JP2006293110A - Laser device manufacturing method and laser device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a laser device for improving stability of a polarization direction of laser light propagating through an optical fiber, and to provide a laser device. <P>SOLUTION: The method for manufacturing a light source device 1 of visible light comprises at least three steps that: an optical fiber 4 is optically coupled with a semiconductor laser 3 in a first step; at least a part of the optical fiber 4 is bent in a second step; and the bent portion of the optical fiber 4 is annealed in an atmosphere at a specified temperature or higher in a third step. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a laser device manufacturing method and a laser device.

  Conventionally, a laser apparatus having a structure in which a laser light source and an optical fiber are joined has been developed.

For example, as shown in the following Patent Document 1, in order to propagate laser light emitted from a laser light source to an optical fiber with high efficiency without leakage, an optical axis adjustment that performs relative positioning between the laser light source and the optical fiber is performed. Techniques for wicks have been devised. Specifically, each of the joining portions of the laser light source and the optical fiber is covered with a ferrule, and the ferrule is fixed to bond the laser light source and the optical fiber. Then, the optical axis is aligned by changing the relative position between the laser light source and the optical fiber by irradiating the ferrule of the joint portion with laser light to perform laser forming.
JP 2004-29351 A (published January 29, 2004)

  However, the conventional laser apparatus focuses only on the change in the relative position of the joint between the laser light source and the optical fiber, and does not consider any change in the polarization direction of the laser light propagated by the optical fiber. Absent.

  For example, there is a case where a part of an optical fiber is bent and fixed and stored in a predetermined region in response to a request for downsizing a laser device. When the optical fiber is fixed with a curved portion in this way, stress strain occurs in the curved portion, and this stress strain may remain as residual stress in the curved portion. Further, the residual stress of this optical fiber changes under the influence of ambient temperature change and atmospheric pressure change. Such a change in the distribution of residual stress in the optical fiber may cause a change in the polarization direction of the propagated laser beam, which may make it difficult to propagate the laser beam while stabilizing the polarization direction. There is.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a laser device manufacturing method and a laser device capable of improving the stability of the polarization direction of laser light propagated by an optical fiber. Is to provide.

  The method for manufacturing a laser device according to the first invention comprises at least the following three steps. In the first step, the optical fiber is optically coupled to the laser light source. In the second step, at least a part of the optical fiber is bent. In the third step, annealing is performed by placing the curved portion of the optical fiber in an atmosphere having a predetermined temperature or higher. The object to be annealed is not particularly limited to the curved part, and may be the curved part and its vicinity. Further, since the laser light source and the optical fiber need only be optically coupled, the laser light source and the optical fiber may be physically separated.

  In the conventional laser device, when the influence of ambient temperature changes, the polarization direction of the laser beam changes due to the distribution of the residual stress distribution in the optical fiber, and the laser beam remains stable while the polarization direction remains stable. Is difficult to propagate.

  In contrast, in the method for manufacturing a laser device according to the first aspect of the invention, annealing is performed by placing a curved portion of an optical fiber optically coupled to a laser light source in an atmosphere at a predetermined temperature or higher. For this reason, even if there is a curved portion in the optical fiber optically coupled to the laser light source, and residual stress may exist in this curved portion, the residual is obtained by annealing the curved portion. Disperse the stress. The annealing conditions here may be determined based on the melting point of the curved portion of the optical fiber.

  Thereby, even if ambient temperature and atmospheric pressure change, the change in the distribution of residual stress in the curved portion of the optical fiber can be suppressed. Therefore, it is possible to manufacture a laser device that can stabilize the polarization direction of the laser light propagated by the optical fiber even when the ambient temperature or pressure changes.

  In addition, for example, by providing a curved portion in the optical fiber installation process, the refractive index of the curved portion of the optical fiber may change under the influence of changes in ambient temperature and pressure. However, even when the ambient temperature and pressure change due to the above-described annealing, the change in the refractive index in the curved portion of the optical fiber can be suppressed. Therefore, it is possible to manufacture a laser device that can stabilize the polarization direction of the laser light propagated by the optical fiber even when the ambient temperature or pressure changes.

  Note that the above-described annealing may be performed not only on the curved portion but also on the curved portion and its vicinity, for example. Thereby, even when the residual stress is present not only in the curved portion but also in the vicinity thereof, the polarization direction of the laser light propagated by the optical fiber can be more reliably stabilized.

  In addition, even if the optical fiber is bent, it becomes possible to stabilize the polarization direction of the laser beam propagated by annealing. For example, a component optically coupled to the optical fiber (for example, wavelength conversion) It is possible to improve the degree of freedom of arrangement of crystals and the like. As the degree of freedom of component placement increases, the laser device can be reduced in size.

  The method for manufacturing a laser device according to the second invention comprises at least the following three steps. In the first step, the optical fiber is optically coupled to the laser light source. In the second step, at least a part of the optical fiber is fixed via a fixing member. In the third step, annealing is performed by placing a portion near the fixing member of the optical fiber and the fixing member in an atmosphere at a predetermined temperature or higher. Since the laser light source and the optical fiber may be optically coupled, the laser light source and the optical fiber may be physically separated from each other. The optical fiber fixing target here includes, for example, an optical mount as a base on which a laser light source is attached, but is not particularly limited thereto. The fixing member includes a case where the fixing member is used for fixing optical fibers.

  In the conventional laser apparatus, when the influence of the surrounding temperature changes, the fixing member expands and contracts to change the distribution of the residual stress of the optical fiber, thereby changing the polarization direction of the laser light. It is difficult to propagate the laser light while keeping the polarization direction stable.

  In contrast, in the method of manufacturing the laser device according to the second aspect of the invention, annealing is performed by placing the vicinity of the fixing member of the optical fiber optically coupled to the laser light source and the fixing member in an atmosphere at a predetermined temperature or higher. Do.

  For this reason, even if there is a fixed part in the optical fiber optically coupled to the laser light source, and residual stress may exist in this fixed part, it remains by performing annealing on this fixed part. Disperse the stress. In addition, annealing is also performed on the fixing member that fixes the fixing portion, so that residual stress is prevented from being generated in the optical fiber in the vicinity of the fixing member due to expansion and contraction of the fixing member. Here, the annealing conditions for the fixing member may be determined based on the melting point of the fixing member.

  Thereby, even if the ambient temperature and pressure change, the change in the distribution of residual stress in the vicinity of the fixing member of the optical fiber can be suppressed. Therefore, it is possible to manufacture a laser device that can stabilize the polarization direction of the laser light propagated by the optical fiber even when the ambient temperature or pressure changes.

  Further, for example, when the fixing member is used in the optical fiber installation process, the refractive index in the vicinity of the fixing member of the optical fiber may change due to the influence of ambient temperature and atmospheric pressure. However, even if the ambient temperature and pressure change due to the above-described annealing, the change in the refractive index in the vicinity of the fixing member of the optical fiber can be suppressed. Therefore, it is possible to manufacture a laser device that can stabilize the polarization direction of the laser light propagated by the optical fiber even when the ambient temperature or pressure changes.

  A laser device manufacturing method according to a third invention is the laser device manufacturing method according to the first or second invention, wherein the optical fiber has a length exceeding the coherent length.

  When the optical fiber is short, reflected light is generated from the end of the optical fiber and may interfere with the laser light from the laser light source.

  On the other hand, in the laser device manufacturing method of the third invention, a length exceeding the coherent length is ensured. For this reason, the reflected light from the end portion of the optical fiber is propagated via a length exceeding the coherent length, and becomes a light whose wavelength and phase are disturbed. Thereby, the influence which the laser beam from a laser light source receives by the reflected light from the edge part of an optical fiber is suppressed.

  Therefore, it is possible to obtain harmonic light having a stable output.

  Also, for example, when an optical fiber having a length exceeding the coherent length is provided and the installation space in the laser device is limited, a part of the optical fiber is bent and stored in a predetermined region. May need to be done. However, even when an optical fiber having a length exceeding the coherent length is bent and accommodated as described above, the residual stress in the bent portion is dispersed by annealing, and the laser light propagates while stabilizing the polarization direction. It becomes possible.

  A method for manufacturing a laser device according to a fourth aspect of the present invention is the method for manufacturing a laser device according to any one of the first to third aspects, wherein the predetermined temperature for annealing is warmed when the laser beam is propagated. The temperature is higher than the operating temperature when using an optical fiber. The operating temperature is the temperature at which the optical fiber heated when propagating the laser light emitted from the laser light source is used. Note that the operating temperature may be, for example, about 45 ° C. as the temperature of the optical fiber during use.

  Here, the optical fiber is annealed at a temperature higher than the operating temperature. As a result, residual stress that cannot be dispersed simply by using an optical fiber is also dispersed.

  Therefore, the residual stress of the optical fiber can be effectively dispersed.

  A method for manufacturing a laser device according to a fifth aspect of the present invention is the method for manufacturing a laser device according to the fourth aspect, wherein the predetermined temperature when annealing is equal to or higher than the use temperature and equal to or higher than the upper limit temperature of the optical fiber storage temperature range. Temperature. Note that the storage temperature range is a temperature range in which the propagation function of the optical fiber is maintained such that the polarization direction of the laser light propagates while being stabilized.

  Here, the residual stress of the optical fiber is effectively dispersed by annealing at a temperature in the storage temperature range that is higher than the use temperature. Moreover, since it is within the storage temperature range, loss of the propagation function of the optical fiber can be prevented.

  Therefore, it is possible to prevent the loss of the propagation function of the optical fiber while more efficiently dispersing the residual stress of the optical fiber.

  In addition, when the storage temperature range of an optical fiber is about 60-80 degreeC, for example, it is preferable to anneal by lower temperature (for example, 60 degreeC) within the storage temperature range. Thereby, damage to other elements of the laser device can be reduced.

  A method for manufacturing a laser device according to a sixth aspect of the present invention is the method for manufacturing a laser device according to any one of the first to fifth aspects, wherein annealing is performed for 1 hour or more.

  Here, the inside of the optical fiber is heated by annealing for 1 hour or longer. For this reason, not only the residual stress in the vicinity of the surface of the optical fiber but also the residual stress in the optical fiber is dispersed.

  Therefore, the residual stress of the optical fiber can be more reliably dispersed.

  A laser apparatus according to a seventh aspect of the invention is a laser apparatus manufactured by the method for manufacturing a laser apparatus according to any one of the first to sixth aspects of the invention.

  Here, even when the ambient temperature or pressure changes, the polarization direction of the laser light propagated by the optical fiber can be stabilized.

  In the laser device manufacturing method according to the first aspect of the present invention, it is possible to suppress a change in the distribution of residual stress in the curved portion even when the ambient temperature or pressure changes, and the laser propagated by the optical fiber A laser device capable of stabilizing the polarization direction of light can be manufactured.

  In the laser device manufacturing method according to the second aspect of the present invention, it is possible to suppress the change in the residual stress distribution in the vicinity of the fixing member of the optical fiber even when the ambient air temperature or atmospheric pressure changes. Thus, it is possible to manufacture a laser device that can stabilize the polarization direction of the laser light propagated by the laser beam.

  In the method for manufacturing a laser device according to the third aspect of the invention, it is possible to obtain harmonic light with a stable output.

  In the laser device manufacturing method according to the fourth aspect of the present invention, it is possible to effectively disperse the residual stress of the optical fiber.

  In the laser device manufacturing method according to the fifth aspect of the present invention, it is possible to prevent the loss of the propagation function of the optical fiber while more efficiently dispersing the residual stress of the optical fiber.

  In the method for manufacturing a laser device according to the sixth aspect of the present invention, the residual stress of the optical fiber can be more reliably dispersed.

  In the laser device according to the seventh aspect of the present invention, it is possible to stabilize the polarization direction of the laser light propagated by the optical fiber even when the ambient temperature or pressure changes.

<Outline of visible light source device 1>
The manufacturing method of the visible light source device 1 according to an embodiment of the present invention is a manufacturing method of the visible light source device 1 from which a visible light laser with stable output can be obtained.

  In FIG. 1, the structure in the periphery of the optical mount 2 with which the visible light source device 1 is provided is shown.

  The visible light source device 1 is configured by providing a semiconductor laser 3, an optical fiber 4, and a wavelength conversion element 5 with respect to the optical mount 2, and is arranged as shown in FIG. 1.

  The semiconductor laser 3 is a semiconductor laser that oscillates near infrared rays. For example, those that oscillate near-infrared laser light having a wavelength of 940 nm (the fundamental wave of visible blue light), those that oscillate near-infrared laser light having a wavelength of 1060 nm (the fundamental wave of visible green light), etc. Used.

  As shown in FIG. 1, one end of the optical fiber 4 is optically coupled to the semiconductor laser 3 and propagates laser light emitted from the semiconductor laser 3. The optical fiber 4 is provided to efficiently guide laser light emitted from the semiconductor laser 3 to a waveguide 6 (described later) in the wavelength conversion element 5.

  The optical fiber 4 has a length exceeding the coherent length, and is provided so as to be bent on the optical mount 2 and fixed by an adhesive 7 as shown in FIG. The adhesive 7 not only bonds the optical fiber 4 and the optical mount 2 but also bonds the optical fibers 4 to each other. Here, the optical fiber 4 having a length exceeding the coherent length is provided, thereby suppressing the influence of interference between the laser light emitted from the semiconductor laser 3 and the return light from the other end.

  In addition, the optical fiber 4 used here has a low propagation loss even when laser light is propagated beyond the coherent length. Furthermore, although the length of the optical fiber 4 here is a length exceeding the coherent length, it is set to a length that can effectively suppress attenuation during propagation.

The wavelength conversion element 5 has a waveguide 6 having a width of about 5 μm for guiding the laser light propagating through the optical fiber 4 described above, and is a nonlinear optical crystal that performs wavelength conversion. Here, in order to obtain a high-power visible light laser with high conversion efficiency, a LiNbO ₃ crystal (PPLN) employing a periodically poled structure is employed. In the optical fiber 4 described above, the other end opposite to the one end on the semiconductor laser 3 side is optically coupled to the waveguide 6 of the wavelength conversion element 5, and the laser beam emitted from the semiconductor laser 3. Is efficiently guided to the waveguide 6.

  The wavelength of the laser light that has passed through the waveguide 6 is converted and emitted as a visible light laser. Specifically, near-infrared laser light (a fundamental wave of visible blue light) emitted from the semiconductor laser 3 is wavelength-converted so that the laser light having a wavelength of 940 nm becomes the laser light having a wavelength of 470 nm. The near-infrared laser light (the fundamental wave of visible green light) emitted from the semiconductor laser 3 is wavelength-converted so that the laser light with a wavelength of 1060 nm becomes the laser light with 530 nm.

  Hereinafter, the manufacturing method of the visible light source device 1 will be described in detail.

<Method for Manufacturing Visible Light Source 1>
Hereinafter, the flowchart of the manufacturing method of the visible light source device 1 will be described with reference to FIG.

  First, in step S <b> 1, the semiconductor laser 3, the optical fiber 4, and the wavelength conversion element 5 are installed on the optical mount 2.

  In step S2, the optical fiber 4 is fixed to the optical mount 2 with the adhesive 7 described above. Further, the optical fibers 4 are fixed to each other by the adhesive 7. Here, the optical fiber 4 after being fixed is provided with a curved portion or a fixing portion by an adhesive 7, and residual stress is applied to the optical fiber 4 at the curved portion and its vicinity and at the fixing portion and its vicinity. It exists.

  In step S3, as described above, after all the elements are attached to the optical mount 2 and the optical fiber 4 is fixed, the curved portion of the optical fiber 4 and its vicinity, and the fixed portion of the optical fiber 4 and its vicinity As a target, the entire optical mount 2 of the visible light source device 1 is annealed. Here, the entire optical mount 2 is annealed, but the annealing is performed under conditions for the curved portion of the optical fiber 4 and the vicinity thereof, and the fixed portion of the optical fiber 4 and the vicinity thereof. Further, the conditions of the temperature and time for performing the annealing here are the melting point of the optical fiber 4 in the bent portion of the optical fiber 4 and the vicinity thereof, the fixed portion of the optical fiber 4 and the vicinity thereof, the degree of bending, and the structure This is a condition determined based on the heat conduction efficiency and the like, and is a temperature range condition that hardly damages other elements other than the optical fiber 4.

  Specifically, the annealing is performed by placing the entire optical mount 2 in a high temperature atmosphere exceeding the normal use temperature of the optical fiber 4 for 1 hour or longer. Here, the use temperature refers to a temperature in a use state in which the optical fiber 4 propagates laser light, and specifically, a temperature of about 45 ° C. In addition, the dispersion | distribution of the residual stress of the optical fiber 4 here becomes more effective dispersion | distribution by performing annealing at the temperature more than storage temperature. Here, the storage temperature refers to a temperature in a temperature range in which the function of the optical fiber 4 that propagates while stabilizing the polarization direction of the laser light is maintained, and specifically, a temperature in the range of 60 ° C. to 80 ° C. Say. In consideration of the heat resistance of other elements around the optical mount 2, annealing at a temperature equal to or higher than the storage temperature here is set to 60 ° C. in order to prevent thermal damage to these elements. It is preferable.

  In step S4, the entire optical mount 2 subjected to the annealing is allowed to cool for a while.

  In step S <b> 5, the entire optical mount 2 is attached to the visible light source device 1.

  As described above, annealing is performed after all elements are attached to the optical mount 2, so that the curved portion of the optical fiber 4 and the vicinity thereof and the residual stress in the fixed portion of the optical fiber 4 and the vicinity thereof are dispersed. A stable visible light output can be obtained immediately.

  In the visible light source device 1 manufactured by such a manufacturing method, the optical fiber 4 may be affected by thermal effects from the optical mount 2 and other parts and parts inside the visible light source device 1 in the vicinity thereof. However, the polarization direction and the refractive index of the light propagating through the annealed optical fiber 4 are stabilized. As described above, the visible light source device 1 with high reliability capable of obtaining a visible light laser having a stable output can be manufactured by the manufacturing method described above.

  Hereinafter, the stability of the polarization direction when the annealing described above is performed and the stability of the polarization direction when the annealing is not performed will be described with reference to graphs (FIGS. 3 and 4).

  Here, FIG. 3 shows how the SHG output fluctuates when the temperature condition of the visible light source device 1 manufactured without annealing is changed. FIG. 4 shows how the SHG output fluctuates when the temperature condition of the visible light source device 1 manufactured by annealing according to the above embodiment is changed.

  As shown in FIG. 3, in the visible light source device 1 that was not annealed, the SHG output fluctuated violently as the ambient temperature changed. On the other hand, as shown in FIG. 4, in the visible light source device 1 manufactured by performing the annealing, even if the ambient temperature is changed in the same manner as in the case where the annealing is not performed, the SHG output is reduced. The fluctuation was suppressed within 1%, and a stable visible light output could be obtained.

  Since the SHG output has a secondary characteristic of the input laser beam intensity, when annealing is not performed, the input laser beam intensity changes due to the fluctuation of the deflection state, thereby making the SHG output more stable. The problem of not happening. In other words, considering that the SHG output strongly modulates light in a predetermined deflection direction, even if the input laser beam intensity is the same, the SHG output changes because the deflection state changes, making it unsuitable as a light source in photographic processing. It has become.

<Features of Manufacturing Method of Visible Light Source 1>
(1)
In the method for manufacturing the visible light source device 1 according to the present embodiment, annealing is performed under conditions for the curved portion of the optical fiber 4 optically coupled to the semiconductor laser 3. For this reason, even if there is a residual stress in the curved portion of the optical fiber 4 optically coupled to the semiconductor laser 3, the residual stress is dispersed by annealing the curved portion. Thereby, even if ambient temperature and atmospheric pressure change, a change in the distribution of residual stress in the curved portion of the optical fiber 4 can be suppressed. As described above, since the polarization direction of the laser light propagated by the optical fiber 4 can be propagated to the waveguide 6 of the wavelength conversion element 5, fluctuations in the output of the visible light laser can be suppressed. Therefore, the visible light source device 1 capable of stabilizing the polarization direction of the laser light propagated by the optical fiber 4 can be manufactured even when the ambient temperature or pressure changes.

  Further, for example, when the curved portion is provided in the installation process of the optical fiber 4, the refractive index of the curved portion of the optical fiber 4 may change due to the influence of ambient temperature and atmospheric pressure. However, even if the ambient temperature and pressure change due to the above-described annealing, the change in the refractive index in the curved portion of the optical fiber 4 can be suppressed. Therefore, the visible light source device 1 capable of stabilizing the polarization direction of the laser light propagated by the optical fiber 4 can be manufactured even when the ambient temperature or pressure changes.

  Further, the above-described annealing is performed not only on the curved portion but also in the vicinity thereof, and also on the condition for the fixing portion of the optical fiber 4 as a target. As a result, the polarization direction of the laser light propagated by the optical fiber 4 can be more reliably stabilized even when the residual stress exists not only in the curved portion but also in the vicinity thereof, the fixed portion, and the vicinity thereof. Yes.

  Further, as described above, since the polarization direction of the laser light propagated by annealing is stabilized even when the optical fiber 4 is bent, the semiconductor laser 3 and the wavelength conversion element 5 coupled to the optical fiber 4 are stabilized. It is possible to improve the degree of freedom of arrangement. As the degree of freedom in arrangement of the semiconductor laser 3 and the wavelength conversion element 5 and the like is improved, the visible light source device 1 can be downsized.

  In addition, the visible light source device 1 of the present embodiment can reduce the number of components and can be less expensive than a conventional device that obtains second harmonics from a solid-state laser excited by laser light from a semiconductor laser. Can be manufactured.

  For example, the above-described visible light source device 1 may be incorporated as a printing (image forming) visible light source device (for example, a blue or green visible light monochromatic light source device) of a laser printer. In this case, even if the optical fiber 4 may be affected by heat from each part constituting the laser printer, the laser printing process is performed using the laser light whose polarization direction is stable and the visible light output is stable. And the stability of image formation can be improved.

(2)
In the method for manufacturing the visible light source device 1 of the present embodiment, the optical fiber 4 having a length exceeding the coherent length is used. For this reason, the reflected wave from the end portion is propagated through a length exceeding the coherent length, and becomes light with a disordered wavelength and phase. Thereby, interference between the reflected light from the end of the optical fiber 4 and the laser light from the semiconductor laser 3 is suppressed. Therefore, it is possible to obtain harmonic light having a stable output.

  Further, for example, when the optical fiber 4 having a length exceeding the coherent length is provided and the installation space in the visible light source device 1 is limited, a part of the optical fiber 4 is bent. It will be necessary to store in a predetermined area. However, even when the optical fiber 4 having a length exceeding the coherent length is curved and accommodated in this way, the residual stress in the curved portion is dispersed by annealing so that the polarization direction of the laser light is stabilized. It is possible to propagate as it is.

(3)
In the manufacturing method of the visible light source device 1 of this embodiment, the optical fiber 4 is annealed at a high temperature that is equal to or higher than the operating temperature. As a result, residual stress that cannot be dispersed simply by using the optical fiber 4 is also dispersed. Therefore, the residual stress of the optical fiber 4 can be effectively dispersed.

(4)
In the manufacturing method of the visible light source device 1 of this embodiment, annealing can be performed at a temperature in the storage temperature range that is higher than the use temperature. Thereby, the residual stress of the optical fiber 4 is effectively dispersed. Further, since the annealing is performed within the storage temperature range, loss of the propagation function of the optical fiber 4 can be prevented. Therefore, it is possible to prevent the loss of the propagation function of the optical fiber 4 while dispersing the residual stress of the optical fiber 4 more efficiently.

  In the case where the storage temperature range of the optical fiber 4 is about 60 to 80 ° C., the other elements of the visible light source device 1 are annealed at a lower temperature (for example, 60 ° C.) in the storage temperature range. Damage to the can be reduced.

(5)
In the manufacturing method of the visible light source device 1 of this embodiment, annealing is performed for 1 hour or more. Accordingly, heat can be sufficiently transmitted to the inside of the optical fiber 4, and not only the residual stress in the vicinity of the surface of the optical fiber 4 but also the residual stress in the optical fiber 4 is dispersed. Therefore, the residual stress of the optical fiber 4 can be more reliably dispersed.

<Other embodiments>
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to this, A various change like the modification shown below is possible in the range which does not deviate from the summary of invention.

(A)
In the method of manufacturing the visible light source device 1 according to the above embodiment, the optical fiber in the curved portion of the optical fiber 4 and the vicinity thereof, and the fixed portion of the optical fiber 4 and the vicinity thereof as the temperature and time conditions for annealing. The manufacturing method in which annealing is performed under conditions determined based on the melting point of 4 and the degree of bending, the heat conduction efficiency on the structure, and the like has been described by way of example.

  However, the present invention is not limited to this, and as a method for manufacturing the visible light source device 1, as shown in FIG. The manufacturing method may include itself.

  The flowchart of the specific manufacturing process here is almost the same as that in the above embodiment (steps S21, 22, 24, 25). However, here, as shown in FIG. 5, in step S23, the temperature and time conditions for annealing only the curved portion of the optical fiber 4 and its vicinity and the fixed portion of the optical fiber 4 and its vicinity are targeted. In addition, the temperature and time conditions for annealing are determined including the adhesive 7 to which the optical fiber 4 is fixed. Here, for example, conditions for annealing are determined in consideration of the melting point of the adhesive 7 and the like.

  Thus, the effects described below can be obtained by including the adhesive 7 as an object of annealing.

  First, depending on the properties of the adhesive 7, the adhesive 7 may expand and contract when affected by changes in ambient temperature. Then, the polarization direction of the laser beam changes due to the change in the residual stress distribution in the vicinity of the adhesive 7 of the optical fiber 4 due to the expansion and contraction of the adhesive 7, and the polarization direction remains stable. It may be difficult to propagate the laser light.

  On the other hand, here, the adhesive 7 that fixes the fixing portion of the optical fiber 4 optically coupled to the semiconductor laser 3 is also included in the object to determine the conditions for performing the annealing. Residual stress is prevented from occurring in the optical fiber 4 in the vicinity of the adhesive 7 due to the expansion and contraction of the agent 7. Thereby, even if the surrounding air temperature and pressure change, the change in the distribution of residual stress in the vicinity of the adhesive 7 of the optical fiber 4 can be suppressed. In this way, it is possible to propagate to the waveguide 6 of the wavelength conversion element 5 while stabilizing the polarization direction of the laser light propagated by the optical fiber 4, and it is possible to suppress fluctuations in the output of the visible light laser. Therefore, the visible light source device 1 capable of stabilizing the polarization direction of the laser light propagated by the optical fiber 4 can be manufactured even when the ambient temperature or pressure changes.

  Further, for example, when the adhesive 7 is used in the installation process of the optical fiber 4, the refractive index in the vicinity of the adhesive 7 of the optical fiber 4 may change due to the influence of changes in ambient temperature and pressure. . However, even if the ambient temperature and pressure change due to the above-described annealing, the change in the refractive index in the vicinity of the adhesive 7 of the optical fiber 4 can be suppressed. Therefore, the visible light source device 1 capable of stabilizing the polarization direction of the laser light propagated by the optical fiber 4 can be manufactured even when the ambient temperature or pressure changes.

  Further, in the installation process of the optical fiber 4, when the optical fiber 4 is pulled and both ends thereof are fixed, the optical fiber 4 may be stretched and the polarization direction and the refractive index may not be stable. is there. In such a case, the polarization direction and the refractive index can be stabilized by performing the same annealing as described above for the portion where the elongation strain of the optical fiber 4 exists.

(B)
In the manufacturing method of the visible light source device 1 according to the above-described embodiment, an example of the temperature condition and the time condition when performing the annealing has been described.

  However, the present invention is not limited to this, and as long as the residual stress of the optical fiber 4 can be effectively diffused, the temperature condition and the time condition for annealing are other than those in the above embodiment. Condition may be sufficient.

  Various factors relating to the optical fiber 4 can be considered as appropriate values for the temperature condition and the time condition for annealing. For this reason, the temperature condition and time condition for annealing are appropriately determined according to the type of optical fiber (quartz, multicomponent, plastic, etc.), optical fiber hardness, glass crystal thickness, residual stress level, etc. It may be changed.

  According to the present invention, it becomes possible to improve the stability of the polarization direction of the laser light propagated by the optical fiber, and therefore, the laser device that propagates the laser light using the optical fiber and the manufacturing method thereof can be applied. It is particularly useful.

The block diagram of the optical mount periphery in a visible light source device. The flowchart which shows the manufacturing process of the visible light source device which concerns on this embodiment. The figure which shows the fluctuation | variation of the visible light output with respect to atmospheric temperature when not performing annealing. The figure which shows the fluctuation | variation of the visible light output with respect to atmospheric temperature at the time of performing annealing. The flowchart which shows the manufacturing process of the visible light source device which concerns on other embodiment (A).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Visible light source device 2 Optical mount 3 Semiconductor laser (laser light source)
4 Optical fiber 5 Wavelength conversion element 6 Waveguide 7 Adhesive (fixing member)

Claims (7)

Optically coupling an optical fiber to a laser light source;
Bending at least a portion of the optical fiber;
Annealing by placing the curved portion of the optical fiber in an atmosphere of a predetermined temperature or more;
A method for manufacturing a laser device comprising: Optically coupling an optical fiber to a laser light source;
Fixing at least a part of the optical fiber via a fixing member;
Annealing by placing the vicinity of the fixing member of the optical fiber and the fixing member in an atmosphere of a predetermined temperature or more;
A method for manufacturing a laser device comprising: The optical fiber has a length exceeding the coherent length;
A method for manufacturing the laser device according to claim 1. The predetermined temperature in the case of performing the annealing is a temperature equal to or higher than a use temperature at the time of use of the optical fiber heated when propagating a laser beam.
The method for manufacturing a laser device according to any one of claims 1 to 3. The predetermined temperature when the annealing is performed is a temperature that is equal to or higher than the use temperature and equal to or higher than an upper limit temperature of a storage temperature range of the optical fiber.
The manufacturing method of the laser apparatus of Claim 4. The annealing is performed for 1 hour or more.
The method for manufacturing a laser device according to claim 1. It is manufactured by the method for manufacturing a laser device according to any one of claims 1 to 6.
Laser device.

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