JPH08159867A - Light-waveform measuring apparatus - Google Patents

Abstract

PURPOSE: To provide a light-waveform measuring apparatus which carriers out a low noise sample measurement. CONSTITUTION: After the intensity is modulated by a light-modulating means 140, the pulse light 101 to be measured is made incident on a light deflecting means 104 and swept for a prescribed duration. The intensity of the pulse light to be measured is lowered during the time except the sweeping time by modulation of the light-modulating means 140. Consequently, the intensity of the pulse light which is incident on a light detecting means 108 is lowered during the time except the sweeping time. Scarce light to be measured can be transmitted through a slit during the period except the sweeping time by sufficiently lowering the light to be measured during the time except sweeping time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for measuring an optical waveform at high speed by utilizing light deflection.

[0002]

2. Description of the Related Art Conventionally, a streak camera has been known as an apparatus for measuring an optical waveform at high speed. This is to reproduce an optical waveform by deflecting electrons generated by photoelectrically converting the light to be measured incident on the photocathode and making the electrons incident on the phosphor screen while sweeping linearly to obtain an image thereof. But,
Since the sensitivity of the photocathode is only up to about 1.6 μm, this streak camera cannot measure light with a wavelength longer than this.

As an optical waveform measuring device for infrared light, a solid streak camera using the electro-optical effect of a nonlinear crystal has been proposed. This is a paper by CLMIreland, "THE USE OF A LiNbO3 DEFLECTOR IN A ~ 100ps RESO
LUTION STREAK CAMERA "(OPTICSCOMMUNICATIONS, Vol27,
1978 pp 459-462).

FIG. 10 is a block diagram of a solid streak tube which is the heart of the solid streak camera. The pulsed light 101 to be measured from the light source is converted into linearly polarized light by the polarizer 102, and converted into a beam having an appropriate diameter by the aperture 103. After that, the pulsed light to be measured is deflected by the light deflection element 104 and swept in one direction. The light under measurement passes through the Fourier transform lens 105 and the image sensor 106.
A Fourier transform image is formed on the top.

On the other hand, the trigger pulse 120 is input to the controller 121, and the sweep pulse 122 and the read pulse 125 are output at the timing corresponding to the pulsed light to be measured.

The high voltage circuit 123 applies a sweep voltage as shown in FIG. 11A in response to the sweep pulse 122 to the optical deflection element 1.
04 is applied to sweep the measured light. The pulse light to be measured having a time waveform as shown in FIG.
When incident on, the temporal intensity change of the measured light becomes a spatial intensity change as shown in FIG. 11C due to the sweep. By detecting the spatial intensity change with the image sensor 106, the temporal intensity change of the pulse light to be measured can be known. The image sensor 106 outputs a detection signal in response to the read pulse 125, and the waveform of the measured light is displayed on a display (not shown) based on this signal.

This solid streak camera has the following problems. (1) Low sensitivity. This is because the image sensor used is a solid-state element and does not have an amplifying action like an electron tube. (2) Since the ramp portion of the sweep voltage is not a perfect straight line, the output waveform is distorted and the linearity is not good. (3) The measurement range is narrow because only phenomena within the sweep time can be measured.

In order to solve the above-mentioned problems, of the light beams deflected by the light deflection element and condensed by the lens, the light passing through the slit is sampled and measured by the detector, and the optical waveform is reproduced. The device is fair 6-17
819.

FIG. 12 is a block diagram of this optical waveform measuring apparatus. A sweep voltage is applied to the optical deflector 104 at the moment when the pulsed light 101 to be measured enters the optical deflector 104, whereby the measured light is deflected and swept in one direction. The measured light 101 forms a Fourier transform image on the slit plate 107 via the Fourier transform lens 105. On the slit plate 107, the temporal intensity change of the pulsed light 101 to be measured appears as a spatial intensity change. Light to be measured 1 with a part of spatial intensity change cut out by a slit
01 is photoelectrically converted by the photodetector 108, and a signal having a level corresponding to the light intensity is output.

FIG. 13 is a diagram for explaining the sampling method of this optical waveform measuring apparatus. The sweep voltage is 10
It is applied with a delay time shifted for each 1 pulse,
Thereby, sampling is performed. The time waveform of the measured light 101 can be reproduced based on the measured light intensity and the delay time information obtained for each pulse of the measured light.

The optical waveform measurement by such a sampling method has the following features. (1) The sensitivity can be increased by using a phototube or a photoelectron multiplier as a photodetector. The sensitivity can also be increased by using a lock-in amplifier or the like. (2) The measurement range does not depend on the sweep time. (3) No linearity and good linearity. (4) It is not necessary to correct the time axis (the delay time becomes the time axis).

[0012]

The above-mentioned optical waveform measuring device has a problem that it becomes difficult to measure the waveform when the pulse width of the measured waveform becomes extremely larger than the sweep time. FIG. 14 is a waveform diagram for explaining this.
When the sweep voltage as shown in (b) is applied to the optical deflector for the pulsed light to be measured as shown in (a), the spatial intensity change on the slit of the pulsed light to be measured becomes as shown in (c). . This is a result of the accumulation of the light intensity of the pulsed light under measurement over the response time of the photodetector.
That is, outside the sweep time, the light to be measured is radiated to a certain part on the side of the slit, but this light to be measured has a spatial spread and the intensity distribution spreads over the slit. Since the measured light continues to be radiated outside the sweep time, the intensity of the measured light that passes through the slit cumulatively increases outside the sweep time as the pulse width of the measured pulse light becomes larger than the sweep time. growing. In this case, in addition to the measured light that passes through the slit during the sweep time, the measured light outside the sweep time also enters during the response time of the photodetector. As a result, there is a problem that the measured light intensity including a large noise component is detected.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an optical waveform measuring apparatus for performing sampling measurement with less noise.

[0014]

In order to solve the above problems, the optical waveform measuring apparatus according to the present invention comprises: (a) a first driving electric power applied with the intensity of the pulse light to be measured which is repeatedly incident. An optical modulator that modulates according to the magnitude of the signal,
(B) Optical deflecting means for sweeping the measured pulsed light by deflecting the measured pulsed light emitted from the light modulating means at an angle according to the magnitude of the applied second drive electric signal,
(C) light-shielding means having a non-translucent light-incident surface on which a light-transmissive window is formed, and transmitting the pulsed light under measurement deflected at a predetermined angle by the light deflecting means through the window. (D) The photodetection means for receiving the measured pulsed light transmitted through the light shielding means and outputting an electric signal of a level corresponding to the light intensity, and (e) the first drive electric signal for the optical modulation means. The measurement light is applied with a different timing for each pulse, the second drive electric signal is applied to the light deflecting means with a different timing for each pulse of the light under measurement, and the application timing of the second drive electric signal is applied. The optical modulation is provided with drive control means for outputting information on the deviation, and (f) information processing means for obtaining the waveform of the pulse light to be measured based on the information on the deviation of the application timing and the output signal of the light detecting means. The means emits from this light modulating means And the intensity in the outer sweep time of the measured pulse light is reduced from the previous incident on the light modulation means that.

The light modulating means is applied with a polarizer for converting the pulsed light to be measured into linearly polarized light in a predetermined direction and a first drive electric signal, and emits light from the polarizer according to the magnitude of this signal. The electro-optical modulator includes an electro-optical crystal that rotates the polarization direction of the measurement pulse light, and an analyzer that receives the emitted light from the electro-optical crystal and transmits linearly polarized light in a predetermined direction. The electro-optical deflector is preferably made of one or more electro-optical crystals to which the second drive electric signal is applied. Further, the drive control means applies a signal whose magnitude monotonously changes corresponding to the time for rotating the polarization direction of the pulse light under measurement as the first drive electric signal to the light modulating means, so that the pulse light under measurement is measured. It is preferable to apply a signal whose magnitude monotonously changes in accordance with the sweep time of 2) as the second drive electric signal to the optical deflecting means.

The optical waveform measuring device of the present invention comprises a spectroscopic means for emitting the pulsed light to be measured emitted from the optical deflecting means in different directions for each wavelength on a plane different from the plane on which the pulsed light to be measured is deflected. Further, the optical waveform of the pulsed light to be measured may be measured for each wavelength. This optical waveform measuring device is provided with a pinhole plate having a pinhole as a window portion as a light shielding means, and transmits the light of a desired wavelength among the measured pulsed light emitted from the spectroscopic means by the movement of the pinhole plate. May be Further, as the light shielding means, a slit plate having a slit as a window portion for transmitting all the measured pulsed light emitted from the spectroscopic means in different directions for each wavelength, and as the light detecting means, receiving the measured pulsed light transmitted through this slit plate The image waveform of the pulsed light to be measured may be measured for each wavelength based on the light receiving position on the image sensor.

Further, in the optical waveform measuring apparatus of the present invention, the light detecting means receives a plurality of pulsed light to be measured emitted from the light shielding means in different directions according to the traveling directions of the plurality of pulsed light to be measured, The pulsed light to be measured may be detected.

[0018]

The pulsed light to be measured which has entered the optical waveform measuring device of the present invention is intensity-modulated by the optical modulator and then enters the optical deflector where it is swept for a predetermined time. The pulsed light to be measured is applied to the light incident surface of the light shielding means while being swept. As a result, the temporal intensity change of the pulse light to be measured becomes a spatial intensity change on the light incident surface of the light shielding means. Only the light that has passed through the window of the light shielding means of the pulsed light to be measured is incident on the photodetector,
The light intensity is measured. Thereby, a part of the spatial intensity change on the light incident surface is cut out by the window and measured.

The voltage control means applies a drive voltage to the light deflecting means by shifting the timing for each pulse of the measured light. In this way, by measuring the intensity of the light transmitted through the window for each measured pulse light while shifting the sweep timing for each pulse of the measured light, the temporal intensity change of the measured pulse light is sampled and measured. To be done. The information processing means processes the information on the drive voltage application timing deviation and the output of the photodetector to reproduce the time waveform (temporal intensity change) of the pulsed light under measurement.

In the optical waveform measuring device of the present invention, the pulsed light to be measured swept by the light deflecting means is reduced in light intensity outside the sweeping time by the modulation of the light modulating means. As a result, the intensity of the measured pulsed light that enters the photodetector outside the sweep time is reduced. If the intensity of the measured light outside the sweep time is sufficiently reduced, the measured light that passes through the window outside the sweep time becomes almost zero. Therefore, according to the optical waveform measuring apparatus of the present invention, noise generated when the pulsed light under measurement enters the photodetector outside the sweep time is reduced, and sampling measurement with less noise is performed.

When the optical modulator is an electro-optical modulator and the optical deflector is an electro-optical deflector, high-speed intensity modulation and sweeping are performed, and optical waveform measurement is also performed at high speed.

If the first driving electric signal is a signal whose magnitude changes monotonously with the time for rotating the polarization direction of the pulsed light to be measured, the pulsed light to be measured is applied during the application of this driving electric signal. Intensity changes. If the second drive electric signal is a signal whose magnitude monotonously changes in response to the sweep time of the pulse light to be measured, the pulse light to be measured is swept in one direction. If the first and second drive electric signals are properly synchronized, the pulsed light to be measured is modulated so that the light intensity becomes maximum at the timing when the pulsed light to be measured passes through the window of the light shielding means by the sweep. You can As a result, sampling measurement is performed while maintaining the light intensity of the pulse light to be measured sufficiently.

In the optical waveform measuring device of the present invention which is equipped with the spectroscopic means, the spectroscopic means disperses the pulsed light to be measured, so that the optical waveform of the pulsed light to be measured can be measured for each wavelength. Become. The spectroscopic means disperses the pulsed light to be measured on a plane different from the plane on which the pulsed light to be measured is deflected, so that the sweeping does not interfere with the spectroscopy. Therefore, according to this optical waveform measuring apparatus, both the spectroscopic measurement and the optical waveform measurement are suitably performed, and the measurement with a wide range of application becomes possible.

According to the optical waveform measuring device of the present invention in which the light detecting means detects a plurality of pulsed light under measurement, it is possible to simultaneously measure the optical waveforms of a plurality of pulsed light under measurement. This makes it possible to compare optical waveforms,
It enables measurements with a wide range of applications.

[0025]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements will be denoted by the same reference symbols, without redundant description.

Example 1 FIG. 1 is a block diagram of the optical waveform measuring apparatus of this example. This optical waveform measuring apparatus includes an optical system including an electro-optical modulator 140, an electro-optical deflector 104, a Fourier transform lens 105, a slit plate 107 and a photodetector 108, a drive control system including a controller 121 and a high voltage circuit 123,
And amplifier 127, peak hold lock-in amplifier 128, data processor 129 and display 1
An information processing system consisting of 30 is provided.

The electro-optic modulator 140 modulates the intensity of the pulsed light 101 to be measured, and is composed of a polarizer 102, an aperture 103, an optical modulator 110 and an analyzer 111. The polarizer 102 uses the measured pulsed light 10
1 is converted into linearly polarized light in a predetermined direction. Light modulator 110
Rotates the polarization direction of the measured light according to the magnitude of the first drive voltage signal 141 applied from the high voltage circuit 123. The aperture 103 is for narrowing the beam diameter of the linearly polarized light generated by the polarizer 102. The analyzer 111 transmits only linearly polarized light in a predetermined direction. The polarizer 102 and the analyzer 111 are arranged so that the direction of linearly polarized light generated by the polarizer 102 and the direction of linearly polarized light transmitted by the analyzer 111 are orthogonal to each other.

The electro-optical deflector 104 includes a high voltage circuit 123.
The light to be measured is deflected at an angle according to the magnitude of the second drive voltage signal 124 applied from the. The specific configuration will be described later in detail.

The Fourier transform lens 105 collects the light emitted from the electro-optical deflector 104 and forms a Fourier transform image on the slit plate 107.

The slit plate 107 is an opaque plate provided with slits. The width of the slit is about the spot diameter of the pulsed light under measurement which is not deflected.

The photodetector 108 receives the light transmitted through the slit, photoelectrically converts it, and outputs an electric signal 109 having a magnitude corresponding to the light intensity.

The controller 121 controls the measured pulsed light 1
In response to the input of the trigger signal 120 synchronized with 01, the sweep pulse signal 122 is output to the high voltage circuit 123 while giving a predetermined delay time. In addition, the controller 121
The information signal 126 of this delay time is sent to the data processing device 1
Output to 29.

The high voltage circuit 123 has a sweep pulse signal 122.
According to the second drive voltage signal 12 to the electro-optical deflector 104.
4 is applied to the electro-optical modulator 140, and the first drive voltage signal 141 synchronized with the second drive voltage signal 124 is applied.
Is applied.

The data processing device 129 includes a photodetector 108.
The output signal 109 is processed, the measured optical waveform is reproduced based on the delay information signal 126 from the controller 121, and the measured optical waveform is displayed on the display 130.

The operation of the optical waveform measuring apparatus of this embodiment will be described below. FIG. 2 is a waveform diagram for explaining the operation. Measured pulsed light 101 repeatedly incident on the apparatus
FIG. 2A shows an aperture 103 after being converted into linearly polarized light having an electric field vector in the horizontal direction by the polarizer 102.
Is converged by and becomes a beam having an appropriate diameter.

On the other hand, the trigger signal 120 synchronized with the pulsed light 101 to be measured is input to the controller 121, and the controller 121 outputs the sweep pulse signal 122 with an appropriate delay time. In order to perform sampling measurement of the optical waveform, the sweep pulse signal 122 is output with a delay time shifted for each pulse of the measured light.

The high voltage circuit 123 receives the sweep pulse signal 122, applies the second drive voltage signal 124 to the electro-optical deflector 104, and optically modulates the first drive voltage signal 141 synchronized with the second drive voltage signal 124. It is applied to the element 110. As shown in FIG. 2B, the first drive voltage signal 14
The first and second drive voltage signals 124 are repetitive signals of a ramp waveform in which the voltage value linearly changes from 0 to V _H (high level voltage value) over a fixed time. In addition, V
The value of _H is determined by the electro-optical modulator 140 and the electro-optical deflector 10.
The first drive voltage signal 141 and the second drive voltage signal 124 are not necessarily equal to each other, because they are set appropriately in relation to the operation characteristic of No. 4.

The light modulation element 110 has a first drive voltage signal 1
The polarization direction of the measured light is rotated according to the size of 41. The time during which the voltage value of the first drive voltage signal 141 changes linearly corresponds to the time during which the polarization direction of the measured light is rotated.

Specifically, the first drive voltage signal 1
During the time period when the voltage value of 41 is 0, the polarization direction is not rotated, and the polarization direction of the measured light remains orthogonal to the polarization direction of the light transmitted by the analyzer 111. After that, the polarization direction rotates in one direction according to the linear change of the voltage value, and rotates by 180 ° when the voltage value V _H is applied. Analyzer 11
1 transmits the light whose polarization direction is rotated by 90 ° by the light modulation element 110, the pulse light to be measured transmitted through the analyzer 111 corresponds to the applied voltage waveform of FIG. It is modulated into the time waveform of c). The intensity of the modulated pulsed light to be measured has a maximum in the middle of the time period when the applied voltage value changes linearly.

On the other hand, the electro-optical deflector 104 deflects the pulse light to be measured at an angle according to the magnitude of the second drive voltage signal 124. The second drive voltage signal 124 and the first drive voltage signal 141 are applied to the electro-optical deflector 1 at the time when the intensity of the pulse light to be measured modulated by the electro-optical modulator 140 becomes maximum.
The pulsed light under measurement swept by 04 is synchronized so as to directly pass through the slit.

During the time period when the voltage value of the second drive voltage signal 124 is 0, the pulsed light to be measured emitted from the electro-optic modulator 140 is radiated to the side of the slit in the slit plate 107 and directly transmitted through the slit. It is supposed not to. After that, the pulsed light to be measured is swept in one direction according to the linear change of the voltage value. When the voltage value V _H is applied, the pulsed light to be measured is applied to the side of the slit so as not to directly pass through the slit.

The pulse light to be measured emitted from the electro-optical deflector 104 is imaged on the slit plate 107 via the Fourier transform lens 105. On the slit plate 107, the temporal intensity change (temporal waveform) of the pulse light to be measured becomes a spatial intensity change (spatial waveform) (FIG. 2D).

Only the pulse light to be measured that has passed through the slit is detected by the photodetector 108. FIG. 2E shows a spatial waveform of the pulsed light under measurement on the light receiving surface of the photodetector 108. The spatial intensity change of the measured light is cut out by a slit. The cut out light is photoelectrically converted by the photodetector 108, and an electric signal 109 having a level corresponding to the light intensity is output from the photodetector 108.

The output signal 109 is amplified and peak-held by the amplifier 127 and the peak hold / lock-in amplifier 128, and then the data processing device 129.
Is input to The lock-in measurement by the peak hold lock-in amplifier 128 reduces noise and improves the sensitivity of the device.

The data processing device 129 includes a photodetector 10
The output signal 109 of 8 and the delay information signal 126 of the sweep pulse signal 122 are input, and the measured light intensity corresponding to each delay time is obtained. Based on this, the time waveform of the measured light is reproduced. The data processing device 129 is
If necessary, processing such as averaging and deconvolution can be added to the measured optical signal.

The pulsed light to be measured may be introduced into the apparatus using an optical fiber. In this case, the light to be measured emitted from the optical fiber needs to be collimated by a collimator lens. Further, by making the application of the second drive voltage signal a traveling wave type, it is possible to increase the speed and efficiency of the optical waveform measurement.

Next, FIGS. 3 and 4 show the electro-optical deflector 10.
It is a figure which shows an example of No. 4. FIG. 3A shows a quadrupole electrode type electro-optical deflector and FIG. 4 shows a double prism type electro-optical deflector, each of which is composed of one or more electro-optical crystals.

For example, when a voltage is applied to the electro-optical deflector of FIG. 3A as shown in the figure, the electric field in the crystal is changed to z of the crystal.
A strength distribution as shown in FIG. 3B is shown in the axial direction (c-axis direction). Due to the electro-optic effect of the crystal, the refractive index of the electro-optic deflector changes in proportion to the strength of the electric field, and the light incident from the y-axis direction is deflected in the x-direction.

When a lithium niobate crystal is used as this electro-optical deflector, the deflection angle θ _d is expressed by the following equation (1).

[0050]

[Equation 1]

The electro-optical constant r _ij represents the amount of change in the refractive index of light having an electric vector in the i-axis direction when a voltage in the j-axis direction is applied. i and j customarily represent x, y, and z by 1, 2, and 3, respectively. In the case of formula (1), the electric field E
_{Since Z} is in the z-axis direction, j = 3.

Substituting the actual numerical value into the equation (1). z
When linearly polarized light whose electric field vector oscillates in the axial direction is incident, this light is deflected based on the electro-optic constant r ₃₃ .

[0053]

[Equation 2]

The double prism type electro-optical deflector shown in FIG. 4 is formed by laminating two prism-shaped electro-optical crystals with their optical axes reversed. This electro-optical deflector also applies a voltage as shown in the figure to deflect incident light at an angle proportional to the voltage.

An electro-optic crystal can also be used for the light modulation element 110. FIG. 5 is a perspective view showing an optical modulator made of lithium niobate crystal. A crystal axis is set as shown in FIG. 5A, and a voltage is applied in the x-axis direction. Figure 5
As shown in (b), the intrinsic polarization direction becomes the x ', y'axis directions rotated by 45 ° with respect to the x, y axes by applying a voltage. The phase change Δφ of the light incident on the crystal is Δφ = (2π / λ) · n ³ · r ₂₂ · E · L (2) λ: wavelength n: refractive index r ₂₂ : electro-optic constant E: in crystal The electric field L is expressed as L: crystal length.

Λ where the electric field vector oscillates in the x-axis direction
When linearly polarized light of 633 nm is incident,
= 2.2, r ₂₂ = 6.7 × 10 ^-12 m / V, E = 4 kV
Substituting / cm and L = 10 mm, Δφ = π,
The light transmitted through the crystal becomes linearly polarized light in the y-axis direction. Therefore, as in this embodiment, if an analyzer that transmits light polarized in the y-axis direction is arranged after the crystal, the light intensity can be modulated according to the magnitude of the voltage applied to the light modulation element. You can

The electro-optical polarizer 1 as in this embodiment
When applying the voltage of the same waveform to 04 and the light modulation element 110, it is necessary to adjust the length of the electro-optic crystal so that Δφ = π.

In addition to the lithium niobate (LiNbO ₃ ) crystal, another crystal having an electro-optical effect is used as the light modulation element 1.
10 and the electro-optical deflector 104 can be used. Specifically, LiTaO ₃ showing almost the same characteristics as LiNbO ₃ , GaAs and CdTe useful for polarization and modulation of infrared light, CuCL usable for both visible light and infrared light
Etc. can be used. Besides this, NH ₄ H ₂ PO
₄ (ADP), KH ₂ PO ₄ (KDP), KD ₂ PO ₄
It is possible to use an electro-optic crystal such as (KD ^* P) or KTa _X Nb _1-X O ₃ (KTN).

Embodiment 2 FIG. 6 is a configuration diagram of an optical waveform measuring apparatus of Embodiment 2. The optical waveform measuring apparatus of this embodiment includes a diffraction grating 112 arranged on the optical path between the electro-optical deflector 104 and the Fourier transform lens 105, and a pinhole plate 113 is arranged instead of the slit plate 107. This is different from the first embodiment. In the drawings, the drive control system and the information processing system are omitted (this is the same in the following embodiments). The optical waveform measuring device of this embodiment performs spectroscopic measurement together with sampling measurement.

The pulsed light to be measured emitted from the electro-optical deflector 104 and incident on the diffraction grating 112 is emitted at different angles for each wavelength. This spectroscopy is performed on a plane orthogonal to the plane on which the pulse light to be measured is deflected. Only the light that enters the pinhole of the pinhole plate 113 out of the measured pulsed light that has been dispersed is detected by the photodetector 108, and the optical waveform thereof is sampled and measured. The wavelength of the light to be measured can be selected by moving the pinhole plate 113. Note that another spectroscope (prism or the like) can be used instead of the diffraction grating 112.

Example 3 FIG. 7 is a block diagram of an optical waveform measuring apparatus of Example 3. The optical waveform measuring apparatus according to the present embodiment is similar to the optical waveform measuring apparatus according to the second embodiment except that the slit plate 10 is used instead of the pinhole plate 113.
7 are arranged. A one-dimensional image sensor 106 is used as the photodetector 108.

All the measured pulsed light that has been dispersed by the diffraction grating 112 passes through the slits of the slit plate 107,
In the image sensor 106, the light enters different pixels for each wavelength. It is possible to perform sampling measurement for each wavelength by performing gate control on the output of the image sensor 106 and extracting the signal of one pixel.

Embodiment 4 FIG. 8 is a block diagram of an optical waveform measuring apparatus of Embodiment 4. The optical waveform measuring apparatus according to the present embodiment includes a plurality of photodetectors 108 so as to simultaneously measure a plurality of pulsed lights under measurement.
The plurality of light under measurement enter different photodetectors 108 by changing the incident angle on the electro-optical deflector 104. By processing the output of each photodetector 108, it is possible to measure the optical waveforms of a plurality of pulsed lights to be measured. If an information processing system is prepared for each photodetector, it is possible to simultaneously measure optical waveforms of a plurality of light under measurement. Note that one image sensor may be used instead of using the plurality of photodetectors 108.

Fifth Embodiment FIG. 9 is a block diagram of the optical waveform measuring apparatus of the fifth embodiment. The optical waveform measuring apparatus according to the present embodiment includes a half mirror 114 arranged on the optical path between the optical modulator 140 and the electro-optical deflector 104, and a total reflection mirror that reflects the light emitted from the electro-optical deflector 104. 115 are provided. The optical waveform measuring apparatus according to the present embodiment increases the deflection angle of the electro-optical deflector 104.

Of the pulsed light under measurement whose intensity has been modulated by the optical modulator 140, one that has passed through the half mirror 114 is deflected by the electro-optical deflector 104. The deflected light to be measured is reflected by the total reflection mirror 115, enters the electro-optical deflector 104 again, and is deflected. After that, the measured light emitted from the electro-optical deflector 104 is reflected by the half mirror 1.
The light is reflected at 14, detected by the photodetector 108, and sampled and measured. The measured light is the electro-optical deflector 104.
Is transmitted twice, the deflection angle is doubled, and the time resolution of the optical waveform measuring device is also doubled.

[0066]

As described in detail above, according to the optical waveform measuring apparatus of the present invention, the light intensity outside the sweep time is reduced by the modulation of the light modulating means. The noise caused by is reduced, and sampling measurement with less noise can be performed.

In the optical waveform measuring device of the present invention, the optical modulation means is an electro-optical modulator and the optical deflection means is an electro-optical deflector, which enables high-speed intensity waveform modulation and high-speed optical waveform measurement. It can be carried out. Further, according to the one in which the drive control means applies the first and second drive electric signals whose magnitudes monotonously change in response to the predetermined time to the light modulation means and the light deflection means, the first and second By appropriately synchronizing the drive electric signal of, the pulsed light to be measured is modulated so that the light intensity becomes maximum at the timing when the pulsed light to be measured passes through the window of the light shielding means by the sweep.
It is possible to easily perform sampling measurement while sufficiently maintaining the light intensity of the measured pulsed light.

In the optical waveform measuring apparatus of the present invention which is provided with the spectroscopic means, the optical waveform is measured together with the spectral measurement of the pulsed light to be measured, and the spectrum is not disturbed by the sweep. Both can be suitably performed. This enables measurement with a wide range of applications.

According to the optical waveform measuring device of the present invention in which the light detecting means detects a plurality of pulsed light under measurement, it is possible to simultaneously measure the optical waveforms of a plurality of pulsed light under measurement. This enables measurement with a wide range of applications, such as comparing optical waveforms.

[0070]

[Brief description of drawings]

FIG. 1 is a configuration diagram of an optical waveform measuring device according to a first embodiment.

FIG. 2 is a waveform diagram for explaining the operation of the optical waveform measuring device according to the first embodiment.

FIG. 3 is a diagram showing a quadruple electrode type electro-optical deflector.

FIG. 4 is a diagram showing a double prism type electro-optical deflector.

FIG. 5 is a diagram showing an optical modulator made of a lithium niobate crystal.

FIG. 6 is a configuration diagram of an optical waveform measuring device according to a second embodiment.

FIG. 7 is a configuration diagram of an optical waveform measuring device according to a third embodiment.

FIG. 8 is a configuration diagram of an optical waveform measuring device according to a fourth embodiment.

FIG. 9 is a configuration diagram of an optical waveform measuring device according to a fifth embodiment.

FIG. 10 is an overall configuration diagram of a conventional solid streak tube.

11A is a waveform diagram of a sweep voltage, FIG. 11B is a waveform diagram showing a temporal intensity change of the pulsed light to be measured, and FIG. 11C is a waveform diagram showing a spatial intensity change of the pulsed light to be measured. is there.

FIG. 12 is an overall configuration diagram of a conventional optical waveform measuring device.

FIG. 13 is a diagram for explaining a sampling method of a conventional optical waveform measuring device.

FIG. 14 is a waveform diagram for explaining the operation of the conventional optical waveform measuring device.

[Explanation of symbols]

101 ... Pulse light to be measured, 102 ... Polarizer, 103 ... Aperture, 104 ... Electro-optical deflector, 105 ... Fourier transform lens, 107 ... Slit plate, 108 ... Photodetector,
109 ... Output signal, 110 ... Optical modulator, 111 ... Analyzer, 120 ... Trigger signal, 121 ... Controller, 12
2 ... Sweep pulse signal, 123 ... High voltage circuit, 124 ... Sweep voltage, 126 ... Delay information signal, 127 ... Amplifier, 1
28 ... Peak hold lock-in amplifier, 129 ... Data processing device, 130 ... Display, 140 ... Electro-optical polarizer, 141 ... Driving voltage.

Claims (7)

[Claims] 1. A light modulating means for modulating the intensity of repetitively incident measured pulsed light according to the magnitude of an applied first drive electric signal, and the measured pulsed light emitted from the optical modulating means. Is deflected at an angle according to the magnitude of the applied second drive electric signal to sweep the pulsed light to be measured, and an opaque light in which a transparent window is formed. Has an entrance surface,
Light shielding means for transmitting the pulsed light to be measured deflected at a predetermined angle by the light deflecting means from the window portion, and receiving the pulsed light to be measured transmitted through the light shielding means,
Light detection means for outputting an electric signal of a level according to the light intensity, and the first drive electric signal is applied to the light modulation means at different timings for each pulse of the light to be measured, and the light deflection is applied. Drive control means for applying the second drive electric signal to the means at different timings for each pulse of the light to be measured, and outputting information on the application timing deviation of the second drive electric signal; Information processing means for obtaining the waveform of the pulse light to be measured based on the information on the timing deviation and the output signal of the light detecting means, wherein the light modulating means outputs the pulse to be measured emitted from the light modulating means. An optical waveform measuring device, characterized in that the intensity of the light outside the sweep time is reduced as compared with that before the light enters the light modulating means. 2. The light modulating means is applied with a polarizer for converting the pulsed light to be measured into linearly polarized light in a predetermined direction and the first drive electric signal, and the polarized light is generated in accordance with the magnitude of the signal. Electro-optical modulator including an electro-optical crystal that rotates the polarization direction of the pulsed light to be measured emitted from a child, and an analyzer that receives the emitted light from the electro-optical crystal and transmits linearly polarized light in a predetermined direction. 2. The optical waveform measuring device according to claim 1, wherein the light deflecting means is an electro-optical deflector including one or more electro-optical crystals to which the second drive electric signal is applied. 3. The drive control means sends to the light modulation means a signal whose magnitude monotonously changes according to the time for rotating the polarization direction of the pulse light to be measured, as the first drive electrical signal. 3. A signal which is applied and whose magnitude is monotonically changed corresponding to the sweep time of the pulse light to be measured is applied to the light deflection means as the second drive electric signal. Optical waveform measuring device. 4. The spectroscopic means for emitting the pulsed light to be measured emitted from the light deflecting means in different directions for each wavelength on a plane different from the plane on which the pulsed light to be measured is deflected, further comprising: The optical waveform measuring device according to claim 1, wherein the optical waveform of the measurement pulsed light is measured for each wavelength. 5. The light shielding means is a pinhole plate having a pinhole as the window portion, and movement of the pinhole plate causes light of a desired wavelength out of the measured pulsed light emitted from the spectroscopic means. The optical waveform measuring device according to claim 4, wherein 6. The light shielding means is a slit plate having a slit as the window portion for transmitting all the measured pulsed light emitted in different directions for each wavelength from the spectroscopic means, and the light detecting means is 5. An image sensor for receiving the pulsed light to be measured that has passed through a slit plate, wherein the optical waveform of the pulsed light to be measured is measured for each wavelength based on the light receiving position on the image sensor. The optical waveform measuring device described. 7. The light detecting means receives a plurality of measured pulse lights emitted from the light shielding means in different directions according to the traveling directions of the plurality of measured pulse lights, and detects each measured pulse light. The optical waveform measuring device according to claim 1, wherein the optical waveform measuring device comprises: