JPH1075211A - Very high-speed light mixer system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain output light separated from two input beams by double wavelength difference Δλ(2Δλ). SOLUTION: A light mixer for using the probe light of wavelength λ1 and the pump light of wavelength λ2 as input light, synthesizing this light and generating the output light of wavelength λ5 separated from the wavelength of pump light for nΔλ (Δλ=≫λ1 -λ2 ≫) oppositely to the wavelength of probe light is provided to extract the signal of wavelength λ5 from the output by a band pass filter 3. A laser diode amplifier having the peak of output signal generation efficiency at the wavelength λ5 is used for the light mixer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to ultra-high-speed optical signal processing, and more particularly to an ultra-high-speed optical mixer for performing wavelength conversion at high speed.

[0002]

2. Description of the Related Art FIG. 1 shows a conventional ultra-high-speed optical mixer device.
This will be described with reference to FIG.

FIG. 12 is a block diagram showing a configuration of a conventional ultra-high-speed optical mixer device. In the following description, λ
_1, lambda ₂ · · · at the same time represents the wavelength, and represents the signal of the wavelength.

[0004] In the figure, reference numeral 11 denotes a multiplexing unit, which multiplexes two input signals λ ₁ and λ ₂ and mixes the input signals λ ₁ and λ _2.
Is output. Reference numeral 12 denotes a mixer unit, which uses a semiconductor laser amplifier, a difference frequency generator using a KTP crystal, or the like. The mixer section 12 receives the multiplexed signals λ ₁ and λ ₂ from the multiplexing section 11 as input signals, mixes the input signals, and converts the signals of wavelengths λ ₁ and λ ₂ and signals of λ ₃ and λ ₄ as shown in FIG. Output. Wavelength lambda _3, the signal of the lambda ₄ is the wavelength of the composite wave signal generated by the nonlinear optical effect, wavelength of the input signal lambda ₁
And λ ₂ , the difference between the two wavelengths Δλ (Δλ = | λ ₁ −
λ ₂ |). Reference numeral 13 denotes a band-pass filter (BPF), whose wavelength in the pass band is λ _{4 as shown} in FIG.

The operation of the conventional ultra-high-speed optical mixer shown in FIG. 12 will be described with reference to FIGS.

FIG. 3 is a waveform diagram for explaining functions and operations of the conventional example of FIG. 12, FIG. 4 is a block diagram showing functions and operations of the conventional example using a KTP crystal, and FIG. FIG. 7 is a diagram illustrating characteristics of a conventional mixer unit and a spectrum of an output wave.

[0007] multiplexing section 11, and the pumping light of the probe light and the wavelength lambda ₂ wavelength lambda ₁ is inputted. The pump light is excitation light for promoting a nonlinear optical effect, and the probe light is reference light. The multiplexing unit 11 multiplexes the two input signals,
The combined signal is output to mixer section 12.

As shown in FIG. 5 (a), the mixer section 12 to which the multiplexed signal is inputted has a wavelength λ ₃ whose wavelength is separated from the two input signals λ ₁ and λ ₂ by Δλ due to the nonlinear optical effect. And λ ₄ are output. In this case, as shown in FIG. 5 (c), a wavelength λ ₅ and a wavelength λ _{6 which} are separated from the two input signals by 2Δλ are generated as combined waves, but as shown in FIG. gain (gain) large near wavelengths lambda ₁ and wavelength lambda _2, since smaller in the vicinity of a wavelength lambda ₅ and wavelength lambda _6, composite wave component of the wavelength lambda ₅ and the wavelength lambda ₆ FIG 5 (c) As shown in the above, it is buried in the noise level and cannot be extracted as an output signal.

[0009] Bandpass filter 13 is a _quarter wavelength of the pass band lambda, the wavelength lambda _4, the wavelength of the two input signals to the opposite side from the wavelength lambda ₂ of the pump light and the wavelength lambda ₁ of the probe light The wavelengths are separated by the difference Δλ.

In this manner, the signal of the probe light having the wavelength λ ₁ is converted into an output optical signal having the wavelength λ ₄ .

Conventional mixers for performing wavelength conversion include the following.

First, a case where a semiconductor laser amplifier is used for a mixer will be described.

By inputting two input signals of wavelengths λ ₁ and λ ₂ , as shown in FIG. 3 (a), a difference Δλ = | λ ₁ −λ ₂ | Wavelength λ
₃ and λ ₄ are generated.

In this case, the mixer output λ ₃ or λ
₄ can be used, but since the wavelength is not so far from the input signal, as shown in FIG.
It is difficult to remove the input signals λ ₁ and λ ₂ even if the signals are filtered by a band pass filter having a pass band of ₄ .

Further, the peak of the gain characteristic of the semiconductor laser amplifier is near the wavelengths λ ₁ and λ ₂ of the two input signals, and the gain is low near the wavelength λ _{4 of the} output signal. Therefore, the conversion efficiency (output signal / input signal) is extremely small (10 ^-4 or less).

Next, the case where a KTP crystal is used for the mixer will be described.

As shown in FIG. 4A, when two input signals λ ₁ and λ ₂ are input to the KTP crystal 14 with spatial light, the wavelength-converted output signal λ ₄ is output as spatial light, Depending on the type and input method, the wavelength-converted output signal becomes a sum frequency, a difference frequency, or a second harmonic.

FIG. 4 shows the relationship between the input wavelength and the output wavelength (frequency) in this case.

FIG. 4B shows a case where the output signal is the sum of the frequencies of the wavelengths λ ₁ and λ ₂ of the _two input signals.

FIG. 4C shows a case where the output signal has a difference between the frequencies of the wavelengths λ ₁ and λ ₂ of the _two input signals.

FIG. 4D shows a case where the output signal is half the wavelength λ ₁ and λ ₂ of the two input signals.

In the case of using a KTP crystal, a certain dimensional size is required for processing with spatial light.
It is difficult to install as a device. Further, in the case of the difference frequency generation, as in the semiconductor laser amplifier, since the output wavelength is not so far from the input signal, it is difficult to remove the input signal with a filter.

Further, the nonlinear optical effect cannot be expected so much, and the output signal is small. Conversion efficiency (output signal /
Input signal) is extremely small (10 ^-5 or less).

[0024] As described above, the probe light of the wavelength lambda _1, the case of obtaining the output light of the wavelength lambda ₄ apart by the wavelength difference Δλ from the pump light of wavelength lambda _2, the band-pass filter when Δλ is small Even if this is used efficiently, and
It has been difficult to obtain an output signal by removing the input wave.

[0025] If the application to the measurement of the wavelength lambda ₁ of the probe light wavelength conversion from conventional using pump light of a known wavelength lambda _2, by generating output signals separated by the wavelength difference [Delta] [lambda], The output signal was being measured. In this case, when the two input wavelengths λ ₁ , λ ₂ and the output wavelength λ ₄ are close to each other, the input wave component included in the output cannot be completely removed, and the characteristics of the probe light cannot be obtained accurately. There was a defect.

[0026]

In a conventional semiconductor laser amplifier or mixer using KTP difference frequency generation, the conversion efficiency is low, so that it is necessary to increase the levels of pump light and probe light. It is difficult to remove them with a filter because they are close to each other, and it is necessary to increase the input signal in order to increase the output signal.

In a mixer using KTP sum frequency generation or KTP second harmonic generation in which the output wavelength is separated from the input wavelength band, it is easy to remove the input signal with a filter.
Since processing must be performed with spatial light, miniaturization is difficult, and the conversion efficiency is extremely low, which is not practical.

(1) In a conventional mixer using a semiconductor laser amplifier, the gain peak is matched to the input signal wavelengths λ ₁ and λ ₂ as shown in FIG. Amplified and a wavelength output Δλ = | λ ₂ −λ ₁ | In this wavelength characteristic, since the peak of the gain comes near the input wavelength, the gain decreases as the distance from the input wavelength increases, and the nonlinear optical effect hardly occurs. That: (integer of 2 or more n) separated output signal of lambda ₅ occurring in wavelength it is incorrectly buried under the noise, to use it therefore FIG 5 (c) as shown in nΔλ Could not.

[0029]

According to the present invention SUMMARY OF ultrafast optical mixer device receives the probe light of the wavelength lambda ₁ and wavelength lambda ₂ of pump light, a multiplexing unit 1 for multiplexing, the multiplexing When the output of the unit 1 is received and the wavelength difference between the probe light and the pump light is defined as Δλ, the wavelength λ _{5 is} separated from the wavelength of the pump light by nΔλ (n: an integer of 2 or more) on the opposite side to the wavelength of the probe light. a mixer unit 2 for generating a combined output, receives the output of the mixer unit 2, is made of a band-pass filter 3 for selecting the combined output of the wavelength lambda ₅ output.

Further, the mixer section 2 calculates the peak of the signal generation efficiency by the wavelength λ _{2 of the} pump light and the wavelength λ ₅ of the combined output.
It is composed of laser diode amplifiers at various locations.

Further, the mixer section 2 is a quantum well type laser diode amplifier 20 having two peaks of signal generation efficiency at the wavelength λ _{2 of the} pump light and the wavelength λ ₅ of the combined output. It is.

Further, the quantum well laser diode amplifier 20 has a multilayer quantum well structure and end face mirrors 21a and 21b provided at both ends of the multilayer quantum well structure. The layer thickness of at least one layer and the energy level of the quantum well are formed to be different from the layer thickness of the other layer and the energy level of the quantum well, and the reflectivity of the end face mirrors 21a and 21b is 1
/ 1000 to 1/100000.

[0033]

In DETAILED DESCRIPTION OF THE INVENTION The present invention, Enuderutaramuda from an input wave signal (n: 2 or more integer) apart output wavelength lambda ₅
, The input signal can be easily removed.

The peak of the signal generation efficiency of the laser diode amplifier is determined by comparing the wavelength λ _{2 of the} pump light with the wavelength λ _{5 of the} output light.
Since these two locations are provided, it is possible to reduce the influence of the wavelength λ ₄ outputted at a distance of Δλ from the input wave signal.

Furthermore, the size can be made smaller than that using a KTP crystal, and the conversion efficiency is extremely high (10 ^-2 or more).

[0036]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

In this figure, reference numeral 1 denotes a multiplexing unit, which multiplexes two input signals λ ₁ and λ ₂ and outputs the multiplexed signals λ ₁ and λ ₂
Is output. 2 is a mixer unit, which receives the multiplexed signals λ ₁ and λ ₂ from the multiplexing unit 1 as input signals and mixes them.
Amplify, as shown in FIG. 6, the wavelengths λ ₁ , λ ₂ and λ ₃ ,
The signals of λ ₄ and λ ₅ are output. Wavelengths λ ₃ , λ ₄ and λ
The signal ₅ is a composite wave signal generated by the nonlinear optical effect. From the wavelengths λ ₁ and λ _{2 of} the input signal, the difference Δλ between two wavelengths (Δλ = | λ ₁ −λ ₂ |) and nΔλ
(N: an integer of 2 or more; the same applies hereinafter). 3 is a band pass filter (BPF);
(C), the wavelength of the passband is lambda _5.

Next, the operation of the ultrahigh-speed optical mixer device in the embodiment of FIG. 1 will be described with reference to FIGS. 2, 6 and 11.

FIG. 2 is a waveform diagram for explaining the function and operation of the embodiment of FIG. 1, FIG. 6 is a diagram showing the characteristics of the mixer section of the present invention and the spectrum of the output wave, and FIG.
FIG. 6 is a diagram illustrating an output of a quantum well laser diode amplifier and a diagram illustrating characteristics of a bandpass filter according to one embodiment.

[0040] multiplexing section 1, and the pumping light of the probe light and the wavelength lambda ₂ wavelength lambda ₁ is inputted. The pump light excites the nonlinear optical effect, and the probe light (also referred to as reference light) attempts to convert its wavelength from now on. The multiplexing unit 1 multiplexes the two input signals and outputs the multiplexed signal to the mixer unit 2.

The mixer 2 to which the multiplexed signal has been input is as shown in FIG.
As shown in (a), due to the nonlinear optical effect, a composite wave signal of wavelengths λ ₃ and λ ₄ whose wavelengths are separated by Δλ from _two input signals λ ₁ and λ _2, and a wavelength which is nΔλ away from the two input signals, respectively. λ ₅ and wavelength λ ₆ are generated as a composite wave.

The gain of the mixer section 2 (Gain) is, in the conventional example has a peak around a wavelength lambda ₁ and wavelength lambda _2, since the smaller in the vicinity of a wavelength lambda ₅ and wavelength lambda _6, the wavelength lambda ₅ and The synthesized wave component of the wavelength λ ₆ is buried in the noise level and cannot be extracted as an output signal. However, in this embodiment, the peak is shifted toward the wavelength λ ₅ as shown in FIG. The wavelength λ ₅ can be output as a composite wave signal.

[0043] Further, since also possible to adjust the peak of the signal generation efficiency to the wavelength lambda _5, as a very high mixer conversion efficiency, it is possible to obtain a very large output signal.

As shown in FIG. 11, the bandpass filter 3 has a passband wavelength of λ ₅ , and this wavelength λ ₅
Is a wavelength separated from the wavelength λ ₁ of the probe light by nΔλ which is n times the wavelength difference Δλ of the two input signals on the opposite side to the wavelength λ _{2 of the} pump light.

As described above, the signal of the probe light having the wavelength λ ₁ is converted into the output signal having the wavelength λ ₅ .

In the laser diode amplifier used as the mixer unit 2 in this embodiment, the peak characteristics of the output signal generation efficiency are provided on the wavelengths λ ₄ and λ _{5 in} order to extract the wavelength λ ₅ .

(1) As an example, as shown in FIG. 6B, the characteristics of the peak of the output signal generation efficiency are represented by wavelengths λ ₄ and λ _5.
Side, a signal separated by nΔλ can be taken out. At this time, the output on the wavelength λ ₃ side becomes small, but this is not used.
_4, there is no problem because it uses only λ ₅ side.

(2) In another example, as shown in FIGS. 2A and 2B, the output signal generation efficiency of the mixer section 2 has two peak characteristics. Also to have a peak of an output signal generation efficiency at a wavelength lambda _5.

Here, a conventional optical amplifier having a wide wavelength range will be described with reference to Japanese Patent Application Laid-Open No. 6-283824.

In the invention of the optical amplifying device according to this application, the active region is formed by an optical confinement layer, a plurality of quantum well layers, and a barrier layer in contact with the quantum well layer between the quantum well layers,
At least one of the plurality of quantum well layers has a thickness different from that of the other layers, and has a lattice mismatch. Then, by adjusting the layer thickness and the amount of strain of the plurality of quantum well layers, 1.1.5 in the 1.5 μm wave band.
An example of amplifying a wavelength of 45 μm to 1.54 μm is disclosed.

It is conceivable that this optical amplifying element is used as the mixer section 2 in FIG. 1. A quantum well laser diode amplifier having two peak characteristics in output signal generation efficiency applied to the present invention is shown in FIG. This will be described with reference to FIG.

FIG. 7 is a diagram for explaining an energy level of a laser diode amplifier used in a mixer unit suitable for implementing the present invention. FIG. 8 shows an embodiment of the present invention. FIG. 2 is a block diagram using a type laser diode amplifier.

As shown in FIG. 7, the amount of injected carriers is increased to accumulate energy to a level higher than the energy level of the conventional laser diode amplifier to perform mixing and amplification.

By lowering the reflectance of the end face mirror 21 shown in FIG. 8 described later, the loss increases, the laser beam does not oscillate unless a larger amount of energy is injected than in the conventional case, and the wavelength becomes longer due to the increased energy. .

The higher the energy level, the higher the output signal generation efficiency at a wavelength farther from the original peak. FIG.
As shown in (b), the laser diode amplifier having the second peak has a second output signal generation efficiency peak at λ ₅ by adjusting the layer thickness to match the wavelength at the time of manufacture.

That is, in a laser diode amplifier having a plurality of layers, the layer thickness is adjusted for each layer, and the signal generation efficiency peaks at the wavelength having the peak at the lowest level and the wavelength having the peak at the second level. , It is possible to increase the bandwidth.

Generally, in a pn junction laser diode amplifier, the energy gap Eg between the conduction band and the valence band
And the frequency ν of the light emitted therefrom has a relationship of hν = Eg as Planck constant h, so that the layer of the pn junction is set so that the wavelength of the light output from the laser diode amplifier becomes λ _5. The thickness of the energy gap Eg
To match.

In a normal laser diode amplifier, when the reflectivity of the end face mirror is reduced to less than 1/1000, carriers are injected and energy is accumulated, amplification and oscillation occur when the lowest level is reached. In the laser diode amplifier, the reflectance of the end face mirror 21 shown in FIG.
The threshold value for amplification and oscillation is increased by suppressing the threshold to about / 1000 to 1 / 100,000, and oscillation is started when the desired layer reaches the second level as shown in FIG.

Next, a quantum well laser diode amplifier suitable for the mixer unit 2 will be described with reference to FIGS.

In a quantum well laser diode amplifier, an active layer in which two kinds of composition materials are alternately laminated is used.

FIG. 8 uses a quantum well type laser diode amplifier 20 as the mixer section 2 of FIG.

This quantum well laser diode amplifier 2
0 is an end face mirror 21a at both ends, as shown in FIG.
21b is provided, and an active layer composed of a hetero-junction quantum well type structure 22 in which two kinds of composition materials are alternately laminated is disposed therebetween. 23 is a power supply for carrier injection. FIG. 10 is a diagram illustrating an energy band of the quantum well laser diode amplifier 20 of FIG.

As described above, in the quantum well type structure in which ultra-thin films of two different materials are alternately stacked, electrons are stable in a low state, so that the energy distribution at the bottom of the conduction band is low in the potential well layer. Can be localized.
The potential barrier layer acts as a barrier because the energy at the bottom of the conduction band is high. Since only the wave number of a standing wave is allowed for electrons bound to the potential well layer, the wavelength is determined by the layer thickness. Therefore, it is only necessary to adjust the layer thickness so that the light has a desired wavelength.

In the quantum well laser diode amplifier 20 configured as described above, electrons are stable at low energy. As energy is injected, the potential well layer in FIG. 10 accumulates, and when the layer is saturated, oscillation normally occurs. The quantum well laser diode amplifier 20 does not oscillate here but oscillates when it reaches the next energy level by suppressing the reflectivity of the end face mirrors 21a and 21b to about 1 / 10,000.

By arranging this potential well layer in multiple layers and changing some layer thicknesses and energy levels of the quantum wells, oscillation can be performed at a plurality of wavelengths.

FIG. 9 is a diagram showing the state density of the quantum well laser diode amplifier of FIG.

In this case, the state density takes a step-like value as shown in FIG. 9, injects carriers, accumulates energy up to the second level, and oscillates. At this time, since the energy has a value four times as large as that at the lowest level, the wavelength can be set far apart from the wavelength adjustment by the normal layer thickness.

Quantum Well Laser Diode Amplifier 20
Shows the energy band structure shown in FIG. 10, and tends to oscillate in an energy gap between the lowest point of the conduction band of the potential well layer and the highest point of the valence band. However, electrons cannot exist at the lowest energy of the conduction band in the potential well layer due to the quantum effect.
It can exist only when a standing wave stands in the potential well layer. The energy level when the wave number of the standing wave is the lowest is called the lowest level. When the wave of the standing wave increases, the energy level that an electron can take becomes n ² (n: natural number) times the lowest level. Value. Similarly, in the valence band, the energy level that a hole can take is only at the energy at which a standing wave is generated, and is n ² times the lowest level.

As an example, the thicknesses of the potential well layer and the potential barrier layer are each 1 μm, and the energy gap of the potential barrier layer is 0.1 μm on the valence band side.
24 eV and 1.35 eV on the conduction band side. Further, the wavelength based on the energy gap Eg between the lowest energy of the potential well layer in the conduction band and the highest energy in the valence band is 1600 nm. In this case, the energy at the lowest level is energy corresponding to a wavelength of 30 nm on the conduction band side, and is energy corresponding to a wavelength of 5 nm in the valence band. Accordingly, the wavelengths of the oscillation at the lowest level and the oscillation at the second level are as follows.

(Oscillation by lowest level) 1600− (30 + 5) = 1565 nm (Oscillation by second level) 1600− (30 × 2 ² + 5 × 2 ² ) = 1460 nm Thus, each active layer of the quantum well Minimize the reflectance of the end mirrors 21a and 21b (1/1000 to 1/1).
00000), it is possible to obtain a high-bandwidth quantum well laser diode amplifier having a high signal generation rate by oscillating at the lowest level and the second level.

As described above, it is possible to set a wider range than the conventional wavelength setting by adjusting the layer thickness at the lowest level. The wavelength λ _{1 of the} probe light, the wavelength λ _{2 of the} pump light, and the wavelength λ _{5 of the} combined output are obtained. Can be handled even if they are far away.

This quantum well type laser diode amplifier 2
2 (a) and FIG. 11 show output spectra of the mixer unit 2 using 0. Probe light wavelength λ ₁ = 1553n
m, when the wavelength of the pump light λ ₂ = 1548 nm is input, and the output of n = 2 is taken out, the output wavelength λ ₅ becomes λ ₅ =
It is 1538 nm, which indicates that unnecessary wavelength output such as pump light having a wavelength λ ₂ = 1548 nm can be removed when the filter band is about 3 nm or less.

The signal generation efficiency when the multilayer quantum well laser diode amplifier thus configured is used as the mixer section 2 is shown in FIG. 2 (b), where two input wavelengths λ ₁ and λ _{2 are used.} Λ ₅
It is possible to give a peak due to the second level at the wavelength λ ₅ of the combined output by setting the position slightly shifted to the side.

[0074] The ultra-high speed optical mixer device, such as using the optical sampling by the pump light in pulse form, can be utilized such as that observed by converting the wavelength lambda ₁ of the probe light in a wavelength lambda ₅ of the output light .

In the above embodiment, the case where the wavelength λ _{2 of the} pump light is smaller than the wavelength λ _{1 of the} probe light and the wavelength λ _{5 of the} output light is smaller than the wavelength λ _{2 of the} pump light has been described. Also, when the wavelength λ _{2 of the} pump light is larger than the wavelength λ _{1 of the} probe light and the wavelength λ _{5 of the} output light is larger than the wavelength λ _{2 of the} pump light, the peak of the gain of the mixer section due to the lowest level and the second level It is needless to say that the present invention can be applied by exchanging the peak of the gain of the mixer section due to the above.

[0076]

As described above in detail, the ultra-high-speed optical mixer of the present invention is capable of providing the probe light having the wavelength λ ₁ and the wavelength λ ₂
When the wavelength difference between the probe light and the pump light is set to Δλ, the wavelength of the probe light is calculated from the wavelength of the pump light. A mixer unit 2 for generating a combined output of a wavelength λ ₅ separated by nΔλ (n: an integer of 2 or more) on the opposite side to the wavelength of the above, receiving the output of the mixer unit 2 and selecting and outputting the combined output of the wavelength λ ₅ And the wavelength λ _{1 of} the pump light and the wavelength λ _{2 of the} pump light,
Since it is possible to obtain a mixer output having a wavelength λ _{5 which is} twice as long, even if the wavelength λ _{1 of the} probe light and the wavelength λ _{2 of the} pump light are close to each other, the probe light and the pump light can be easily eliminated by the filter. The wavelength can be cut, and high quality output light can be obtained.

Further, according to the present invention, the mixer section 2 is composed of laser diode amplifiers having two peaks of signal generation efficiency at the wavelength λ _{2 of the} pump light and the wavelength λ ₅ of the combined output. The output of ₅ can be more easily extracted from the input optical signal by the band pass filter.

According to the present invention, the mixer 2 further comprises:
Since the quantum well laser diode amplifier 20 has two peaks of signal generation efficiency at the wavelength λ _{2 of the} pump light and the wavelength λ ₅ of the combined output, the peak of the signal generation efficiency is set at two positions. And an extremely high output signal can be obtained.

According to the present invention, the quantum well type laser diode amplifier 20 comprises a multilayer quantum well structure and end mirrors 21 provided at both ends of the multilayer quantum well structure.
a and 21b, wherein the layer thickness of at least one layer and the energy level of the quantum well of the multilayer quantum well structure are different from the layer thickness of the other layer and the energy level of the quantum well, And the end mirrors 21a, 21b
Is characterized by a reflectance of 1/1000 to 1/100000, so that even if the input wavelengths λ ₁ and λ ₂ and the combined output wavelength λ ₅ are far apart, those wavelengths can be easily obtained. , And a high quality output light can be obtained.

When the pump light is used as the gate signal, the probe light can be wavelength-converted and observed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a waveform chart for explaining functions and operations of the embodiment of FIG. 1;

FIG. 3 is a waveform chart for explaining functions and operations of the conventional example of FIG.

FIG. 4 is a block diagram showing a conventional example using a KTP crystal and a diagram for explaining functions and operations.

FIG. 5 is a diagram illustrating characteristics of a conventional mixer unit and a spectrum of an output wave.

FIG. 6 is a diagram illustrating characteristics of a mixer unit of the present invention and a spectrum of an output wave.

FIG. 7 is a diagram for explaining an energy level of a laser diode amplifier used in a mixer unit suitable for implementing the present invention.

FIG. 8 is a block diagram illustrating a mixer unit using a quantum well laser diode amplifier according to an embodiment of the present invention.

9 is a diagram illustrating a state density of the quantum well laser diode amplifier in FIG.

FIG. 10 is a diagram illustrating an energy band of the quantum well laser diode amplifier of FIG.

FIG. 11 is a diagram illustrating an output of the quantum well laser diode amplifier and a diagram illustrating characteristics of a bandpass filter in the embodiment of FIG. 8;

FIG. 12 is a block diagram showing a configuration of a conventional ultra-high-speed optical mixer device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 multiplexing section 2 mixer section 3 bandpass filter 20 quantum well laser diode amplifier

Claims (4)

[Claims] 1. A inputs the wavelength lambda ₁ of the probe light and the wavelength lambda ₂ of pump light multiplexing unit for multiplexing and (1), receives the output of the multiplexing section (1), and the probe light when the wavelength difference of the pump light was set to Δλ, nΔλ from the wavelength of the pump light on the opposite side of the wavelength of the probe light (n: 2 or more integer) mixer unit for generating a synthesized output of remote wavelength lambda ₅ (2) When receives an output of the mixer unit (2), the wavelength λ bandpass filter (3) for combining outputs selects the output of ₅ and ultrafast optical mixer device having a. 2. The mixer section (2) determines the peak of the signal generation efficiency by the wavelength λ _{2 of the} pump light and the wavelength λ ₅ of the combined output.
2. The ultra-high-speed optical mixer device according to claim 1, wherein the ultra-high-speed optical mixer device is constituted by laser diode amplifiers provided at different locations. 3. The mixer section (2) determines the peak of the signal generation efficiency by the wavelength λ _{2 of the} pump light and the wavelength λ ₅ of the combined output.
-Well type laser diode amplifiers in 20 places (20)
2. The ultra-high-speed optical mixer device according to claim 1, wherein 4. The quantum well laser diode amplifier (20) includes a multilayer quantum well structure and end face mirrors (21a, 21b) provided at both ends of the multilayer quantum well structure.
Wherein the layer thickness and the energy level of the quantum well of at least one layer of the multilayer quantum well structure are formed so as to be different from the layer thickness and the energy level of the quantum well of the other layer, and The reflectivity of the end mirror is 1 / 1000-
The ultrahigh-speed optical mixer device according to claim 3, wherein the ratio is 1/100000.