JP2007305902A - Laser module and its assembling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the destruction of an optical fiber and the deterioration of a laser beam output caused by the roughened surface of the incidence end surface of the optical fiber and the like, in a laser module where a laser beam emitted from a laser such as a semiconductor laser is made incident into an optical fiber, and the laser beam is emitted from the optical fiber while the incidence end surface of the optical fiber is covered with a transparent member. <P>SOLUTION: The laser module comprises: a laser light source 11; a convergence optical system 12 for condensing a laser beam B emitted from the laser light source 11; an optical fiber 13 arranged in a position where the laser beam B condensed by the convergence optical system 12 is accepted from an incidence end surface 13a while an end surface is used as the incidence end surface 13a; and a ferrule 14 where the vicinity of the incident end surface of this optical fiber 13 is fixedly accommodated at least. In the laser module, a transparent member 15 is joined to the end surface 14a of the ferrule 14 matched with the incidence end surface 13a of the optical fiber 13. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a laser module, and more particularly to a laser module in which a laser beam emitted from a laser such as a semiconductor laser is incident on an optical fiber and the laser beam is emitted from the optical fiber.

  The present invention also relates to an apparatus for assembling the laser module as described above.

  Conventionally, as disclosed in, for example, Patent Document 1, laser beams emitted from a plurality of semiconductor lasers are collected by a condensing optical system and incident on an optical fiber, and one laser combined from the optical fiber A laser module that emits a beam is known.

  When such a laser module is used as an exposure light source for an image exposure apparatus or a recording light source for an image recording apparatus, a small semiconductor laser has been widely used as the laser. As a result, the laser module that condenses the laser beam emitted from one semiconductor laser by the condensing optical system and enters the optical fiber and emits the laser beam from the optical fiber is also provided. Has been. Patent Document 1 also discloses a laser module that uses one laser as such.

  By the way, in the laser module having the above configuration, when a short wavelength laser having an oscillation wavelength of about 350 to 500 nm is applied, the light of the optical components in the laser module is collected due to the dust collection effect by the high energy short wavelength laser beam. There is a problem (so-called laser contamination) that contaminants tend to adhere to the passage end face. Naturally, the same applies to the incident end face of the optical fiber. Therefore, as shown in Patent Document 1, the incident end face of the optical fiber is placed against a transparent member such as glass through which the laser beam passes, and contaminants adhere to the incident end face of the optical fiber. It has been proposed to prevent this.

In that case, in order to ensure the strength of the incident end of the optical fiber, the vicinity of the incident end face of the optical fiber is accommodated and fixed in the ferrule, and the incident end face of the optical fiber is abutted against the transparent member together with the ferrule. It has become common. In addition, without using such a ferrule, the incident end face of the optical fiber is directly heated and joined to the transparent member.
JP 2004-253783 A

  As described above, the structure in which the incident end face of the optical fiber is disposed to abut against a transparent member such as glass can achieve the intended purpose of preventing contamination from adhering to the incident end face of the optical fiber. On the other hand, it can lead to other problems.

  That is, in the structure in which the incident end face of the optical fiber is abutted against the transparent member together with the ferrule, the incident end face of the optical fiber and the transparent member are not particularly joined. Since the laser beam is irradiated on the contact surface, a part of both may be weakly bonded. If so, when a force acting to separate them due to thermal stress due to vibration or temperature change is applied, the weakly joined part is peeled off, and the peeled surface is a rough surface. This causes a problem that the laser beam is difficult to transmit. Such a situation leads to a decrease in the output of the laser beam emitted from the laser module.

  On the other hand, in the structure in which the incident end face of the optical fiber is directly heated and joined to the transparent member without using a ferrule, the strength of the optical fiber is not sufficient, and the optical fiber is broken due to vibration during handling of the laser module or transportation The problem of being easy to do is recognized.

  The present invention has been made in view of the above circumstances, and a laser capable of preventing a decrease in output of a laser beam due to roughening of an incident end face of an optical fiber or a laser beam passing portion of a transparent member, and destruction of the optical fiber. The purpose is to provide modules.

  It is another object of the present invention to provide an assembling apparatus capable of efficiently assembling the above laser module in the best state.

The laser module according to the present invention comprises:
A laser light source;
A condensing optical system for condensing a laser beam emitted from the laser light source;
An optical fiber disposed at a position where one end surface is an incident end surface and receives the laser beam condensed by the condensing optical system from the incident end surface;
In a laser module comprising a ferrule that accommodates and fixes at least a portion near the incident end face of the optical fiber,
A transparent member is bonded to the end face of the ferrule that matches the incident end face of the optical fiber so that the light beam condensed by the condensing optical system enters the incident end face of the optical fiber via the transparent member. It is characterized by having been comprised.

In the laser module according to the present invention, it is desirable that the ferrule and the transparent member are made of a material having a difference in thermal expansion coefficient of 3 × 10 ⁻⁶ [1 / K] or less. In doing so, it is most preferable that the ferrule and the transparent member are formed of the same material.

  Further, it is desirable that the end face of the ferrule aligned with the incident end face of the optical fiber and the transparent member are so-called room temperature bonded. The “room temperature bonding” is a bonding state obtained by applying pressure after two smooth bonded surfaces are highly cleaned by plasma cleaning and / or ultraviolet cleaning. When this room temperature bonding is applied, it is desirable that the incident end face of the optical fiber is similarly bonded to the transparent member at the room temperature in addition to the end face of the ferrule.

  In addition, after performing the above-mentioned joining, if the light of a short wavelength is irradiated to two joining surfaces, the joining will become more stable. Such light may be irradiated before the laser module is put into actual use, or a laser beam is irradiated onto the joint surface between the incident end face of the optical fiber and the transparent member in accordance with the actual use of the laser module. Therefore, when the laser beam has a short wavelength, it is possible to stabilize the room temperature bonding by using the laser beam.

  However, in the laser module of the present invention, the end face of the ferrule and the transparent member, or the end face of the ferrule and the incident end face of the optical fiber and the transparent member may be joined in other forms without being limited to room temperature joining. Examples of such bonding forms include potting (casting sealing), heat bonding, anodic bonding, and adhesion.

  Further, the present invention is particularly preferably applied to a laser module having a semiconductor laser that emits a laser beam having a wavelength in the range of 350 to 500 nm as a laser light source.

Further, a laser module according to the present invention includes a laser holder having a laser holding portion for holding the laser light source, and an optical system holder accommodating portion in which a sliding surface extending in the optical axis direction of the laser light source is formed,
It is desirable that the optical system holder further includes an optical system holder that holds the condensing optical system and is accommodated in a portion where the sliding surface of the optical system holder accommodating portion is formed.

On the other hand, a laser module assembling apparatus according to the present invention is for assembling a laser module that further includes the above-mentioned laser holder and optical system holder,
Laser holder holding means for holding the laser holder;
An optical system holder holding means for holding the optical system holder in a state of being accommodated in an optical system holder housing portion of the laser holder;
A fiber end holding means that holds the ferrule accommodating and fixing the optical fiber and / or the transparent member bonded to the ferrule, and is movable by a minute amount in the axial direction of the optical fiber;
An alignment means capable of adjusting the laser holder holding means and the optical system holder holding means in a direction in which the optical axis of the condensing optical system coincides with the axial direction of the optical fiber;
And a photodetector for detecting the light intensity of the laser beam emitted from the emission end face which is the other end face of the optical fiber.

The alignment means described above is
It has a part of a spherical surface and a concave part that is slidably and closely combined with a part of the spherical surface,
One of the spherical surface and one of the concave surface portions is placed between the other and the normal fiber is aligned in the axial direction of the optical fiber held by the fiber end holding means. Placed in a state facing each other,
It is desirable that a part of the spherical surface and the other of the concave surface portion are connected to the laser holder holding means.

  In the laser module of the present invention, since the transparent member joined to the end face of the ferrule also covers the incident end face of the optical fiber, it is possible to prevent contaminants from adhering to the incident end face of the optical fiber from the outside.

  In this laser module, since the transparent member is bonded to the end face of the ferrule having a thicker optical fiber fixed thereto, the transparent member can be easily removed from the ferrule even when thermal stress due to vibration or temperature change acts. It will not peel off. Therefore, even if the incident end face of the optical fiber and the transparent member are naturally weakly bonded for the reasons described above, they are prevented from peeling off. Therefore, the incident end face of the optical fiber or the peeled surface of the transparent member becomes rough and it is difficult for the laser beam to pass therethrough, so that it is possible to reliably prevent the output of the laser beam from decreasing.

  Further, since at least the vicinity of the incident end face of the optical fiber is accommodated and fixed by the ferrule, the optical fiber is reinforced by the ferrule, so that the optical fiber can be easily broken by vibration during handling or transportation of the laser module. Disappears.

In the laser module according to the present invention, when the difference between the thermal expansion coefficients of each other is 3 × 10 ⁻⁶ [1 / K] or less, particularly because the ferrule and the transparent member are made of the same material. Since it is possible to suppress the generation of thermal stress in a high or low temperature environment, the reliability of the laser module with respect to temperature changes can be improved.

  In addition, in a laser module equipped with a semiconductor laser that emits a short-wavelength laser beam having a wavelength in the range of 350 to 500 nm as a laser light source, an optical fiber is incident due to a dust collection effect by a high-energy short-wavelength laser beam. Contaminants easily adhere to the end face and the light passing end face of the transparent member. Therefore, when the present invention is applied to such a laser module, it is possible to effectively prevent a decrease in the output of the laser beam due to laser contamination.

  In addition, a laser module according to the present invention includes a laser holder having a laser holding portion for holding a laser light source, an optical system holder housing portion having a sliding surface extending in the optical axis direction of the laser light source, and the light condensing If the optical system holder is further provided with an optical system holder that is accommodated in the portion of the optical system holder accommodating portion where the sliding surface is formed, the laser module assembling apparatus of the present invention, which will be described later, can improve efficiency. It can be assembled in the best condition.

That is, the laser module assembling apparatus according to the present invention is for assembling a laser module that further includes the above-mentioned laser holder and optical system holder,
Laser holder holding means for holding the laser holder;
An optical system holder holding means for holding the optical system holder in a state of being accommodated in an optical system holder housing portion of the laser holder;
A fiber end holding means that holds the ferrule accommodating and fixing the optical fiber and / or the transparent member bonded to the ferrule, and is movable by a minute amount in the axial direction of the optical fiber;
An alignment means capable of adjusting the laser holder holding means and the optical system holder holding means in a direction in which the optical axis of the condensing optical system coincides with the axial direction of the optical fiber;
And a photodetector for detecting the intensity of the light emitted from the exit end face which is the other end face of the optical fiber, so that the laser holder holding means and the optical system holder holding means are In a state where the optical axis is adjusted to coincide with the axial direction of the optical fiber, the fiber end holding means can move the ferrule and the transparent member bonded thereto in minute amounts in the axial direction of the optical fiber. ing. Therefore, every time the ferrule and the transparent member bonded to the ferrule are moved as described above, if the light intensity of the laser beam emitted from the emission end face of the optical fiber is detected by the photodetector, the ferrule having the maximum light intensity is obtained. And the moving position of the transparent member can be found. Since the moving position of the ferrule and the transparent member is a position where the laser beam is coupled to the optical fiber fixed to the ferrule with the maximum efficiency, the ferrule and the transparent member, the laser holder, and the optical system holder are in that state. If the relative position is fixed, it is possible to assemble the laser module in the best condition where the laser beam is coupled to the optical fiber with maximum efficiency.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a partially broken side view of a laser module according to an embodiment of the present invention. As shown in the figure, this laser module 10 includes a semiconductor laser 11 in a chip state as a laser light source, a condensing lens 12 for condensing a laser beam B emitted from the semiconductor laser 11, an end surface at an incident end surface 13a, and the like. The end face is an emission end face 13b, and the optical fiber 13 disposed at a position for receiving the laser beam B condensed by the condenser lens 12 from the incident end face 13a, and at least the vicinity of the incident end face of the optical fiber 13 are accommodated and fixed. It has a glass ferrule 14, and an incident end face 13a of the optical fiber 13 and a transparent member 15 joined to the rear end face 14a of the ferrule 14 aligned therewith.

  The semiconductor laser 11 is, for example, a multimode broad area laser having an emission width of 10 μm and an output of 500 mW. The semiconductor laser 11 is disposed in a so-called CAN package 20 including a substantially disc-shaped stem 16, a cap 17, and a window glass 18 that closes a light exit window 17 a of the cap 17. In other words, a heat block 19 made of copper or the like with good heat dissipation is fixed to the stem 16, and the semiconductor laser 11 is mounted on the heat block 19 using, for example, an AuSn brazing material. After the semiconductor laser 11 is mounted in this manner, the cap 17 is joined to the stem 16 by, for example, low resistance welding, and the inside of the CAN package 20 is sealed. Note that it is desirable to fill the inside of the CAN package 20 with an inert gas.

  The semiconductor laser 11 is connected to a semiconductor laser drive circuit (not shown) outside the package via a lead 21 that penetrates the stem 16. The CAN package 20 is held in a stainless steel laser holder 30 having a cylindrical portion 30a and a flange portion 30b. That is, the cylindrical portion 30a serves as a laser holding portion, and the stem 16 of the CAN package 20 is press-fitted and fixed to the inner peripheral surface thereof. Note that the stem 16 can be fixed to the cylindrical portion 30a by welding such as YAG welding, solder, adhesive, or the like instead of such press-fitting.

  The inner peripheral surface of the cylindrical portion 30a of the laser holder 30 extends in the optical axis direction of the semiconductor laser 11 when the CAN package 20 (that is, the semiconductor laser 11) is held there as described above. However, the cylindrical portion 30a also constitutes an optical system holder accommodating portion. That is, the condenser lens 12 is bonded and fixed in the cylindrical portion 31a of the optical system holder 31 having the cylindrical portion 31a and the flange portion 31b, and the cylindrical portion 31a is fitted in the cylindrical portion 30a of the laser holder 30. It is fixed. Here, the condensing lens 12 may be fixed to the cylindrical portion 31a by press fitting or the like in addition to bonding. As the condenser lens 12 of this example, a lens having a magnification of 4 is used.

  As the optical fiber 13, a multimode fiber having an NA of 0.22 and a core diameter of 50 μm is applied. On the other hand, the incident NA of the laser beam B condensed by the condenser lens 12 is 0.2. For example, the transparent member 15 is made of glass having a refractive index of 1.5 and a thickness (size in the light traveling direction) of about 1.0 mm. In this case, the NA of the laser beam B inside the transparent member 15 is 0.127.

  The portion of the optical fiber 13 close to the incident end face 13 a is stripped to have a bare wire state, and that portion is accommodated and fixed in the ferrule 14. The rear end face 14a of the ferrule 14 and the incident end face 13a of the optical fiber 13 are joined to the front end face 15a of the transparent member 15 by the above-described normal temperature joining. That is, the rear end surface 14a and the incident end surface 13a and the front end surface 15a of the transparent member 15 are subjected to a smoothing process, washed with ultraviolet rays, and then firmly bonded together by pressing with an appropriate pressure. The

In the present embodiment, the ultraviolet ray cleaning apparatus UV-312 manufactured by Technovision Co., Ltd. is used, and the above ultraviolet ray cleaning is performed by irradiating ultraviolet rays having a peak wavelength of 253.7 nm / 184.9 nm and a power density of 10 mW / cm ² for 1000 seconds. Went.

It should be noted that a more stable bonding state can be obtained by irradiating the bonding surface with light having a short wavelength during pressurization in the room temperature bonding. In the case of this embodiment, since the ferrule 14 is transparent glass, it can be transmitted therethrough to irradiate a light beam having a short wavelength from an oblique direction onto the joint surface. Specifically, in this example, ultraviolet rays having a wavelength of 405 nm and a power density of 1100 W / mm ² were irradiated for 4 hours. Alternatively, a short wavelength light beam may be irradiated from the output side of the optical fiber 13. When doing so, the fiber core portion is irradiated with light having high luminance, so that very stable bonding can be obtained.

  FIG. 4 shows the irradiation conditions (ultraviolet irradiation time and power density) at which stable bonding is obtained when irradiating the ultraviolet rays having the wavelength of 405 nm. While stable bonding can be obtained under conditions on the right side of the straight line in the figure, stable bonding cannot be obtained under conditions on the left side of the straight line.

  The transparent member 15 is formed in a substantially cylindrical shape, and is accommodated and fixed in the transparent member holder 32. The transparent member holder 32 is fixed to the optical system holder 31. These holders 32 and 31 are also made of stainless steel as an example, and both of them are fixed by YAG welding. In addition, you may perform those fixation using an adhesive agent or solder other than YAG welding.

  In the laser module 10 of the present embodiment having the above configuration, the laser beam B emitted from the semiconductor laser 11 is collected by the condenser lens 12 and converged on the incident end face 13 a of the optical fiber 13. Therefore, the laser beam B enters the core (not shown) of the optical fiber 13 from the incident end face 13a, is guided there, and is emitted from the outgoing end face 13b of the optical fiber 13.

  When the transparent member holder 32 is fixed to the optical system holder 31, the laser beam emitted from the emission end surface 13 b of the optical fiber 13 while moving the transparent member holder 32 on the front end surface 31 c of the optical system holder 31. The light intensity of B is detected, and the transparent member holder 32 is fixed at a position where the light intensity becomes maximum.

  In the laser module 10 of this embodiment, since the transparent member 15 is bonded to the incident end face 13a of the optical fiber 13 and the rear end face 14a of the ferrule, it is possible to prevent contaminants from adhering to the incident end face 13a from the outside. Is done. Therefore, it is possible to reliably prevent the output of the laser module 10 from being lowered due to the laser contamination as described above. In particular, in this embodiment, when the transparent member 15 is bonded to the incident end face 13a of the optical fiber 13 at room temperature, the bonded surfaces are irradiated with high-intensity short-wavelength light, so that very stable bonding is obtained. . Thereby, the possibility of laser contamination of the joint between the incident end face 13a of the optical fiber 13 and the transparent member 15 during actual use of the laser module 10 is suppressed to a very low level, and high reliability is obtained.

  Further, in this example, the wavelength of the laser beam B is around 400 nm, and laser contamination is likely to occur as described above. Therefore, it is possible to particularly effectively prevent a decrease in output due to this laser contamination.

  In this laser module 10, the transparent member 15 is bonded not only to the incident end face 13a of the optical fiber 13 but also to the incident end face 13a and the rear end face 14a of the ferrule 14 aligned therewith. Even if thermal stress acts, the transparent member 15 and the optical fiber 13 are not easily separated. Therefore, both of them are peeled off, and the peeled surface becomes a rough surface, so that the laser beam B is difficult to be transmitted. Therefore, it is possible to prevent the output of the laser beam B from being lowered.

  Further, since at least the vicinity of the incident end face of the optical fiber 13 is accommodated and fixed by the ferrule 14, the optical fiber 13 is reinforced by the ferrule 14, and therefore the optical fiber 13 is caused by vibration during handling or transportation of the laser module 10. It wo n’t be easily destroyed.

  And in the laser module 10 of this embodiment, since the ferrule 14 and the transparent member 15 are especially formed from the same glass, the thermal expansion coefficients of both of them are substantially equal. Therefore, since generation of thermal stress in a high or low temperature environment can be suppressed, the reliability of the laser module 10 with respect to temperature changes is also high.

More specifically, when the ferrule 14 and the transparent member 15 are formed of materials having a difference in thermal expansion coefficient between each other of 3 × 10 ⁻⁶ [1 / K] or less, the above-described effect can be obtained remarkably. . In particular, when the transparent member 15 and the incident end face 13a of the optical fiber 13 are joined as in this embodiment, the optical fiber 13 in addition to the ferrule 14 and the transparent member 15 has a difference in thermal expansion coefficient of 3 between each other. It is desirable to be formed from a material of × 10 ⁻⁶ [1 / K] or less. When the transparent member 15 and the optical fiber 13 are made of materials having a difference in thermal expansion coefficient of 3 × 10 ⁻⁶ [1 / K] or less, in the example where the shape of the joint portion is 30 μm in diameter, The displacement in the lateral direction (direction perpendicular to the axis of the optical fiber 13) due to thermal expansion when there is a temperature change of ℃ is 4.5 × 10 ⁻³ μm or less, and an extremely stable bonding state can be obtained. confirmed. The above is not limited to the case where the transparent member 15 and the optical fiber 13 are bonded at room temperature, but can be similarly applied to the case where they are bonded by other bonding or the like.

  In the present embodiment, the rear end surface (incident end surface) of the transparent member 15 is an inclined surface inclined by a predetermined angle with respect to the optical axis of the condenser lens 12. By doing so, it is possible to prevent the laser beam B reflected at the rear end face from returning to the semiconductor laser 11 by following the optical path up to the rear end face and generating so-called return light noise there.

  Next, referring to FIG. 2, a laser module 100 according to another embodiment of the present invention will be described. In FIG. 2, the same elements as those in FIG. 1 are denoted by the same reference numerals, and the description thereof will be omitted unless necessary (the same applies hereinafter).

  The laser module 100 of this embodiment differs from the laser module 10 of FIG. 1 in that the rear end surface 14a of the ferrule 14 and the front end surface 15a of the transparent member 15 are joined by potting. That is, on the outer peripheral surfaces of the ferrule 14 and the transparent member 15, the potting resin 35 is dropped between the former rear end surface 14a and the latter front end surface 15a, and the resin penetrates between the both end surfaces 14a and 15a. As a result, the end faces are joined to each other. Further, the end faces of the optical fiber 13 and the transparent member 15 are in contact with each other without being joined.

  As the potting resin, a resin having a certain degree of high viscosity is selected and used so that it does not enter the incident end face 13a of the optical fiber 13. In addition, it is preferable to appropriately chamfer the edges of the rear end surface 14a of the ferrule 14 and the front end surface 15a of the transparent member 15 so that potting resin can easily enter between the two. Further, such bonding by potting may be performed in combination with the room temperature bonding described above, thereby obtaining a very strong bonding state.

  Furthermore, an adhesive having a relatively low viscosity may be allowed to enter between the rear end surface 14a of the ferrule 14 and the front end surface 15a of the transparent member 15, thereby bonding the end surfaces 14a and 15a. In that case, an annular groove located outside the optical fiber 13 is formed in both or one of the end faces 14a and 15a, and excess adhesive is trapped there, so that the adhesive with low viscosity is used in the optical fiber. It is desirable not to reach the 13 incident end faces 13a.

Note that when a high-luminance short-wavelength region beam is focused on an optical fiber having a small core diameter, the power density of the optical fiber incident end face (more specifically, the core end face) increases, and contamination tends to occur. Experimentally and empirically, it has been found that if this power density is about 10 W / mm ² or less, contamination is difficult. In the configuration shown in FIGS. 1 and 2, when the output of the semiconductor laser 11 is 500 mW, the refractive index of the transparent member 15 is 1.5, and the thickness is 1.0 mm, the power density of the optical fiber incident end face is about 10 W. since the / mm ^2, the thickness of the transparent member 15 is preferably set to more than 1.0 mm.

On the other hand, when the output of the semiconductor laser 11 is 1 W, similarly, when the refractive index of the transparent member 15 is 1.5 and the thickness is 1.4 mm, the power density of the optical fiber incident end face is about 10 W / mm ^2. Therefore, in that case, the thickness of the transparent member 15 is desirably 1.4 mm or more.

  Next, an embodiment of an apparatus for assembling the laser module 10 or 100 described above will be described with reference to FIG. In addition, although the case where the laser module 10 is assembled is described as an example here, the process is basically the same when the laser module 100 is assembled.

  The laser module assembling apparatus 300 shown in FIG. 3 includes a table 40, a swing table 50 having a lower surface P that forms a part of a spherical surface, and the table 40 fixed to the upper portion, and a lower surface P that is slidable. A spherical receiver 51 having a concavely shaped upper surface Q closely combined, a clamp 144 connected to the table 40 and constituting a laser holder holding means together with the table 40, and an optical system holder holding means for holding the optical system holder 31 45, a fiber end holding means 46 that holds the transparent member holder 32, and a laser power meter 48 that detects the light intensity of the laser beam B emitted from the optical fiber 13.

  The spherical receiver 51 is arranged in such a manner that one normal line of the concave surface faces the z direction and faces the optical fiber 13 with the oscillating base 50 interposed therebetween. In the apparatus 300, the clamp 144 for fixing the laser holder 30 is connected to the spherical receiver 51 side. The tip surfaces facing the lower side of these clamps 144, that is, the portions for suppressing the flange portions 30 of the laser holder 30, are formed so as to be oriented at right angles to the z direction.

  The fiber end holding means 46 holds the end of the optical fiber 13 indirectly by holding the transparent member holder 32, and each minute amount in the axial direction (arrow z direction) of the held optical fiber 13. It is configured to be movable, and further movable in two directions orthogonal to the z direction, that is, in the directions of the arrows x and y. The z direction is a direction perpendicular to the lower surface of the spherical receiver 51, and this is the reference direction.

  On the other hand, the optical system holder holding means 45 holds the optical system holder 31 by gripping the vicinity of the flange portion 31b of the optical system holder 31, and can move in synchronization with the fiber end holding means 46 in the z direction. Is formed.

  Next, the operation of the laser module assembling apparatus 300 having the above configuration will be described. First, in a pre-assembly process by this apparatus, the CAN package 20 is fixed in advance in the laser holder 30, the condenser lens 12 is fixed to the optical system holder 31, and the transparent member holder 32 is fixed to the transparent member 15. Then, the optical system holder 31 is incorporated into the cylindrical portion 30 a of the laser holder 30, and the laser holder 30 is set on the table 40 in this state.

  Next, the clamp 144 is actuated, and the flange portion 30 of the laser holder 30 is held down from above by the tip surface of the clamp 144. At this time, if the laser holder 30 on the table 40 is in a state in which the cylinder axis direction does not coincide with the z direction, the flange portion 30 is held down by the clamp 144 as described above, whereby the swing base 50 Slides on the spherical receiver 51 and swings around the x-axis and / or the y-axis, and the laser holder 30 is held in a state where its cylindrical axis direction coincides with the z-direction. Thereafter, the swing base 50 is locked by a lock mechanism (not shown) so as to maintain this state.

  Thus, the laser holder 30 is held on the table 40 in a state where the optical axis directions of the semiconductor laser 11 and the condenser lens 12 coincide with the axial direction of the optical fiber 13.

  Next, the optical system holder 31 is held by the optical system holder holding means 45 while maintaining the above state, and the transparent member holder 32 is held by the fiber end holding means 46. Next, the fiber end holding means 46 is moved in the z direction (downward direction), and the transparent member holder 32 is pressed against the front end face 31 c of the optical system holder 31. It is desirable that the pressure contact force at this time is detected by a load measuring means such as a load cell installed on the optical system holder 31 or the table 40 so that the pressure contact force is set to an appropriate value.

  Next, with the pressure contact maintained, the optical system holder holding means 45 and the fiber end holding means 46 are pitch-shifted by a minute amount in the z direction by a driving means (not shown). This movement is, for example, an upward direction, and the movement pitch is, for example, about 5 to 10 μm. As the optical system holder holding means 45 and the fiber end holding means 46 move, the transparent member holder 32 and the optical system holder 31 move in pitch. The optical system holder 31 is moved within the cylindrical portion 30 a of the laser holder 30. Since it moves while sliding, the distance between the semiconductor laser 11 and the condenser lens 12 can be changed. The moving direction of the optical system holder 31 is the axial direction of the optical fiber 13 that is indirectly held by the fiber end holding means 46 by setting the direction of the optical system holder 31 as described above. Matches.

  As described above, when the transparent member holder 32 and the optical system holder 31 are pitch-moved, the semiconductor laser 11 is continuously driven, and is emitted from the optical fiber 13 each time the holders 32 and 31 are stopped. The light intensity of the laser beam B is detected by a laser power meter 48. While detecting the light intensity, the fiber end holding means 46 (that is, the optical fiber 13) is moved in a predetermined range in the x and y directions, and the maximum light intensity obtained within the moving range is determined for each pitch movement. Recorded or stored for each stop position.

  The pitch movement of the transparent member holder 32 and the optical system holder 31 and the detection of the maximum light intensity at each stop position are performed over a predetermined range in the z direction. When that is finished, the stop position where the maximum value is obtained among the detected maximum light intensities is obtained, and the transparent member holder 32 and the optical system holder 31 are set to the stop positions. In this state, the distance between the semiconductor laser 11 and the condensing lens 12 is optimal, that is, the converging position of the laser beam B condensed by the condensing lens 12 is precisely the incident end face 13a of the optical fiber 13. It is a state that exists above. Therefore, the optical system holder 31 is fixed to the laser holder 30 while maintaining this state. This fixing is performed by, for example, YAG welding, but may be performed using an adhesive or the like.

  Next, the fiber end holding means 46 is moved by a predetermined range in the x and y directions with respect to the optical system holder holding means 45, and the fiber end holding at which the light intensity of the laser beam B detected by the laser power meter 48 is maximized. The x and y direction positions of the means 46 are obtained. The transparent member holder 32 is fixed to the optical system holder 31 in a state where the fiber end holding means 46 (that is, the optical fiber 13) is maintained at the position in the x and y directions. This fixing is also performed by, for example, YAG welding, but may be performed using an adhesive or the like.

  In addition, when the pitch movement of the transparent member holder 32 and the optical system holder 31 and the detection of the maximum light intensity at each stop position are performed, the position in the x and y directions of the fiber end holding means 46 from which the maximum light intensity is obtained is recorded. Alternatively, it may be stored, and when the transparent member holder 32 is fixed to the optical system holder 31, the fiber end holding means 46 may be set at the recorded or stored position in the x and y directions. However, when YAG welding is applied to fix the laser holder 30 and the optical system holder 31, the optical system holder 31 may move by a small amount in the x and y directions. In fixing to 31, it is preferable to obtain the position in the x and y directions of the fiber end holding means 46 at which the light intensity of the laser beam B is maximized again as described above.

  In the laser module assembling apparatus 300 described above, the optical system holder 31 is configured to move only in the z direction. However, the optical system holder 31 can be moved in the x and y directions for alignment. A mechanism may be applied.

  In the laser module assembling apparatus 300 described above, the laser holder 30 and the optical system holder 31 are swung with respect to the optical fiber 13, so that the optical axes of the semiconductor laser 11 and the condenser lens 12 are adjusted. The alignment is made to coincide with the axis, but conversely, it is also possible to perform the alignment by swinging the fiber end holding means 46 holding the optical fiber 13.

  Further, in the laser module according to the present invention, the ferrule 14 and the transparent member 15 may be accommodated in the cylindrical sleeve 60 as in the laser module 10 ′ of the embodiment shown in FIG. In that case, it is desirable to fix the ferrule 14 and the transparent member 15 to the sleeve 60 by, for example, bonding a part of the peripheral surface of the ferrule 14 to the end surface of the sleeve 60 with the adhesive 61.

The partially broken side view of the laser module by one Embodiment of this invention The partially broken side view of the laser module by another embodiment of this invention The partially broken side view of the laser module assembly apparatus by one Embodiment of this invention Graph showing UV irradiation conditions for room temperature bonding The partially broken side view of the laser module by another embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 10 ', 100 Laser module 11 Semiconductor laser 12 Condensing lens 13 Optical fiber 14 Ferrule 15 Transparent member 30 Laser holder 31 Optical system holder 32 Transparent member holder 35 Resin for potting 40 Table 45 Optical system holder holding means 46 Fiber end part Holding means 48 Laser power meter 144 Clamp 300 Laser module assembling apparatus

Claims (9)

A laser light source;
A condensing optical system for condensing a laser beam emitted from the laser light source;
An optical fiber disposed at a position where one end surface is an incident end surface and receives the laser beam condensed by the condensing optical system from the incident end surface;
In a laser module comprising a ferrule that accommodates and fixes at least a portion near the incident end face of the optical fiber,
A transparent member is bonded to the end face of the ferrule that matches the incident end face of the optical fiber so that the light beam condensed by the condensing optical system enters the incident end face of the optical fiber via the transparent member. A laser module characterized by being configured. 2. The laser module according to claim 1, wherein the ferrule and the transparent member are formed of a material having a difference in thermal expansion coefficient of 3 × 10 ⁻⁶ [1 / K] or less.   3. The laser module according to claim 2, wherein the ferrule and the transparent member are made of the same material.   4. The laser module according to claim 1, wherein an end face of the ferrule, an incident end face of an optical fiber, and the transparent member are bonded at room temperature. 5.   4. The laser module according to claim 1, wherein an end face of the ferrule and the transparent member are joined by potting. 5.   6. The laser module according to claim 1, wherein the laser light source is a semiconductor laser that emits a laser beam having a wavelength in a range of 350 to 500 nm. A laser holder having a laser holding portion for holding the laser light source, and an optical system holder accommodating portion in which a sliding surface extending in the optical axis direction of the laser light source is formed;
The optical system holder further comprising an optical system holder that holds the condensing optical system and is housed in a portion of the optical system holder housing portion where the sliding surface is formed. A laser module according to claim 1. An apparatus for assembling the laser module according to claim 7,
Laser holder holding means for holding the laser holder;
An optical system holder holding means for holding the optical system holder in a state of being accommodated in an optical system holder housing portion of the laser holder;
A fiber end holding means that holds the ferrule accommodating and fixing the optical fiber and / or the transparent member bonded to the ferrule, and is movable by a minute amount in the axial direction of the optical fiber;
An alignment means capable of adjusting the laser holder holding means and the optical system holder holding means in a direction in which the optical axis of the condensing optical system coincides with the axial direction of the optical fiber;
An apparatus for assembling a laser module, comprising: a photodetector for detecting a light intensity of a laser beam emitted from an emission end face which is the other end face of the optical fiber. The aligning means has a part of a spherical surface and a concave part that is slidably and closely combined with a part of the spherical surface,
One of the spherical surface and one of the concave surface portions is placed between the other and the normal fiber is aligned in the axial direction of the optical fiber held by the fiber end holding means. Placed in a state facing each other,
9. The laser module assembling apparatus according to claim 8, wherein a part of the spherical surface and the other of the concave surface portion are connected to the laser holder holding means.

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