 '.
- the output of the multiplexer 9 ' is connected to the optical filter 11 via the port 20'c and the port 20'b of the optical circulator 20', the optical power medium 10, the port 20b and the port 20c of the optical circulator 20.
- the optical filter 11 separates the signal light from the control light.
- the optical delay elements 8 and 8 ' are used to give an appropriate time delay to the control light so that the center time position of the control light pulse coincides with the timing of the signal light pulse in the optical power medium 10.
- the time waveform u (t) after the signal light multiplexed with the control light and input to the optical power medium 10 undergoes a linear chirp in the optical power medium 10 is the original signal light pulse. Is expressed by the following equation using the time waveform u (t).
- the signal light passes twice through the optical power medium 10 to completely compensate for the chirp.
- a chirpless waveform and a transform-limited waveform are generated at the output. Note that you can get.
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EP04807872.9A EP1705516B1 (en) | 2004-01-05 | 2004-12-27 | Optical fourier transform device and method |
US10/584,932 US7352504B2 (en) | 2004-01-05 | 2004-12-27 | Optical fourier transform device and method |
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JP2004000464A JP4471666B2 (ja) | 2004-01-05 | 2004-01-05 | 光フーリエ変換装置及び方法 |
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EP (1) | EP1705516B1 (ja) |
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JP4471572B2 (ja) * | 2003-01-31 | 2010-06-02 | 独立行政法人科学技術振興機構 | 光伝送方法 |
JP4459547B2 (ja) * | 2003-04-15 | 2010-04-28 | 独立行政法人科学技術振興機構 | 光パルス圧縮器および光関数発生器、光パルス圧縮方法および光関数発生方法 |
JP4495415B2 (ja) * | 2003-06-26 | 2010-07-07 | 独立行政法人科学技術振興機構 | Otdm伝送方法及び装置 |
EP1866616B1 (en) | 2005-04-05 | 2013-01-16 | The Board Of Trustees Of The Leland Stanford Junior University | Optical image processing using minimum phase functions |
JP5400282B2 (ja) * | 2007-06-28 | 2014-01-29 | 古河電気工業株式会社 | パルス増幅器及びこれを用いたパルス光源 |
EP2344923A4 (en) | 2008-10-14 | 2017-05-03 | Cornell University | Apparatus for imparting phase shift to input waveform |
US8532398B2 (en) * | 2010-03-26 | 2013-09-10 | General Electric Company | Methods and apparatus for optical segmentation of biological samples |
US9366937B2 (en) * | 2012-01-13 | 2016-06-14 | Sumitomo Osaka Cement Co., Ltd. | Optical pulse-generator |
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US8903245B2 (en) * | 2012-04-30 | 2014-12-02 | I-Shou University | Optical radiation signal generating device and tranceiving system, and method of generating an optical radiation signal |
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US11287721B2 (en) | 2018-05-09 | 2022-03-29 | Sharif University Of Technology | Reconfigurable optical signal processing |
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US11444690B2 (en) * | 2019-07-17 | 2022-09-13 | Lawrence Livermore National Security, Llc | Timing measurement apparatus |
US11209714B2 (en) | 2019-07-17 | 2021-12-28 | Lawrence Livermore National Security, Llc | Radio frequency passband signal generation using photonics |
US11159241B2 (en) | 2019-07-18 | 2021-10-26 | Lawrence Livermore National Security, Llc | High power handling digitizer using photonics |
US11184087B2 (en) | 2019-08-08 | 2021-11-23 | Lawrence Livermore National Security, Llc | Optical encoder devices and systems |
CN111966960B (zh) * | 2020-07-21 | 2023-12-26 | 北京邮电大学 | 全光短时傅里叶变换系统及方法 |
CN113098594B (zh) * | 2021-03-22 | 2022-03-08 | 杭州电子科技大学 | 具有复数值输出的光学实时傅里叶变换的装置及方法 |
CN114967116B (zh) * | 2022-03-06 | 2024-06-25 | 天津理工大学 | 时空相干涡旋在色散介质中的传输模型及其相干性调控方法 |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH05265057A (ja) * | 1992-03-23 | 1993-10-15 | Nippon Telegr & Teleph Corp <Ntt> | 全光型タイムスロット変換回路 |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6744552B2 (en) * | 1998-04-02 | 2004-06-01 | Michael Scalora | Photonic signal frequency up and down-conversion using a photonic band gap structure |
US6650466B1 (en) * | 1999-08-27 | 2003-11-18 | Frank Wise | High-energy pulse compression using phase shifts produced by the cascade quadriatic nonlinearity |
-
2004
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Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH05265057A (ja) * | 1992-03-23 | 1993-10-15 | Nippon Telegr & Teleph Corp <Ntt> | 全光型タイムスロット変換回路 |
Non-Patent Citations (14)
Title |
---|
ANDERSON D. ET AL.: "Wave-braking-free pulses in nonlinear-optical fiber.", J. OPT.SOC.AM., vol. 10, no. 7, 1993, pages 1185 - 1190, XP002989821 * |
FERMANN M.E. ET AL.: "Self-similar propagation and amplification of parabolic", PHYSICAL REVIEW LETTERS., vol. 84, no. 26, 2000, pages 6010 - 6013, XP002987597 * |
HARVEY J. D. ET AL.: "Analytical solutions of the nonlinear Schrodinger equation with gain", LEOS, vol. 1, 2002, pages 319 - 320, XP010620540, DOI: doi:10.1109/LEOS.2002.1134058 |
HIROOKA T. ET AL.: "Parabolic pulse generation by use of a dispersion-decreasing f", OPTICS LETTERS., vol. 29, no. 5, March 2004 (2004-03-01), pages 498 - 500, XP002987598 * |
KOLNER B.H. ET AL.: "Space-time duality and the theory of temporal imaging.", IEEE JOURNAL OF QUANTUM ELECTRONICS., vol. 30, no. 8, 1994, pages 1951 - 1963, XP002980366 * |
KRUGLOVV. I. ET AL.: "Self-similar propagation of high-power parabolic pulses in optical fiber amplifiers", OPTICS LETTERS, vol. 25, no. 24, pages 1753 - 1755, XP002474446, DOI: doi:10.1364/OL.25.001753 |
L.A.JIANG ET AL.: "Timing jitter eater for optical pulse trains", OPTICS LETTERS, vol. 28, no. 2, 2003, pages 78 - 80, XP002980090, DOI: doi:10.1364/OL.28.000078 |
L.F.MOLLENAUER; C.XU: "Time-lens timing-jitter compensator in ultra-long haul DWDM dispersion managed soliton transmissions", CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO) 2002, PAPER CPDB1, 2002 |
M.E.FERMANN ET AL.: "Self-simiar propagation and amplification of parabolic pulses in optical fibers", PHYS.REV.LETT., vol. 84, 2000, pages 6010 - 6013, XP002737934, DOI: doi:http://dx.doi.org/10.1103/PhysRevLett.84.6010 |
M.ROMAGNOLI ET AL.: "Time-domain Fourier Optics for polarization-mode dispersion compensation", OPTICS LETTERS, vol. 24, no. 17, 1999, pages 1197 - 1199, XP002251101, DOI: doi:10.1364/OL.24.001197 |
MOURADIAN L. ET AL.: "Characterization of optical signals in fiber-optic Fourier converter", PROCEEDINGS OF THE SPIE, vol. 3418, 1998, pages 78 - 85, XP002474445, DOI: doi:10.1117/12.326641 |
MOURADIAN L. ET AL.: "Spectro-temporal imaging of femtosecond events", IEEE JOURNAL OF QUANTUM ELECTRONIC, vol. 36, no. 7, 2000, pages 795 - 801, XP011449724, DOI: doi:10.1109/3.848351 |
MOURADIAN L. KH. ET AL.: "Spectro-temporal imaginf of femtosecond events.", IEEE JOURNAL OF QUANTUM ELECTRONICS., vol. 36, no. 7, 2000, pages 795 - 801, XP002987596 * |
See also references of EP1705516A4 * |
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Publication number | Publication date |
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EP1705516A1 (en) | 2006-09-27 |
JP2005195751A (ja) | 2005-07-21 |
EP1705516B1 (en) | 2015-06-03 |
US7352504B2 (en) | 2008-04-01 |
JP4471666B2 (ja) | 2010-06-02 |
US20070273958A1 (en) | 2007-11-29 |
EP1705516A4 (en) | 2008-05-14 |
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