JP3018717B2 - Short wavelength laser light source and method of manufacturing short wavelength laser light source - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser light source used for optical recording / reproduction, optical measurement, and the like.

[0002]

2. Description of the Related Art A conventional short wavelength laser light source is disclosed in, for example, Kuroda and Kubota: Optics, 19, 136 and 1990.

FIG. 4 shows the configuration of a conventional short-wavelength laser light source, wherein 1 is a semiconductor laser chip for generating laser light having a wavelength of 0.809 μm, 2 is a semiconductor laser mount, and 3 is a semiconductor laser chip. solid Le is - the medium as for example Nd: YVO _4, and transmittance of 99.5% for a wavelength 0.809μm is the plane indicated by 4, the wavelength 1.064μm and the wavelength 0.53
A coating having a reflectivity of 99.9% is applied to 2 μm. 5 is a wavelength conversion element such as KTP, 6
Is a reflecting mirror, and the wavelength 0.532
A coating having a transmittance of 99.9% for .mu.m and a reflectance of 99.9% for a wavelength of 1.064 .mu.m is provided. Reference numeral 8 denotes a filter that selectively transmits a wavelength of 0.532 μm. The optical axis of the semiconductor laser mount 2, the solid-state laser medium 3, the wavelength conversion element 5, and the reflecting mirror 6 is adjusted to an optimal position, and the semiconductor laser mount 2 is fixed to the module housing 26 using screws or an adhesive.

FIG. 5 shows an optical axis adjusting method in the manufacturing process of the conventional short wavelength laser light source shown in FIG. 2
Is a semiconductor laser mount, 26 is a module housing, 27
Indicates a column supporting the module housing 26. Reference numeral 22 denotes a drive power source for the short wavelength laser light source, and reference numeral 23 denotes a wavelength of 0.532 μm.
, An optical detector 24, and an optical power meter 25. Reference numeral 28 denotes a temperature control unit incorporating a Peltier element, and 29 denotes a temperature control circuit.

A method for adjusting the optical axis of the short-wavelength laser light source having the above-described configuration will be described. The semiconductor laser 1 shown in FIG. 4 excites the solid-state laser medium 3 also shown in FIG. 4, but in order to maximize the excitation efficiency, the semiconductor laser 1
Is the absorption peak of the solid laser medium 3 (eg, Nd:
It is necessary to match the case 0.809Myuemu) of YVO _4. For this reason, the temperature of the semiconductor laser mount 2 is adjusted by the temperature control unit 28 and the temperature control circuit 29 so that the wavelength is maintained at 0.809 μm.
Next, a predetermined current is applied to the semiconductor laser by the drive power supply 22 so that the output 23 is generated and the monitor value of the optical power meter 25 is maximized. The positions of the solid laser medium 3, the wavelength conversion element 5, and the reflecting mirror 6 as shown are adjusted and fixed.

[0006]

However, according to the study of the present inventors, in the short-wavelength laser light source having the above-described structure, the semiconductor laser mount 2, that is, the semiconductor laser 1, is driven for the above-described reason during driving. The temperature must always be controlled to a predetermined value. On the other hand, the KTP used for the wavelength conversion element 5 has a temperature dependence in its wavelength conversion efficiency. Must be tuned to an optimum value, and therefore, the temperature of the semiconductor laser 1 and the temperature of the module housing 26 must be set to different values.
Has been found to be very difficult to join.
In the adjustment of the optical axis of the solid-state laser medium 3, the wavelength conversion element 5, and the reflecting mirror 6 and the fixing to the module housing 26, a clearance corresponding to each adjustment margin is secured, and then the thermal strain is applied. It has been a very difficult task in mechanical design to fix the optical axis without causing optical axis deviation.
SUMMARY OF THE INVENTION An object of the present invention is to provide a short wavelength laser light source capable of obtaining maximum oscillation efficiency and having excellent reliability, and a method of manufacturing the same.

[0007]

SUMMARY OF THE INVENTION The present invention provides a solid-state laser medium.
And a semiconductor laser for exciting the solid-state laser medium.
And resonate light excited by the solid-state laser medium.
A pair of mirrors facing each other and the wavelength of the excited light
An optical wavelength conversion element for halving and using the same optical axis
Short wavelength laser light source with a housing fixed on top
The solid-state laser medium, the optical wavelength conversion element,
A pair of mirrors in holders with projections around each
And the casing has at least one of the outer circumferences parallel to the optical axis.
Is provided on the inner wall surface facing the optical axis.
The solid-state laser medium, the light wavelength conversion element, and the opposing one
At a position corresponding to the mounting position of the pair of mirrors, perpendicular to the optical axis
A groove that is larger than the cross-sectional area of the holder protrusion.
Will be successful. The present invention also relates to the above-mentioned short wavelength laser light source.
The solid-state laser medium, the optical wavelength conversion element, and the
Insert the projecting part of the holder that stores the mirror pair into the groove on the inner wall of the housing.
Into the solid-state laser medium, light wavelength conversion element and
A pair of mirrors facing each other are illuminated
After adjusting the axis, a fixing agent is injected into the groove and the holder is
The optical axis adjustment position is maintained by fixing the projection.
It is a manufacturing method of holding.

[0008]

According to the present invention, the above means improves the bonding reliability between the semiconductor laser and the housing and improves the heat conductivity by forming the two into an integrated structure. A structure suitable for controlling at the same temperature is obtained. On the other hand, when manufacturing the present short wavelength laser light source, by controlling the temperature of the heat sink on which the housing is mounted to a temperature set value at the time of driving, the solid-state laser medium, the optical wavelength conversion element, and the The temperature of the mirror is also the same as the above temperature, and the solid laser medium, the optical wavelength conversion element and the protrusions of the holders containing the pair of mirrors facing each other are fixed to the grooves provided in the housing after the respective position adjustments. In addition, it is possible to assemble such that the maximum oscillation efficiency is obtained at the set temperature. It is known that the optimization of the conversion efficiency by adjusting the temperature of the optical wavelength conversion element can be replaced by the position adjustment (particularly, the angle adjustment) of the optical wavelength conversion element. By performing the configuration and the manufacturing process as described above, when controlling the temperature of the entire housing at the time of driving,
Short-wavelength laser oscillation can be achieved under the optimal setting conditions simultaneously in both the wavelength of the semiconductor laser and the conversion efficiency of the optical wavelength conversion element, and an extremely small laser module can be realized.

[0009]

FIG. 1 shows the configuration of a short-wavelength laser light source according to a reference example , wherein 1 is a semiconductor laser chip for generating laser light having a wavelength of 0.809 .mu.m, and 2 is a diameter B. The semiconductor laser mount 3 is, for example, Nd: YVO ₄ as a solid laser medium, and the surface indicated by 4 has a transmittance of 99.5% for a wavelength of 0.809 μm and a wavelength of 1.0.
A reflectivity of 9 for 64 μm and a wavelength of 0.532 μm.
It has a 9.9% coating. Reference numeral 5 denotes a wavelength conversion element, for example, KTP, and reference numeral 6 denotes a reflecting mirror. The transmittance of the concave portion shown by 7 is 99.99 for a wavelength of 0.532 μm.
9% and a coating having a reflectivity of 99.9% for a wavelength of 1.064 μm. 8 is 0.532 μm in wavelength
This is a filter that selectively allows only light to pass. Reference numeral 9 denotes a module housing for fixing the semiconductor laser mount 2, the solid-state laser medium 3, the wavelength conversion element 5, the reflecting mirror 6, and the filter 8 on the optical axis. It has an opening having A = B−0.03 mm, and is formed of a metal having substantially the same thermal expansion coefficient as the semiconductor laser mount 2.

A method of assembling the short-wavelength laser light source having the above-described configuration will be described. First, the semiconductor laser mount 2
Into the opening of the module housing 9. On this occasion,
As described above, since the hole size A is smaller than the outer size B of the semiconductor laser mount 2, a certain pressure is required for fitting. Next, after adjusting the solid laser medium 4, the wavelength conversion element 5, and the reflecting mirror 6 to the optimum positions, the solid laser medium 4, the wavelength converting element 5, and the reflecting mirror 6 are fixed to the module housing 9 by using an adhesive or by a method such as screwing. By adopting such a method, the bonding between the semiconductor laser mount 2 and the module housing 9 can be performed with high reliability against an external load such as a change in environmental temperature and an external vibration such as vibration, and can be performed with excellent heat conductivity. This is advantageous when performing batch temperature control of the entire module including the semiconductor laser.

[0011] Figure 2 shows the structure of the short wavelength laser light source according to an embodiment of the present invention according to claim 1, 1 designates a semiconductor laser chip for generating laser light of wavelength 0.809Myuemu, 2 denotes a semiconductor laser mount , 3 for example, as a solid-state laser medium Nd: YVO _4, and transmittance of 99.5% for a wavelength 0.809μm is the plane indicated by 4, the wavelength 1.
A coating having a reflectivity of 99.9% is applied to 064 μm and a wavelength of 0.532 μm. Reference numeral 5 denotes a wavelength conversion element, for example, KTP, and reference numeral 6 denotes a reflecting mirror having a wavelength of 0.1.
For 532 μm, the transmittance is 99.9% and the wavelength is 1.064.
A coating having a reflectivity of 99.9% is applied to μm. Reference numeral 8 denotes a filter that selectively transmits only the wavelength of 0.532 μm. Reference numeral 10 denotes a module housing for fixing the semiconductor laser mount 2, the solid-state laser medium 3, the wavelength conversion element 5, the reflecting mirror 6, and the filter 8 on the optical axis, and a groove 11 is provided at a mounting position of each of these components. And at least one in a plane parallel to the optical axis.
It has two openings. Also, this module housing 1
Numeral 0 is formed of a metal having substantially the same thermal expansion coefficient as the semiconductor laser mount 2. Reference numerals 12, 13, and 14 denote holders for accommodating the solid-state laser medium 3, the wavelength conversion element 5, and the reflecting mirror 6, respectively. The individual parts are fixed with an adhesive 15 having excellent heat conductivity. 16 is the holder 12, 1
Projections 16 provided on 3 and 14. Reference numeral 17 denotes a fixing agent for fixing the holders 12, 13, and 14 to the module housing 10. For example, a molten metal such as solder or a silicon-based adhesive having excellent heat conductivity is used.

An assembling method according to the second aspect of the present invention will be described for the short-wavelength laser light source configured as described above. First, the semiconductor laser mount 2 is attached to the module housing 1.
Fix to 0. The method at this time may be any method that does not cause a positional shift due to a change in environmental conditions or the like, and may be press-fitted as in claim 1 of the present invention or fixed with an adhesive or a screw. Next, the solid-state laser medium 3, the wavelength conversion element 5, and the reflecting mirror 6 are placed in holders 12, 13, and 14, respectively.
Then, the adhesive 15 is applied and fixed so as to fill those gaps. At this time, heat or the like may be applied to enhance the adhesiveness of the adhesive 15. A method of fixing the solid-state laser medium 3, the wavelength conversion element 5, and the reflecting mirror 6 fixed to the holder as described above to the module housing 10 will be described.
First, the solid-state laser medium 3 fixed to the holder 12 is
From the opening plane parallel to the optical axis in the module housing 10,
It is inserted from a direction perpendicular to the optical axis, and is held from outside using a jig or the like so that the solid-state laser medium 3 is positioned near the optical axis. At this time, the projection 16 of the holder 12 is set in the groove 11 provided in the module housing 10.
After performing the same operation for the wavelength conversion element 5 and the reflecting mirror 6, the positions of the holders 12, 13, and 14 are adjusted under a constant temperature so that the laser oscillation condition of the wavelength of 0.532 μm is optimized. While holding these with the holder, the groove 1
A fixing agent 17 is poured into 1 and fixed. The fixing agent 1
If it takes time for the resin 7 to harden, it may be temporarily fixed using an instant adhesive or the like, and the fixing agent 17 may be used as the next step. Finally, the filter 8 is attached to the module housing 10. By adopting such a method, the solid-state laser medium 3, the wavelength conversion element 5, and the reflecting mirror 6 are fixed to the module housing 10 via the projections 16 on the holders 12, 13, and 14. That is, the contact area at the joint can be significantly reduced as compared with the related art. For this reason, it is hard to be affected by the thermal strain due to the fluctuation of the ambient temperature and the like, and the reliability is improved. In addition, since the position adjustment allowance is large, the optimum adjustment can be easily performed, and since the adjustment mechanism (jig) is provided outside the module housing 10 as described above, the structure of the module becomes extremely simple. , Miniaturization becomes possible.

FIG. 3 shows an optical axis adjusting method in a manufacturing process of a short wavelength laser light source in a reference example . Reference numeral 18 denotes a module housing, and 19 denotes a heat sink made of a copper or brass block, which contacts the module housing 18 during assembly of the short-wavelength laser light source. Reference numeral 20 denotes a temperature control unit incorporating a Peltier element, and reference numeral 21 denotes a temperature control circuit. Reference numeral 22 denotes a drive power supply for the short wavelength laser light source, 23 denotes an output laser beam having a wavelength of 0.532 μm, 24 denotes an optical detector, and 25 denotes an optical power meter.

A method of adjusting the optical axis of the short-wavelength laser light source having the above-described configuration will be described. The semiconductor laser 1 shown in FIG. 3 previously fixed to the module housing 18.
Must be matched to the absorption peak (for example, 0.809 μm in the case of Nd: YVO ₄ ) of the solid laser medium 3 which is also a component of the short wavelength laser light source. Therefore, the temperature of the heat sink 19 on which the module housing 18 is mounted is adjusted by the temperature control unit 20 and the temperature control circuit 21 so that the wavelength of the semiconductor laser becomes 0.809 μm. Next, a predetermined current is applied to the semiconductor laser by the driving power supply 22, and the semiconductor laser is positioned inside the module housing 18 so that the output 23 is generated and the monitor value of the optical power meter 25 is maximized.
The positions of the solid-state laser medium 3, the wavelength conversion element 5, and the reflecting mirror 6 are adjusted and fixed. At this time, since the temperature of the module case 18 is maintained at the set temperature, the solid-state laser medium 3, the wavelength conversion element 5
The optical axis is adjusted with the temperature of the reflecting mirror 6 also at the same temperature.

By employing such a method, the same temperature control as that performed on the module housing 18 to keep the wavelength of the semiconductor laser at 0.809 μm when driving the short wavelength laser light source is performed. Since the optical axis adjustment is performed at the set temperature, the state difference between the optical axis adjustment and the driving time, which has conventionally occurred, is eliminated, and extremely stable laser oscillation can be realized. In particular, since the conversion characteristics of the wavelength conversion element have a remarkable temperature dependency, it is effective to keep the temperature constant during use, and the setting by adopting the assembling method described above. Since the optimum position adjustment is performed at the temperature, the optimum state is always reproduced during the operation.

[0016]

As described above, according to the configuration and the manufacturing method of the present invention, the positions of the components are adjusted so that the short-wavelength laser light source is in an optimum state during operation, and the maximum oscillation efficiency is maximized. As well as being obtained, the output becomes extremely stable, and its practical effect will be greatly improved,
This greatly contributes to the practical use of short wavelength laser light sources.

[Brief description of the drawings]

FIG. 1 is a sectional view of a principal part of a short wavelength laser light source according to a reference example .

FIG. 2 is a sectional view of a main part of a short wavelength laser light source according to an embodiment of the present invention;

FIG. 3 is a configuration diagram showing a method of manufacturing a short wavelength laser light source according to a reference example .

FIG. 4 is a sectional view of a main part of a conventional short wavelength laser light source.

FIG. 5 is a configuration diagram showing a conventional method for manufacturing a short-wavelength laser light source.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor laser chip 2 Semiconductor laser mount 3 Solid-state laser medium 4 Coating 5 Wavelength conversion element 6 Reflector 7 Coating 8 Filter 9 Module housing 10 Module housing 11 Groove 12 Holder 13 Holder 14 Holder 15 Adhesive 16 Projection 17 Fixing agent 19 Heat sink 20 Temperature adjustment unit 21 Temperature controller 22 Drive power supply 24 Optical detector 25 Optical power meter

Continuation of the front page (56) References JP-A-5-173215 (JP, A) JP-A-5-235441 (JP, A) JP-A-5-198876 (JP, A) JP-A-5-198870 (JP) JP-A-2-122258 (JP, A) JP-A-3-88380 (JP, A) JP-A-3-145778 (JP, A) JP-A-4-25083 (JP, A) 4-94768 (JP, U) JP-A 4-85315 (JP, U) JP-A 4-97375 (JP, U) Table 3-505948 (JP, A) (58) Fields surveyed (Int. Cl. ⁷ , DB name) H01S 3/108-3/109 G02F 1/37 H01S 3/094

Claims (2)

(57) [Claims] A solid-state laser medium, a semiconductor laser for exciting the solid-state laser medium, and a pair of opposed mirrors for resonating light excited by the solid-state laser medium;
An optical wavelength conversion element for halving the wavelength of the excited light, and a short-wavelength laser light source including a housing for fixing them on the same optical axis, wherein the solid-state laser medium, the optical wavelength conversion element, A pair of mirrors facing each other are housed in holders each having a projection on the periphery, the housing is provided with one or more openings in the outer periphery parallel to the optical axis, and the inner wall surface facing the optical axis has A short-wavelength laser in which a groove larger than a cross-sectional area of the holder protrusion is provided in a position corresponding to a mounting position of the solid-state laser medium, the light wavelength conversion element, and a pair of mirrors facing each other in a direction perpendicular to an optical axis. light source. 2. A short-wavelength laser light source according to claim 1 , wherein said solid-state laser medium, an optical wavelength conversion element, and a projecting portion of a holder for accommodating a pair of mirrors facing each other are inserted into grooves on an inner wall of said housing. After adjusting the optical axis of the laser medium, the light wavelength conversion element, and the pair of mirrors facing each other to an arbitrary position at a constant temperature, a fixing agent is injected into the groove to fix the protrusion of the holder, thereby obtaining the light. A method for manufacturing a short-wavelength laser light source, wherein an axis adjustment position is maintained.