JP2002043683A - Shg laser source control parameter calculation device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize an SHG laser source control parameter calculation device and a method capable of easily obtaining control parameters which enable an SHG laser source to output a high laser power. SOLUTION: An SHG laser source is equipped with a semiconductor laser possessed of an active part, a phase part, and a DBR part, and an SHG device which outputs second harmonic light by changing light originated from the semiconductor laser in wavelength, and the control parameters of the second harmonic light of high power of the SHG laser source are obtained through a control parameter calculation device. The control parameter calculation device is equipped with a photodetector which receives the second harmonic light outputted from the SHG device and converts it into electric signals. Further, the device has a control parameter decision means which obtains the output power change point of second harmonic light, changes a DBR drive current and a phase control current at the center of a change point on a minus and a plus side, and obtains a DBR drive current and a phase control current of the second harmonic light of high output power through the same procedure as in the output power change point by electrical signals outputted from the photodetector.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an SHG laser light source control parameter calculating apparatus and a SHG laser light source control parameter calculating method capable of easily obtaining control parameters for obtaining a high output power of an SHG laser light source. It is.

[0002]

2. Description of the Related Art In recent years, as the recording capacity of an optical disk has increased, the areal recording density on the disk has increased, and the size of the condensed spot on the disk has decreased. For this reason, light of a light source used for recording and reading of a disc is also required to have a short wavelength. As a light source that generates such short-wavelength light, there is an SHG (second harmonic generation) laser light source. The SHG laser light source is disclosed in, for example,
As described in Japanese Patent No. 6861 or the like, fundamental wave light is incident on a nonlinear optical crystal to generate second harmonic light, thereby obtaining short-wavelength coherent light. Such an apparatus is shown and described in FIG.

In FIG. 11, a distributed reflection type (DBR; di
The semiconductor laser 1 includes an active part 11, a phase part 12, and a DBR part 13 in which a diffraction grating (distributed Bragg reflector (DBR)) is formed, and generates a fundamental wave light.

[0004] The active portion 11 generates a fundamental wave light when a current is injected. The phase section 12 controls the temperature of the region by flowing a current perpendicular to the pn junction or by flowing a current to the thin film heater, and changes the refractive index of the waveguide by this temperature change, thereby forming a DBR semiconductor laser. The phase of the fundamental light within 1 is adjusted to change the oscillation wavelength. The DBR unit 13 is connected to the active unit 11 via the phase unit 12.
, And a current is caused to flow perpendicular to the pn junction, or by flowing a current to the thin film heater,
The temperature of the region is controlled, and the change in temperature changes the refractive index of the waveguide, adjusts the reflection characteristics of the diffraction grating, and changes the oscillation wavelength.

The SHG element 2 receives the fundamental light, converts the wavelength of the fundamental light, and outputs the second harmonic light (blue light). The SHG element 2 forms a periodically domain-inverted region 22 on a LiNbO ₃ substrate 21. Next, the optical waveguide 23 is formed. Further, a protective film 24 is formed, and the SHG element 2 is manufactured.

[0006] The photodetector 3 receives the second harmonic light and converts it into an electric signal. The current control circuit 4 determines the phase control current of the phase unit 12 based on the electric signal from the photodetector 3,
It outputs a DBR drive current of the BR unit 13.

The operation of such a device will be described below.
The active portion 11 of the DBR semiconductor laser 1 is driven by supplying an LD drive current, and the DBR semiconductor laser 1 outputs a fundamental light. The fundamental wave light is input to the SHG element 2, the wavelength is converted, and the second harmonic light is output. The second harmonic light is converted into an electric signal by the photodetector 3. And the current control circuit 4
Outputs a phase control current and a DBR driving current based on the electric signal, and adjusts the wavelength of the fundamental light of the DBR semiconductor laser 1.

[0008]

When the SHG element 2 receives light of a specific wavelength, the SHG element 2 receives a second harmonic (1 of the input wavelength).
/ 2 wavelength light). But,
As shown in FIG. 12, the SHG element 2 has a limited wavelength range in which high output power is obtained, and the wavelength range differs for each SHG element 2. Further, similarly to the case where the wavelength range is different for each SHG element 2, even if the current value applied to the DBR semiconductor laser 1 is the same, the output wavelength is different. For this reason, the control parameter of the current value given to the DBR semiconductor laser 1 has to be obtained for each SHG laser light source.

For this reason, a current value to be applied to the DBR semiconductor laser 1 is obtained using a measuring instrument such as an optical spectrumr or an optical wavelength meter. However, an optimum control parameter must be obtained from all control parameters. In addition, since these must be obtained for each SHG laser light source, there is a problem that work efficiency is poor.

Accordingly, an object of the present invention is to realize an SHG laser light source control parameter calculating apparatus and a SHG laser light source control parameter calculating method capable of easily obtaining a control parameter capable of outputting a high output power of the SHG laser light source. It is in.

[0011]

SUMMARY OF THE INVENTION The present invention relates to a D / A converter having an active portion, a phase portion, and a distributed Bragg reflector (DBR).
A control parameter of high output power of second harmonic light in an SHG laser light source including a semiconductor laser having a BR section and an SHG element that performs wavelength conversion of light of the semiconductor laser and outputs second harmonic light A control parameter calculation device, comprising: a photodetector that receives second harmonic light output from the SHG element and converts the second harmonic light into an electric signal;
A change point of the output power of the second harmonic light is obtained from an electric signal from the photodetector by changing a DBR drive current supplied to the BR section and a phase control current supplied to the phase section. At the center of the point, the DBR drive current,
Control parameter determining means for changing a phase control current and obtaining a DBR drive current of a high output power of the second harmonic light and a phase control current based on an electric signal from the photodetector. .

Further, the present invention provides a semiconductor laser having an active part, a phase part, and a DBR part having a distributed Bragg reflector (DBR) formed thereon, and the wavelength conversion of light of the semiconductor laser is performed. A control parameter calculating method for obtaining a control parameter of a high output power of a second harmonic light in an SHG laser light source including an SHG element for outputting a harmonic light, wherein a DBR driving current to be provided to the DBR section and a control parameter to be provided to the phase section The phase control current is changed to determine the change point of the output power of the second harmonic light, and the phase control current and the DBR drive current are changed at the center of the change point on the minus side and the plus side to obtain a high output of the second harmonic light. A power DBR drive current and a phase control current are obtained.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing one embodiment of the present invention. Here, the same components as those in FIG. 11 are denoted by the same reference numerals, and description thereof is omitted. In the SHG laser light source, the fundamental light is usually infrared light (wavelength: about 850 nm),
Since the second harmonic light is blue light (wavelength: about 425 nm), the second harmonic light will be described as blue light.

In the figure, a control unit 8 has a provisional control parameter calculation unit 81, a current ratio calculation unit 82, and a control parameter determination unit 83, receives an electric signal from the photodetector 3, A drive current is supplied, a phase control current is supplied to the phase unit 12, and a DBR drive current is supplied to the DBR unit 13 to control the DBR semiconductor laser 1.

The provisional control parameter calculating means 81 changes the DBR drive current and the phase control current at desired intervals while keeping the LD drive current constant, and uses the electric signal from the photodetector 3 to
The DBR drive current and the phase control current of the temporary maximum value of the blue light are obtained.

The current ratio calculating means 82 keeps the LD driving current constant, changes the DBR driving current and the phase control current based on the DBR driving current and the phase control current of the provisional control parameter calculating means 81, and From the electric signal from the CPU, the DBR drive current and the phase control current at the change point of the blue light are obtained,
The current ratio between the DBR drive current and the phase control current is obtained from this change point.

The control parameter determining means 83 keeps the LD drive current constant, and calculates the DB by the current ratio of the current ratio calculating means 82.
The R drive current and the phase control current are changed at the center of the change points on the minus side and the plus side, and the DBR drive current and the phase control current of high output power of blue light are obtained from the electric signal from the photodetector 3.

The operation of such a device will be described below.
First, the relationship between the DBR drive current, the phase control current, and the blue light output power will be described. 2 and 3 are diagrams showing the relationship among the DBR drive current Idbr, the phase control current Iph, and the blue light output power, and FIG. 3 is an enlarged view of FIG. Here, the DBR drive current Idbr is 0x0000 to 0x0.
FFF (0 to about 120 mA) and phase control current Iph
0x0000 to 0x0FFF (0 to about 60 mA). Note that 0x is a symbol indicating a hexadecimal number, and the scale in FIGS. 2 and 3 is a decimal number.

As is apparent from FIG. 2, the output of blue light is limited to a certain range.
2, the DBR drive current Idbr is 0x0 to 0x
Blue light is output only in the range of 300.

Next, FIG. 3 will be described with reference to FIG. 3, which is an enlarged view of the portion of FIG. 2 where the blue light output power is strongly output. As shown in FIG. 3, the blue light output power is
The DBR drive current Idbr has a distribution like a mountain having a width between b and c. Here, straight lines b and c
Is a linear approximation of a change point where the output power of blue light is largely changed. When the phase control current is fixed and the DBR driving current is changed, the region in FIG. 3 can be represented as shown in FIG. The scale in FIG.
It is a decimal number.

In FIG. 3, the apex of the peak is located almost in the middle between the straight lines b and c.
Depending on the combination of the G elements 2, it may be close to the straight lines b and c. In such a case, when the control parameter of the maximum output power is obtained from the peak of the mountain, the output power becomes unstable. Therefore, the current value having the maximum power on the straight line a between the straight lines b and c is defined as the maximum output power (high output power). The current value at this time is defined as a pole current.

Taking advantage of this, control parameters are obtained as follows. FIG. 5 is a flowchart showing a schematic operation of the apparatus shown in FIG.

The provisional control parameter calculation means 81 determines that the LD drive current is constant and the DBR applied to the DBR semiconductor laser 1
The drive current and the phase control current are changed, and the DBR drive current I at which the blue light is maximized by the electric signal from the photodetector 3
An approximate value of dbr (Max_Idbr1) is obtained (step 1).

Next, the provisional control parameter calculating means 81
DBR driving current “Max_Idbr1”
The R drive current and the phase control current are changed, and a combination of the DBR drive current and the phase control current (Max_Idbr2,
Max_Iph2) is obtained (step 2).

The current ratio calculating means 82 outputs the DBR driving current “
Max_Idbr2 ”, phase control current“ Max_Iph
The DBR drive current and the phase control current are changed in detail around 2 ″, and the current ratio ΔIph: ΔIdbr is obtained from the change point of the blue light output power based on the electric signal from the photodetector 3 (step 3).

The control parameter determining means 83 calculates the current ratio Δ
Iph: A pole current is obtained from ΔIdbr (step 4).

Further, each step will be described in detail with reference to flowcharts shown in FIGS. FIG.
0 illustrates the operation of the apparatus shown in FIG.

(Step 1) The range of the limited DBR drive current Idbr for outputting blue light is specified.

The provisional control parameter calculating means 81 sets the phase control current Iph to "0" (S11). It is determined whether the phase control current Iph is equal to or less than "0xFFF" (S1).
2).

When the phase control current Iph is equal to or less than "0xFFF", the DBR drive current Idbr is set to "0" (S13). DBR drive current Idbr is “0xFFF”
It is determined whether it is below (S14).

The DBR drive current Idbr is "0xFFF"
In the following cases, it is determined whether the electric signal from the photodetector 3 is maximum (S15). At the maximum, this DBR drive current value is set to Max_Idbr1, and the DBR drive current Idbr
Is added to "0x20" (S16, S17). If it is not the maximum, "0x20" is added to the DBR drive current Idbr (S17). Then, again, the DBR drive current Idbr
Is determined to be equal to or less than "0xFFF" (S14).

When the DBR drive current Idbr is "0xFFF"
Otherwise, the phase control current Iph is set to “0x400”.
Is added (S18). Then, again, the phase control current Ip
It is determined whether h is equal to or less than "0xFFF" (S12).

When the phase control current Iph is not equal to or less than "0xFFF", the processing of step 1 is terminated.

That is, the phase control current Iph is set to 0x0,0
x400, 0x800, 0xc00 respectively,
The DBR drive current Idbr is set to 32 from 0x0 to 0xFFF.
The DBR drive current Idbr at which the blue light output power is maximized is determined by setting the stages. This DBR drive current Idbr
Blue light is output in the vicinity.

(Step 2) The change range of the DBR drive current and the phase control current is narrowed, and the DBR drive current and the phase control current that maximize the blue light are further specified. In addition, in order to control the blue light output power, there is a high possibility that the phase control current Iph becomes uncontrollable near 0x0 and 0xFFF.
0 to 0xE00 ".

The temporary control parameter calculation means 81 sets the phase control current Iph to "0x200" (S21).
It is determined whether the phase control current Iph is equal to or less than "0xE00" (S22).

When the phase control current Iph is equal to or less than "0xE00", the DBR drive current Idbr is changed to "Max_Idbr".
1-0x200 "(S23). It is determined whether the DBR drive current Idbr is equal to or less than" Max_Idbr1 + 0x200 "(S24).

When the DBR drive current Idbr is "Max_Id"
When br1 + 0x200 "or less, it is determined whether the electric signal from the photodetector 3 is the maximum (S25). When the electric signal is the maximum, the DBR drive current value is set to Max_Idbr2, the phase control current is set to Max_Iph2, and the DBR drive current Id is set.
"0x20" is added to br (S26, S27). If it is not the maximum, "0x20" is added to the DBR drive current Idbr (S27). Then, again, the DBR drive current Id
It is determined whether br is equal to or less than “Max_Idbr1 + 0x200” (S24).

When the DBR drive current Idbr is "Max_Id"
br1 + 0x200 "or less, the phase control current I
"0x20" is added to ph (S28). Then, it is determined again whether the phase control current Iph is equal to or less than "0xE00" (S22).

When the phase control current Iph is not equal to or less than "0xE00", the processing in step 2 is terminated.

That is, the phase control current Iph is set to “0x20
32 steps within the range of 0 to 0xE00, and the DBR drive current Idbr is changed to "Max_Idbr1-0x200 to
Max_Idbr1 + 0x200 ″ is changed in 32 steps, and the DBR drive current Id at which the blue light output power is maximized
br and a phase control current Iph. The blue light having the maximum power is output near the DBR drive current Idbr and the phase control current Iph.

(Step 3) The change point of the blue light output power is determined, the range of the blue light output power is specified, and the DBR
Find the current ratio between the drive current and the phase control current.

The current ratio calculating means 82 calculates the phase control current Ip
h is set to “Max_Iph2-0x100” (S
301). When the phase control current Iph is “Max_Iph2 +
It is determined whether it is 0x100 "or less (S302).

When the phase control current Iph is "Max_Iph2"
+ 0 × 100 ″ or less, the DBR drive current Idbr
Is set to “Max_Idbr2-0x200” (S
303). When the DBR drive current Idbr is “Max_Idb”
It is determined whether or not r2 + 0x200 "or less (S304).

The DBR drive current Idbr is "Max_Id"
When br2 + 0x200 "or less, the value of the electric signal from the photodetector 3 is stored, and the DBR drive current Idbr is set to" 0x
10 "(S305, S306), and the DBR drive current Idbr is again changed to" Max_Idbr2 +
It is determined whether it is 0x200 "or less (S304).

When the DBR drive current Idbr is “Max_Id”
br2 + 0x200 "or less, the phase control current I
“0x8” is added to ph (S307). Then, again, the phase control current Iph becomes “Max_Iph2 + 0x1”.
00 "or less (S302).

When the phase control current Iph is "Max_Iph2"
If not less than + 0x100 ", the maximum value of the change amount of the blue light output power with respect to the change of the DBR drive current Idbr when the phase control current Iph is fixed is obtained (S30).
8). Then, the maximum value of the change amount of the blue light output power, 2
The change amount is set as a threshold value at 0% (S309).

The DBR of the stored blue light output power at the head
The drive current Idbr and the phase control current Iph are set (S
310). It is determined whether all the stored power data have been checked (S311).

When not checking all power data,
It is determined whether the absolute value of the difference between the blue light output powers exceeds a threshold (S312).

If it exceeds the threshold value, it is determined whether the difference in blue light output power is positive or negative (S313).

When the difference between the blue light output powers is positive, it is determined whether or not the amount of change is the maximum with the same phase control current Iph, and if it is the maximum, the DBR drive current Idbr and the phase control current Iph
Is stored as plus side data, and proceeds to the next processing. If the data is not the maximum, the processing proceeds to the next processing (S314, S31
5).

When the difference between the blue light output powers is negative, it is determined whether the amount of change is the maximum with the same phase control current Iph, and if it is the maximum, the DBR drive current Idbr and the phase control current Iph
Is saved as negative data, and proceed to the next process.
If it is not the maximum, the process proceeds to the next process (S316, S31
7).

Then, the DBR drive current Idbr and the phase control current Iph of the next stored blue light output power are set (S318). It is determined again whether all the stored power data have been checked (S311).

When all the power data have been examined, a linear approximation is obtained for each of the plus side data and the minus side data by the least square method (S319). It is determined which of the plus side data and the minus side data is larger (S32
0). If there are many positive sides, the slope of the straight line on the positive side is set as the current ratio ΔIph: ΔIdbr (S321). When the slope of the minus side straight line is large, the slope of the minus side straight line is set as the current ratio ΔIph: ΔIdbr (S322).

That is, the phase control current Iph is set to “Max_
Iph2-0x100 to Max_Iph2 + 0x10
0 ”to the DBR drive current Idbr
To “Max_Idbr2-0x200 to Max_Idb
r2 + 0x200 ″ is changed in 16 steps, and the blue light output power is stored. From the stored blue light output power, the maximum change point indicated by ● in FIG. 10 is calculated. Has the maximum value of the output power, and the current ratio is determined from the maximum change point.

(Step 4) The width of the change point of the blue light output power is obtained, and the DBR drive current and the phase control current are changed at the center of the width using the current ratio to obtain the pole current.

The control parameter determining means 83 sets the leading phase control current Iph of the plus side data stored by the current ratio calculating means 82 (S41). It is determined whether all the stored plus side data have been checked (S42).

If all the plus side data have not been checked, it is determined whether both plus side and minus side data exist for the same phase control current Iph,
If there is, (minus side DBR drive current Idb
r)-(plus side DBR drive current Idbr) is obtained, and the process proceeds to the next process. If there is no such process, the process proceeds to the next process (S4).
3, S44).

Then, the plus side data stored by the current ratio calculating means 82 is set as the phase control current Iph of the next data (S45). It is determined again whether all the plus side data stored have been checked (S42).

When all the positive side data are examined, the average of the peak width of the blue light output power is obtained (S4).
6). Then, the straight line on the side with more data obtained by the current ratio calculating means 82 is moved with respect to the DBR drive current by の of the average of the width to obtain a straight line passing near the center of the mountain (S4).
7). The DBR driving current Idbr and the phase control current Iph are changed along this straight line and applied to the DBR semiconductor laser 1, and based on the electric signal from the photodetector 3, the DBR driving current Idbr at which the blue light output power is maximized. , And the combination of the phase control current Iph as the pole current (S48).

That is, the width of the DBR drive current Idbr at the change point of blue light is determined, and the average value of the width is determined. Then, as shown in FIG. 10, for example, a straight line b is moved by a half of this average value to obtain a straight line a. Along this straight line a, the DBR drive current Idbr and the phase control current Ip
By changing h, the pole current at which the blue light output power is maximized is determined.

As described above, the provisional control parameter calculating means 8
In step 1, the temporary control parameters (DBR drive current Idbr, phase control current Iph) are determined, and the current ratio calculation means 82 determines the current ratio from the change in the blue light output power with the temporary control parameter as the center. , The control parameter determining means 83 obtains the pole current. Thereby, the control parameters (DBR drive current Idbr, phase control current Ip
h) can be obtained.

If the DBR driving current and the phase control current of the DBR semiconductor laser 1 are controlled by the current ratio calculated by the current ratio calculating means 82, the blue light output power changes as shown in FIG. That is, it is possible to easily obtain a control parameter with which the blue light output power varies.

When the SHG laser light source (DBR semiconductor laser 1 and SHG element 2) has to be replaced due to a failure or the like, the control parameters of the SHG laser light source can be easily obtained. SH
The G laser light source can be replaced.

Note that the present invention is not limited to this, and a configuration without provisional control parameter calculating means 81 may be used. In other words, if the control parameter at which the approximate output power is maximized is known in advance, the current ratio calculating means 8
A configuration for obtaining the control parameter from 2 may be used.

Although the configuration in which the current ratio calculation means 82 is provided is shown, the control parameter determination means 83 does not calculate the current ratio if the DBR drive current and the phase control current can be changed at the center of the change point. May be.

[0067]

According to the present invention, the following effects can be obtained. According to the first and fourth aspects, the DBR drive current and the phase control current are changed, and the pole current is obtained from the change point of the second harmonic light output power. As a result, it is possible to easily obtain control parameters (DBR drive current and phase control current) in which the second harmonic light output power is stable at a high output power.

According to the second and fifth aspects, the DBR drive current,
By changing the phase control current, a current ratio is determined from a change in the second harmonic optical output power, and a pole current is determined from the current ratio. This makes it possible to easily obtain control parameters (DBR drive current Idbr, phase control current Iph) at which the second harmonic light output power is high and stable.

If the DBR driving current and the phase control current of the semiconductor laser are controlled by the current ratio, the second harmonic light output power changes. That is, it is possible to easily obtain a control parameter that allows the second harmonic light output power to vary.

According to the third and sixth aspects, the DBR drive current and the phase control current are changed to determine the provisional control parameter that is the maximum power of the second harmonic light. Even if is not specified, it is possible to specify the region of the control parameter that is stable and has high output power.

[Brief description of the drawings]

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

FIG. 2 shows a DBR drive current Idbr and a phase control current Ip
h is a diagram showing a relationship with blue light output power.

FIG. 3 is an enlarged view of a specific range in FIG. 2;

FIG. 4 is a diagram showing the relationship between blue light output power and DBR drive current.

FIG. 5 is a flowchart showing a schematic operation of the apparatus shown in FIG. 1;

FIG. 6 is a flowchart showing an operation of step 1 of the flowchart shown in FIG. 5;

FIG. 7 is a flowchart showing an operation of step 2 of the flowchart shown in FIG. 5;

FIG. 8 is a flowchart showing the operation of step 3 of the flowchart shown in FIG. 5;

FIG. 9 is a flowchart showing an operation of step 4 of the flowchart shown in FIG. 5;

FIG. 10 is a diagram illustrating the operation of the device shown in FIG.

FIG. 11 is a diagram showing a configuration of a conventional SHG laser light source.

FIG. 12 is a diagram showing characteristics of the SHG element 2.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 DBR semiconductor laser 2 SHG element 3 Photodetector 8 Control part 11 Active part 12 Phase part 13 DBR part 81 Temporary control parameter calculation means 82 Current ratio calculation means 83 Control parameter determination means

Claims (6)

[Claims] 1. A semiconductor laser having an active part, a phase part, and a DBR part having a distributed Bragg reflector (DBR) formed thereon, and a wavelength conversion of light of the semiconductor laser is performed.
A control parameter calculating device for obtaining a control parameter of a high output power of the second harmonic light in the SHG laser light source including the SHG element that outputs the harmonic light, wherein the second harmonic light output by the SHG element is input; A photodetector that converts the signal into an electric signal; a DBR drive current supplied to the DBR unit; and a phase control current supplied to the phase unit. The output signal of the second harmonic light is changed by the electric signal from the photodetector. The DBR drive current and the phase control current are changed at the center of the change point on the minus side and the plus side, and the DBR of the high output power of the second harmonic light is obtained by the electric signal from the photodetector.
A control parameter calculation device for an SHG laser light source, comprising: control parameter determination means for obtaining a drive current and a phase control current. 2. A semiconductor laser having an active part, a phase part, and a DBR part on which a distributed Bragg reflector (DBR) is formed.
A control parameter calculating device for obtaining a control parameter of a high output power of the second harmonic light in the SHG laser light source including the SHG element that outputs the harmonic light, wherein the second harmonic light output by the SHG element is input; A photodetector that converts the electric power into an electric signal; a DBR drive current supplied to the DBR unit; and a phase control current supplied to the phase unit, the output power of the second harmonic light being changed by the electric signal from the photodetector. Of the DBR drive current and the phase control current of
Current ratio calculating means for calculating a current ratio between the R drive current and the phase control current; and changing the DBR drive current and the phase control current at the centers of the minus and plus change points by the current ratio of the current ratio calculation means. And a control parameter determining means for obtaining a DBR drive current and a phase control current of a high output power of the second harmonic light based on an electric signal from the photodetector. 3. A DBR driving current and a phase control current are changed at desired intervals, and a second signal is outputted by an electric signal from a photodetector.
Provisional control parameter calculation means for obtaining a DBR drive current and a phase control current of a provisional maximum value of the output power of the harmonic light;
Based on the provisional maximum value of the DBR drive current and the phase control current,
3. The control parameter calculating device for an SHG laser light source according to claim 1, wherein a change point of the output power of the second harmonic light is obtained. 4. A semiconductor laser having an active part, a phase part, and a DBR part on which a distributed Bragg reflector (DBR) is formed, and a wavelength conversion of light of the semiconductor laser is performed.
A control parameter calculating method for obtaining a control parameter of a high output power of a second harmonic light in an SHG laser light source including an SHG element for outputting a harmonic light, wherein a DBR driving current to be provided to the DBR unit and a control parameter to be provided to the phase unit By changing the phase control current, a change point of the output power of the second harmonic light is obtained, and the phase control current and the DBR drive current are changed at the center of the change points on the minus side and the plus side to obtain the second point.
A control parameter calculation method for an SHG laser light source, wherein a DBR drive current and a phase control current of high output power of harmonic light are obtained. 5. A semiconductor laser having an active part, a phase part, and a DBR part on which a distributed Bragg reflector (DBR) is formed, and performing wavelength conversion of light of the semiconductor laser to form a second semiconductor laser.
A control parameter calculating method for obtaining a control parameter of a high output power of a second harmonic light in an SHG laser light source including an SHG element for outputting a harmonic light, wherein a DBR driving current to be provided to the DBR unit and a control parameter to be provided to the phase unit By changing the phase control current, a DBR drive current and a phase control current at a change point of the output power of the second harmonic light are obtained, and a current ratio between the DBR drive current and the phase control current is obtained from the change point. A phase control current and a DBR drive current at the center of a change point on the minus side and a plus side to obtain a DBR drive current and a phase control current having a high output power of the second harmonic light. Control parameter calculation method. 6. The DBR drive current and the phase control current are changed at desired intervals, and a DBR drive current and a phase control current of a temporary maximum value of the output power of the second harmonic light are obtained. Based on the phase control current,
6. The method according to claim 4, wherein a change point of the output power of the second harmonic light is obtained.