JP3084685B2 - Optical sampling optical waveform measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is used for measuring the waveform of an optical signal. In particular, the present invention relates to an extremely high-speed optical signal waveform measurement technique.

The present invention relates to an application technique of a new short-pulse white light source described in the specification and drawings of a patent application (Japanese Patent Application No. 5-78095, not published at the time of filing of the present application) filed by the applicant of the present invention. .

[0003]

2. Description of the Related Art An optical sampling optical waveform measurement is a method in which an optical pulse to be observed and a sampling optical pulse having a sufficiently narrower pulse width are guided to a nonlinear optical material, and a cross-correlation signal between the two is taken out using a nonlinear optical effect. Since the measured light can be sampled in the optical region, it is expected that the waveform of an ultra-high-speed optical signal can be observed with high time resolution.

[0004] Sum frequency light generation (SFG: Sum Freqen) which is one of the second-order nonlinear optical effects is one of the nonlinear optical effects.
cy Generation) (References Takara et al .: "Ultrafast Optical Waveform Measurement Method by Optical Sampling Using Sum Frequency Light Generation",
IEICE Transactions, BI, vol.J75-BI, No.5, pp.3
72-380, 1992) and Four-Wave Mixing (FWM), which is a third-order nonlinear optical effect (reference PAAnd)
rekson, Electron. Lett. 27, 1440 (1991)).

FIG. 8 is a diagram showing the relationship between the optical frequency and the optical intensity in the case of SFG and FWM. The horizontal axis represents the light frequency, and the vertical axis represents the light intensity. In the figure, f _sam , f _sig and f
_sfg and f _fwm are the sampling light frequency, the measured light frequency, the sum frequency light frequency, and the FWM light frequency, respectively. P
_sam , P _sig , P _sfg , and P _fwm are the sampling light intensity, the measured light intensity, the sum frequency light intensity, and the FWM light intensity, respectively.

[0006] As shown in FIG. 8 (a), the SFG is the sum of the optical frequencies f _{sig when} the two light waves of the measured light having the optical frequency f _sig and the sampling light having the optical frequency f _sam are incident on the second-order nonlinear optical material. _sfg = is a phenomenon in which light is generated by the f _sig + f _sam. FWM generally means that new light (optical frequency f ₄ = f ₁ + f ₂ −f ₃ ) is generated by _three incident lights (optical frequencies f ₁ , f ₂ , f ₃ ) as shown in FIG. 8B. In the case of application to optical sampling, the use of three types of light complicates the configuration. Therefore, usually, an FWM in which _two light waves are degenerated (f ₁ = f ₂ ) is used. That is, f ₁ ,
A sampling light frequency f _sam is incident as f ₂ , and f ₃
As by launching the light under measurement frequency f _sig, optical frequency as shown in FIG. _{8 (b) f fwm = 2f} sam -f
_{The sig} FWM light is generated. As this first nonlinear optical material, KTP or another ferroelectric crystal is mainly used for SFG, and an optical fiber or other quartz optical waveguide is used for FWM.

[0007]

However, in practice, the time resolution of the optical sampling optical waveform measurement method is mainly determined by the pulse width of the sampling optical pulse. Conventionally, a pulsed light source shown in FIG. 9 has been mainly used as a sampling light source. FIG. 9 is a diagram showing a conventional pulse light source. FIG.
(A), (b), and (c) are configuration diagrams of a ring resonator mode-locked laser, a Fabry-Perot resonator mode-locked laser, and a gain switching semiconductor laser, respectively. Voltage amplifier 71, DC voltage source 72, optical modulator 73, optical amplifier 7
4. An optical delay unit 75, an optical bandpass filter 76, an optical coupler 77, a mirror 78, a semiconductor laser 79, and a pulse compression dispersion medium 80. These pulse light sources generate an optical pulse train having the sampling frequency f ₀ / n-Δf shown in FIG. 9A using the electric signal in FIG.
However, there is a drawback that the pulse width of these output lights is several ps or more, so that the time resolution is only about several ps.

[0008] The efficiency of the nonlinear optical effect of SFG or FWM depends on the optical frequency of the light to be measured and the sampling light. The intensity of the sum-frequency light generated when the measured light and the sampling light are incident on the second-order nonlinear optical crystal is P _sfg = 8 (μ ₀ / ε ₀ ) ^3/2 · [(π ² c ² d ² L ² ) / (λ ² n ³ )] · [(P _sam P _sig ) / A _eff ] · [(sin ² (ΔkL / 2) / (ΔkL / 2) ² ] (1) Δk = (2π / c) ) · (F _sfg n _sfg -f _sam n _sam -f _sig n _sig ) (2) (Reference A. Yariv, “Basics of Optoelectronics”, 3rd edition, Maruzen Co., Ltd. P2
63). Here, λ is the wavelength, c is the luminous flux, A _eff is the effective area, L is the length, and d is the second-order nonlinear susceptibility. Δk is a parameter indicating a phase mismatch. By appropriately setting the optical frequency f _sam of the sampling light and the optical frequency f _sig of the measured light, Δk = 0, and the sum frequency light intensity P
_sfg becomes the maximum.

However, in the case of the conventional optical sampling, the optical frequency f _sam of the sampling light is fixed, and the optical frequency f _sig of the light to be measured is not specified. FIG. 10 is a diagram illustrating the relationship between the optical frequency to be measured and the cross-correlation signal light intensity. The horizontal axis represents the optical frequency to be measured, and the vertical axis represents the cross-correlation signal light intensity. FIG. 10 shows the relationship between the sum frequency light intensity and the measured light frequency f _sig at this time calculated by the equations (1) and (2). As the optical frequency f _sig of the light to be measured departs from the optimal optical frequency f _{max, the} SFG light intensity decreases. That is, since the sum frequency light intensity as the cross-correlation signal depends on the optical frequency f _sig of the light to be measured, it is difficult to measure the optical waveform in a wide optical frequency band.

In the FWM, the sum frequency light intensity, which is a cross-correlation signal, is equal to the optical frequency f
Depends on _sig . When an optical fiber is used as a nonlinear optical material, the FWM light intensity is

[0011]

(Equation 1) (Ref. Inoue, "Four-Wave mixing in a
n optical fibar in thezero-dispersion wavelength r
egion ", J.of Lightwave Technology, 10, PP.1553-1561 (1
992)). Here, α is a loss coefficient, D is a degeneration coefficient, and X is a third-order nonlinear susceptibility. Δβ is a parameter indicating a phase mismatch. When the two light waves are degenerated as described above, Δβ = − [(λ ⁴ π) / c ² ] [(dD _c ) / (dλ)] 2 (f _sam − f _sig ) ² · (f _sam −f ₀ ) (4) D _c and f ₀ are optical frequencies at which chromatic dispersion and zero dispersion of the nonlinear optical material are obtained, respectively. When the optical frequency f _sig of the light to be measured becomes equal to the optical frequency f _{sam of the} sampling light, Δβ = 0, and the FWM light intensity becomes maximum. However, as the optical frequency f _sig of the light to be measured departs from the optical frequency f _{sam of the} sampling light, the FWM light intensity decreases. Therefore, similarly to the SFG, the sum frequency light intensity, which is the cross-correlation signal, of the FWM depends on the optical frequency f _sig of the light to be measured, so that it is difficult to measure the optical waveform in a wide optical frequency band.

SUMMARY OF THE INVENTION The present invention has been made in view of such a background, and in an optical sampling optical waveform measuring apparatus using a nonlinear optical effect, a supercontinuity having a narrow pulse width and a wide band continuous optical frequency as sampling light is provided. It is an object of the present invention to provide an optical sampling optical waveform measuring device having a higher time resolution and a larger optical frequency variable region by using a new optical pulse. An object of the present invention is to provide an optical sampling optical waveform measurement with little dependence on the optical frequency of the light to be measured.

[0013]

SUMMARY OF THE INVENTION Optical sampling of the present invention
In the optical waveform measuring device, the sampling light generating unit includes a pulse light source that generates a light pulse train and a second light source that converts the light pulse into supercontinuum light having a broadband spectrum.
It is characterized by comprising a non-linear optical material and a wavelength variable optical filter for selecting a sampling light pulse having a desired center wavelength and a desired spectral width from the supercontinuum light.

The first non-linear optical material is an optical signal to be measured.
(Optical frequency f_sig) And sampling light (optical frequency
f_sam) As the cross-correlation signal
Frequency f_sig + F_sam) Or four-wave mixing light (optical frequency
2f_sam−f_sig). Ma
In addition, quartz-based light is used as the first and second nonlinear optical materials.
Waveguide or semiconductor waveguide or ferroelectric versus crystal or strong
Characterized in that a dielectric pair waveguide or an organic waveguide is used.
You.

When the supercontinuum light generated from the first nonlinear optical material has chirping, a pulse compressor having wavelength dispersion for compensating for chirping is provided.

That is, the present invention provides a coupler (7) for coupling the output light of the light source to be measured (2) and the output light of the sampling light source (4), and a photodetector for detecting the output light of the coupler. (10) An optical sampling optical waveform measuring apparatus comprising: a means for displaying an output signal of the photodetector in synchronization with the sampling light source and the light source to be measured.

Here, a feature of the present invention is that the sampling light source (4) includes a pulse light source, a first nonlinear optical material irradiated with output light of the pulse light source,
A wavelength tunable optical filter for selecting a desired wavelength from supercontinuum light radiated from the first nonlinear optical material.

Thus, the optical waveform can be measured over a wide wavelength range using the white ultrashort pulsed light.

A second nonlinear optical material to which the output light of the coupler (7) is irradiated, and an optical filter (9) through which light emitted by the second nonlinear optical material passes; It is desirable that the light transmitted through the optical filter (9) be introduced into the vessel (10).

A polarization controller which is inserted into the output light path of the light source to be measured (2) and the output light path of the sampling light source (4) and applies a polarization so as to be compatible with the second nonlinear optical material. Is desirable.

It is preferable that the sampling light source (4) includes a dispersion compensator (21) for passing the super continuum light and shortening a pulse time width thereof. Thus, an optical pulse having a short pulse time width can be obtained.

It is preferable that the first nonlinear optical material is configured as a material of a waveguide through which the output light of the pulse light source passes.

[0023]

The output light of the light source to be measured (2) and the output light of the sampling light source (4) are combined by a combiner (7). The photodetector (10) detects the output light of the coupler. The output signal of the photodetector is displayed in synchronization with the sampling light source and the light source to be measured.

In the present invention, when the first nonlinear optical material included in the sampling light source (4) is irradiated with the output light from the pulse light source, supercontinuum light is emitted from the first nonlinear optical material. You. A desired wavelength can be selected from the super continuum light using a variable wavelength optical filter. This makes it possible to perform optical waveform measurement over a wide wavelength range using white ultrashort pulsed light.

An optical filter (9) is provided at a position where the output light of the coupler (7) is irradiated with the second nonlinear optical material, and the light emitted by the second nonlinear optical material passes therethrough. The light transmitted through the optical filter (9) is preferably introduced into the photodetector (10). A low-speed cross-correlation signal with a repetition frequency Δf is obtained from the second nonlinear optical material, and only this can be extracted by an optical filter and used as a trigger for display timing.

A polarization controller may be inserted into the output light path of the light source under measurement (2) and the output light path of the sampling light source (4), respectively, and may provide polarization so as to be compatible with the second nonlinear optical material. .

It is preferable to provide a dispersion compensator in the sampling light source (4) so as to pass super continuum light and shorten the pulse time width. .

The first nonlinear optical material is preferably formed as a material of a waveguide through which the output light of the pulse light source passes.

That is, an optical pulse train generated from an optical pulse light source is converted into supercontinuum light having a broadband spectrum by a nonlinear optical material. A sampling light pulse having a desired center wavelength and a desired spectral bandwidth is selected from the super continuum light by the wavelength tunable optical filter.

The optical pulse train obtained as described above can be used as a sampling optical pulse by cutting an arbitrary band from a continuous wide band as required, so that an optical waveform can be easily measured.

A pulse compressor as a dispersion compensator;
Super continuum light chirping can be compensated.

As the nonlinear optical material, a quartz-based optical waveguide, a semiconductor waveguide, an organic crystal, or an organic waveguide is preferably used.

As the pulse compressor, a quartz optical waveguide, a semiconductor waveguide, a diffraction grating pair, a prism pair, or a Gires-Tournois interferometer is preferably used.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a configuration diagram of the first embodiment of the present invention. FIG. 2 is a block diagram of the optical pulse source.

According to the present invention, a coupler 7 for coupling the output light of the light source 2 to be measured and the output light of the sampling light source 4, a photodetector 10 for detecting the output light of the coupler 7, and a photodetector 10 This is an optical sampling optical waveform measuring apparatus including a display section 14 as a means for displaying the output signal of the sample 10 in synchronization with the sampling light source 4 and the light source 2 to be measured.

Here, a feature of the present invention is that, as shown in FIG.
8, a non-linear optical material 20 for generating SC (super continuum) as a first non-linear optical material irradiated with the output light of the pulse light source 18, and a non-linear optical material 20 radiated from the non-linear optical material 20 for generating SC And a tunable bandpass filter 22 as a tunable optical filter for selecting a desired wavelength from the continuum light.

A second nonlinear optical material 8 to which the output light of the coupler 7 is irradiated, and an optical filter 9 through which light emitted by the nonlinear optical material 8 passes. Nine transmitted lights are introduced.

A polarization controller 5 which is inserted into the output light path of the light source 2 to be measured and the output light path of the sampling light source 4 and gives polarization so as to be compatible with the nonlinear optical material 8;
6 is provided.

As shown in FIG. 2, the sampling light source 4 is provided with a dispersion compensator 21 for transmitting super continuum light and shortening the pulse time width.

The SC-generating nonlinear optical material 20 is formed as a material of a waveguide through which the output light of the pulse light source 18 passes.

In the drawing, a thick solid line indicates the flow of an optical signal, and a thin solid line indicates the flow of an electric signal. The measured light source clock oscillator 1 and the measured light source 2 are each provided as an external device. On the other hand, the sampling frequency f ₀ / n
A sampling frequency oscillator 3 that oscillates -Δf (n: natural number) and a sampling light source 4 are provided. The oscillation output from the sampling frequency oscillator 3 is guided to the mixer 12, where the electric pulse of f ₀ / n obtained by dividing the frequency f ₀ from the clock oscillator 1 for the light source to be measured by the frequency dividing circuit 15 is used as the above-mentioned oscillation output. Mix. The mixed output is supplied to the electric low-pass filter 13 to extract a component of the frequency Δf to be a trigger signal, and the trigger signal is displayed on the display unit 14.
To supply.

In general, the exchange efficiency of the nonlinear optical effect of SFG or FWM depends on the polarization state of incident light. Therefore, the light to be measured having the frequency f ₀ from the light source 2 to be measured and the sampling light having the frequency f ₀ / n−Δf from the sampling light source 4 are guided to the polarization controllers 5 and 6, respectively, where the polarization of the light pulse is obtained. The state is adjusted to the optimum state for the nonlinear optical material 8. The measured light and the sampling light whose polarization states have been adjusted are guided to the nonlinear optical material 8 via the coupler 7, and a low-speed cross-correlation signal having a repetition frequency Δf is obtained. After extracting only the cross-correlation signal by the optical filter 9, the light is received by the photodetector 10 and converted into an electric signal. Thereafter, the signal is supplied to the signal processing unit 11, subjected to appropriate signal processing, and then supplied to the display unit 14. Display 14
Then, the output from the signal processing unit 11 is displayed at the timing of the trigger signal Δf.

That is, in this optical sampling light waveform measuring method, another sampling light pulse having a pulse width narrower than that of the light pulse to be measured is superimposed on the light to be measured, made incident on the nonlinear optical material 8, and furthermore, When the pulse delay is swept, a waveform drawn by the cross-correlation signal light power generated in proportion to the overlapping portion of both light pulses is displayed on the display unit 1.
By displaying on the display 4, the measured light waveform is measured.

A second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a block diagram of the second embodiment of the present invention. In the first embodiment of the present invention, an oscillator having a sampling frequency f ₀ / n-Δf is used as a means for sweeping the delay of the sampling light with respect to the measured light. In the second embodiment of the present invention, as shown in FIG. There is also a method of generating a sampling frequency f ₀ / n−Δf using a sweep signal oscillator 17 having a frequency Δf and a frequency shifter 16.

FIG. 4 shows the change in the temporal relative position between the optical pulse to be measured and the sampling optical pulse in the optical sampling optical waveform measuring method using the SFG or FWM, and the low-speed cross-correlation signal optical waveform obtained thereby. Show. FIG.
FIG. 3 is a diagram illustrating a relationship among a measured light, a sampling light, and a cross-correlation signal light. The repetition frequency of the sampling light pulse shown in FIG. 4B is made lower (or higher) by Δf (Hz) than the repetition frequency f ₀ [Hz] of the measured light pulse shown in FIG. 4A. A cross-correlation signal light of Δf (Hz) as shown in FIG. In the example of FIG. 4, the case where the frequency of the optical pulse to be measured is substantially equal to the frequency of the sampling optical pulse has been described. However, the sampling frequency itself may be near an integral number (f ₀ / n (Hz)).

Therefore, this optical sampling optical waveform measuring method uses the nonlinear optical effect having a very fast response speed of about f _sec to sample the optical waveform to be measured and expand the time axis of the optical waveform to be measured. Since the measurement can be performed, it is possible to detect a high-speed optical pulse waveform with extremely high time resolution.

As the SC generating nonlinear optical material 20, a quartz optical waveguide was used as an optical fiber. In addition, a semiconductor waveguide, a ferroelectric crystal, a ferroelectric paired waveguide, an organic crystal, or an organic waveguide can be used.

As the nonlinear optical material 8, a quartz optical waveguide was used. In addition, a semiconductor waveguide, an organic crystal, or an organic waveguide can be used.

For the dispersion compensator 21, a quartz optical waveguide was used as an optical fiber. Alternatively, a semiconductor waveguide or a diffraction grating pair or a prism pair or a Gires-Tou
An rnois interferometer can be used.

The present invention is characterized in that, in the optical sampling optical waveform measuring device, an ultrashort pulse light source having a variable wavelength is used as a sampling light source. As shown in FIG. 2, a pulse light source 18 for excitation, optical amplifiers 19 and 23, S
It comprises a nonlinear optical material 20 for C generation, a dispersion compensator 21 (pulse compressor), and a wavelength-variable optical bandpass filter 22. As the excitation pulse light source 18, a mode-locked laser, a gain switching semiconductor laser, and the like described in the related art can be used. As the optical amplifiers 19 and 23, a rare-earth-doped fiber such as Er, a waveguide, a semiconductor laser amplifier or the like can be used.

Next, the operation of the first and second embodiments of the present invention will be described with reference to FIG. FIG. 5 shows an excitation pulse train. The excitation light pulse train (FIG. 5A) generated from the excitation pulse light source 18 is amplified by the first optical amplifier 19 and then enters the SC generating nonlinear optical material 20. At this time, by setting the wavelength λ _{pump of the} pumping light and the zero dispersion wavelength of the SC generating nonlinear optical material 20 to be close to each other, and amplifying the peak power of the pumping light to be sufficiently high (1 W or more), the SC generating The conversion from the excitation light pulse train to the SC light occurs in the nonlinear optical material 20 (reference T. Morioka et al.
al., "Nearly penetly-free, 4ps supercontinuum WDM p
ulse generation for Tbit / s TDM-WDM network, OFC94,
PD21, 1994). This SC light is an optical pulse train having a spectral width in a wide wavelength range of 200 nm or more as shown in FIG. At this time, if the SC light has chirping due to the dispersion characteristic of the SC generating nonlinear optical material 20 (the optical frequency differs in time within the light pulse), the chirping is performed using the dispersion compensator 21. This is controlled to generate an optical pulse train without chirping (FIG. 5C). SC
S immediately after generation nonlinear optical material 20 without chirping
When C light is obtained, the dispersion compensator 21 is unnecessary. Then, the SC light having the desired wavelength λ _sam (optical frequency f _sam ) is cut out using the wavelength variable band-pass filter 22 (FIG. 5D), and amplified by the second optical amplifier to obtain a sampling light pulse train. At this time, if the output light of the wavelength tunable bandpass filter 22 has a peak power sufficient for generating the cross-correlation signal at the subsequent stage, the second optical amplifier is unnecessary.

The spectral bandwidth of the obtained sampling light pulse is determined by the bandwidth of the tunable bandpass filter 22. Assuming that this bandwidth is Δf and the light pulse width is Δt, their product (time bandwidth product)
Is Δf · Δt ≧ A (5), which is equal to or greater than the Fourier transform limit value. Here, A is a value determined by the shape of the light pulse. For example, A = 0.44 for the Gaussian type and A = 0.3 for the sech2 type.
It becomes 1. In particular, a light pulse in the case where the equality holds in the equation (5) is called a Fourier transform limit pulse. If there is no chirping for the SC light, a Fourier transform limit pulse is obtained. Accordingly, the pulse width Δt of the SC light is as follows: Δt = A / Δf (6) It can be seen that an optical pulse with a narrow pulse width can be obtained by increasing the bandwidth Δf. For example, Δf = 6
Set to 50 GHz (wavelength: about 5 nm) and set the light pulse wavelength to Ga
Assuming the usian type, an ultrashort light pulse (Δt = 0.5 ps) having a pulse width of about 1/10 as compared with the output light pulse of the conventional sampling light source can be obtained. Therefore, according to the present invention, a sampling light pulse having a narrower pulse width than that of the related art can be obtained, so that the optical sampling light wavelength measurement with high time resolution can be performed.

Further, since the SC light has a very wide optical frequency band, a sampling light having an arbitrary center optical frequency within this band can be obtained by the wavelength variable bandpass filter. FIG. 6 is a diagram illustrating changes in the measured light and the sampling light in the case of SFG. The horizontal axis represents the light frequency, and the vertical axis represents the light intensity. Thus, for a SFG, by adjusting also vary the optical frequency of the measured light, as shown in FIG. 6 and f _sig2 from f _sig1 to follow it to the optical frequency of the sampling light from the f _sam1 and f _sam2, The value of Δk in equation (2) described in the prior art can always be set to a constant value. FIG. 7 is a diagram illustrating the relationship between the optical frequency to be measured and the intensity of the cross-correlation signal light. The horizontal axis indicates the frequency of the light to be measured, and the vertical axis indicates the cross-correlation signal light intensity.
As a result, as shown in FIG. 7, it is possible to perform optical sampling optical waveform measurement in which the intensity of the cross-correlation signal light hardly depends on the optical frequency of the measured light. That is, according to the present invention, it is possible to measure an optical waveform in a wide band of an optical frequency of 20 THz (wavelength 200 nm) or more.

On the other hand, in the case of FWM, Δβ is the difference between the optical frequency of the sampling light and the optical frequency of the measured light (f _sam −f
_sig ), it depends on the difference (f _sam −f ₀ ) between the optical frequency of the sampling light and the zero-dispersion optical frequency of the nonlinear optical material. Even if the optical frequency is adjusted, Δβ cannot be set to a constant value. However, since (f _sam −f _sig ), which is proportional to Δβ squared, can always be a constant value, it is possible to measure the optical sampling optical waveform with less dependence on the optical frequency of the measured optical light than before.

[0055]

As described above, according to the present invention,
By using supercontinuum light as the sampling light, the time resolution can be significantly improved. Further, it is possible to realize optical sampling optical waveform measurement with little dependence on the optical frequency of the measured light.

[Brief description of the drawings]

FIG. 1 is a block diagram of a device according to a first embodiment of the present invention.

FIG. 2 is a block diagram of an optical pulse source.

FIG. 3 is a block diagram of a device according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a relationship among a measured light, a sampling light, and a cross-correlation signal light.

FIG. 5 is a diagram showing an excitation pulse train.

FIG. 6 is a diagram showing changes in measured light and sampling light in the case of SFG.

FIG. 7 is a diagram showing a relationship between a measured light optical frequency and a cross-correlation signal light intensity.

FIG. 8 is a diagram showing a relationship between an optical frequency and an optical intensity in the case of SFG and FWM.

FIG. 9 is a view showing a conventional pulse light source.

FIG. 10 is a diagram showing a relationship between a measured light optical frequency and a cross-correlation signal light intensity.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Clock source for light source to be measured 2 Light source to be measured 3 Sampling frequency oscillator 4 Sampling light source 5, 6 Polarization controller 7 Coupler 8 Nonlinear optical material 9 Optical filter 10 Photodetector 11 Signal processing unit 12 Mixer 13 LPF 14 Display unit 15 Frequency dividing circuit 16 Frequency shifter 17 Sweep signal oscillator 18 Pulse light source 19, 23 Optical amplifier 20 Non-linear optical material for SC generation 21 Dispersion compensator 22 Wavelength variable band pass filter 71 Voltage amplifier 72 DC voltage source 73 Optical modulator 74 Optical amplifier 75 Optical delay unit 76 Optical bandpass filter 77 Optical coupler 78 Mirror 79 Semiconductor laser 80 Dispersion medium for pulse compression

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masatoshi Saruwatari 1-6-1 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Kunihiko Mori 1-16-1 Uchisaiwaicho, Chiyoda-ku, Tokyo Japan (56) References JP-A-2-12227 (JP, A) Electronics Letters, Vol. 30, No. 14, pp. 1152-1153 (issued on July 7, 1994) H. Takara et al. (58) Fields investigated (Int. Cl. ⁷ , DB name) G01J 1/00-1/60 G01J 11/00 G02F 1/35-1/39 JICST file (JOIS) WPI (DIALOG)

Claims (5)

(57) [Claims] (1)Outputs the measured optical signalLight source to be measured
(2)When, Outputs sampling light including the first nonlinear optical material
 Sampling light source (4)When, The measured optical signal and the sampling light Join
The combiner (7) and the output light of this combinerIs input and the output light of the light source to be measured is
And a nonlinear optical effect on the output light of the sampling light source.
Providing a second nonlinear optical material (8); The output of this second nonlinear optical material Detect output light
A photodetector (10) and an output signal of the photodetector,
Display synchronized with the sampling light source and the light source to be measured
Means to do,  The sampling light source (4) includes a pulse light source and this pulse light source.
Luth light source output lightinputIsSaidFirst nonlinear optical material
And this first nonlinear optical materialOutputsSupercon
From Tinuum LightThe change of the output light frequency of the light source to be measured
Output light frequency of the sampling light source so as to follow
Adjust the numberTunable optical filter to select desired wavelength
An optical sampling optical waveform measuring apparatus characterized by including:
Place. Wherein an optical filter (9) which passes through the pre-Symbol second light nonlinear optical material to output the transmitted light of the optical filter (9) is introduced to the photodetector (10) The optical sampling optical waveform measuring device according to claim 1. 3. A polarization controller which is inserted into the output light path of the light source to be measured (2) and the output light path of the sampling light source (4) and applies polarization so as to match the second nonlinear optical material. The optical sampling optical waveform measuring device according to claim 2, further comprising: 4. The optical sampling optical waveform measuring apparatus according to claim 1, wherein the sampling light source includes a dispersion compensator for passing the super continuum light and shortening a pulse time width thereof. . 5. The optical sampling optical waveform measuring apparatus according to claim 1, wherein the first nonlinear optical material is configured as a material of a waveguide through which output light of the pulse light source passes.