WO2003085435A1

WO2003085435A1 - Optical fiber aligning method, semiconductor laser module manufacturing method, and semiconductor laser module

Info

Publication number: WO2003085435A1
Application number: PCT/JP2002/009539
Authority: WO
Inventors: Masashi Nakae; Toshio Kimura
Original assignee: Furukawa Electric Co., Ltd
Priority date: 2002-04-04
Filing date: 2002-09-17
Publication date: 2003-10-16
Also published as: CN1623109A

Abstract

An optical fiber aligning method comprising a first step of aligning an optical fiber by moving the optical fiber by using a power meter so that the optical output power of the optical fiber is maximized, and a second step of aligning the optical fiber by moving the optical fiber in the optical axis direction (Z-direction) from a position aligned in the first step so that the degrees of polarization of two laser beams (K1 and K2) are below a predetermined value when measured by using a polarization degree meter.

Description

Specification

Optical fiber alignment method, semiconductor laser module manufacturing method, and semiconductor laser module

The present invention relates to a method for aligning an optical fiber, a method for manufacturing a semiconductor laser module, and a semiconductor laser module, and in particular, to adjusting an optical fiber that receives two laser lights after polarization synthesis. The present invention relates to a core method and a method for manufacturing a semiconductor laser module. Background art

With the recent development of optical communication using the high-density wavelength division multiplexing transmission method, there is an increasing demand for higher output power for pumping light sources used in optical amplifiers.

In recent years, expectations for Raman amplifiers as means for amplifying light in a wider band than erbium-doped optical amplifiers conventionally used as optical amplifiers are increasing. Raman amplification is caused by stimulated Raman scattering that occurs when excitation light is incident on an optical fiber, and a gain appears on the low frequency side of about 13 THz from the excitation light wavelength. This is a method for amplifying an optical signal utilizing the phenomenon that when signal light in the wavelength band having the above-mentioned gain is input to an optical fiber in a state where the signal light is gained, the signal light is amplified.

In Raman amplification, the signal light is amplified while the polarization directions of the signal light and the pump light (pump light) match, so the effect of the shift in the polarization direction between the signal light and the pump light is reduced. It must be as small as possible. Therefore, the polarization of the excitation light is eliminated (depolarization) to reduce the degree of polarization (D OP: Degree Of Polarization).

Conventional semiconductor laser module used as an excitation light source for optical amplifiers, etc. As a method of depolarizing the laser light from Yule, for example, a method is known in which two laser lights are polarization-combined and output from an optical fiber.

FIG. 11 is an explanatory diagram for explaining a conventional semiconductor laser device disclosed in US Pat. No. 5,589,684.

As shown in FIG. 11, the conventional semiconductor laser device includes a first semiconductor laser element 100 and a second semiconductor laser element 101 that emit laser beams at the same wavelength and in directions orthogonal to each other. A first collimator lens 102 for collimating the laser light emitted from the first semiconductor laser element 1002, and an emission light from the second semiconductor laser element 101. A second collimator lens 103 for collimating the laser beam, a first collimator lens 102 and a second collimator lens. A polarization combining laser 104 for orthogonally polarizing the laser beams collimated by 103 and a laser beam combining for polarization by the polarization combining bracket 104 The converging lens 105 and the laser beam condensed by the converging lens 105 Ino 107 and

According to the conventional semiconductor laser device, the first semiconductor laser element 1

Since the laser light emitted from the second semiconductor laser element 101 and the second semiconductor laser element 101 in the directions orthogonal to each other is polarized and combined by the polarization combining power plate 104, the optical fiber 107 Can emit a laser beam with a small degree of polarization (hereinafter referred to as Conventional Example 1).

Japanese Patent Application Laid-Open No. 60-76707 discloses that the first and second laser beams are arranged on a heat sink, the optical axis and the polarization direction are parallel to each other, and the emission end faces are almost coincident. First and second semiconductor laser elements that respectively emit light, and are arranged on the optical path of the first laser light emitted from the first semiconductor laser element, and rotate the polarization direction of the first laser light by 90 °. Then, the polarization rotator that makes the polarization direction of the second laser beam perpendicular to the first and second polarization rotators that make the polarization direction perpendicular to each other A polarizing element (calcite plate) that joins the optical paths of laser light by the birefringence effect, an optical filter that receives laser light from the polarizing element side and sends it out, and a laser light that is joined by the polarizing element into an optical fiber A semiconductor laser module having a lens having the following features is disclosed. In this semiconductor laser module, the first and second semiconductor laser elements are housed in a package to form a unit (hereinafter referred to as Conventional Example 2).

Also, Japanese Patent Application Laid-Open No. 2000-315575 discloses an electronic cooling element, first and second semiconductor laser elements mounted on the electronic cooling element, and an electronic cooling element mounted on the electronic cooling element. First and second collimator lenses for collimating the first and second laser beams emitted from the first and second semiconductor laser devices, respectively, and the first and second collimator lenses. There is disclosed a semiconductor laser module including a second polarization-combining element for polarization-combining the laser light and an optical fiber for receiving the laser light output from the polarization-combination element and transmitting the laser light to the outside. Further, the first and second semiconductor laser elements are configured as an LD array formed at a pitch of 500 m between emission centers. The first and second collimator lenses are configured as a lens array such as a spherical lens array or a Fresnel lens array (hereinafter referred to as Conventional Example 3).

However, in Conventional Example 1, since it is necessary to position each lens with respect to the laser light output from the semiconductor laser element, there is a problem that the manufacturing process is complicated and the manufacturing time is long.

In the conventional example 2, the laser beam from the semiconductor laser device is directly received by the polarization rotator or the polarization device. Therefore, conventionally, in order to obtain high optical coupling efficiency in the configuration of Example 2, it is necessary to design the distance between the semiconductor laser element and the lens to be about 300 to 500 μηι. It is very difficult to arrange a polarization rotation element and a polarization element between one semiconductor laser element and one lens. Enlarge the lens This can create space, but the package is several times larger than that currently used, and the problem is that the semiconductor laser module will become larger. There is.

In Conventional Example 3, two beams emitted at a wide interval (pitch between emission centers of 500 μm) are received by different lenses, respectively, so that two laser beams parallel to each other are obtained. Because of the configuration, the semiconductor laser device becomes large, and the amount of semiconductor chips obtained from one wafer is reduced, which is not suitable for mass production. If the stripe spacing of the semiconductor laser device is reduced to solve this problem, it is necessary to reduce the size of the lens, and it becomes difficult to separate the light emitted from each stripe. Subsequent polarization combining and optical combining become difficult.

In order to solve the above-mentioned problem, the applicant of the present invention has proposed a method in which a single semiconductor laser device having two stripe-shaped light-emitting portions (hereinafter simply referred to as “strips”) is used. We propose a semiconductor laser module that combines two laser beams with polarization and receives them with an optical fiber (for example, refer to Japanese Patent Application No. 2001-38840). Technology is referred to as related technology).

FIG. 5 is an explanatory diagram schematically showing a configuration of a semiconductor laser module according to the related art.

As shown in FIG. 5, a semiconductor laser module M 1 according to the related art has a first stripe 9 and a second stripe formed parallel to each other at an interval of about 100 μηι or less. A first laser beam K 1 and a second laser beam from the front end face 2 a (the right side in FIG. 5) of the first stripe 9 and the second stripe 10. A single semiconductor laser element 2 that emits light K 2, a first laser light K 1 and a second laser light K 2 emitted from the semiconductor laser element 2 are incident, and the first laser light K 1 A first lens 4 for separating the second laser beam K 2 from the first and second stripes 9 and 10 in a parallel direction; And a half wavelength that rotates the polarization direction of at least one of the first and second laser beams Kl and Κ2 (in the case of FIG. 5, the first laser beam K1) by a predetermined angle (for example, 90 degrees). A plate 6 (polarization rotating element), a polarization combining element 7 (hereinafter, referred to as a PBC (Polarization Beam Combiner)) that combines and emits the first laser light Κ1 and the second laser light Κ2. An optical fiber 8 optically couples with the combined light emitted from the PBC 7 and sends the combined light to the outside.

A prism in which a first laser beam K 1 and a second laser beam K 2 enter between the first lens 4 and the half-wave plate 6 and exit with their optical axes substantially parallel to each other. 5 are provided. In addition, between the PBC 7 and the optical fiber 8, the second laser light K 1 and K 2, which are polarization-combined by the PBC 7, are optically coupled to the optical fiber 8. Lens 16 is provided.

As PBC7, a birefringent element such as rutile crystal or YV04 is used.

First laser light K 1 and second laser light K 2 emitted from front end face 2 a of first stripe 9 and second stripe 10 of semiconductor laser element 2, respectively. After passing through the first lens 4 and intersecting, it is separated into wide spaces and sufficiently separated, and then enters the prism 5.

Due to the prism 5, the first laser light K1 and the second laser light K2 are emitted in parallel with each other at an interval D, and the first laser light K1 is transmitted to the half-wave plate 6. The incident light is rotated by 90 degrees in the polarization direction, is incident on the first input portion 7a of the PBC 7, and the second laser beam K2 is incident on the second input portion 7b of the PBC 7.

In the PBC 7, the first laser light K1 incident from the first input unit 7a and the second laser light K2 incident from the second input unit 7b are polarized and multiplexed and output. The light is emitted from the part 7c.

The laser light emitted from PBC 7 is passed through the second lens 16 The light is collected, incident on the end face of the optical fiber 8 held by the ferrule 23, and sent out.

According to the semiconductor laser module Ml according to the related art, one semiconductor laser element 2 is formed at a narrow interval of 100 m or less from the first and second stripes 9 and 10. The first laser light K 1 and the second laser light K 2 having the same polarization direction are emitted, and after being sufficiently separated by the first lens 4, the first laser light K 1 is separated by the half-wave plate 6. The polarization direction of 1 is rotated exactly 90 degrees. In this state, the first laser beam K 1 and the second laser beam K 2 are polarization-synthesized by the PBC 7, so that a laser beam having a high output and a small degree of polarization is output from the optical fiber 8. It can be emitted.

Therefore, the above-described semiconductor laser module Ml is used as an excitation light source for an erbium-doped optical amplifier that requires high output and a Raman amplifier that requires low polarization dependence and stability for amplification gain. Can be applied. '

Further, since one semiconductor laser element 2 having two stripes each of which emits laser light and a single first lens 4 for separating both laser lights Kl and Κ2 are used. However, the positioning time of the semiconductor laser element 2 and the first lens 4 is shortened. As a result, the manufacturing time of the semiconductor laser module # 1 can be reduced.

Furthermore, since two lights emitted from a single semiconductor laser element 2 propagate in the same direction, the semiconductor laser element 2, the first lens 4, the half-wave plate 6, the PBC 7, and the second lens 16 The effect of the warpage of the package that accommodates the optical components is limited to only one direction (the Z direction in FIG. 5), and the light output emitted from the optical fiber 8 can be stabilized.

Here, in the manufacturing method of the semiconductor laser module according to the related art, in the positioning step of the optical fiber 8, as shown in FIG. 12 (A), a power meter is provided at the base end of the optical fiber 8. 2 Connect 6 and The ferrule 23 that holds the optical fiber 8 so that the light output is maximized is aligned and fixed by moving the ferrule 23 in the X, ,, and Z-axis directions using the ferrule alignment hand 28. .

As described above, since a birefringent element such as rutile crystal or YVO 4 is used as the PBC 7, the first laser beam is used as shown in FIG. 12 (B). The physical lengths and refractive indices nl and n2 of the optical path through which the K1 and second laser beams K2 pass through the PBC 7 are different

(For example, the refractive index nl is 2.46 and the refractive index n2 is 2.71). For this reason, the respective focal points formed on the first laser beam K 1 and the second laser beam K 2 optically downstream of the second lens 16 (beam gap: Gaussian beam) The positions G 1 and G 2 of the portion having the smallest dot size (the portion where the laser beam is most concentrated) do not match as shown in FIG. 12 (B) (see FIG. 12 (B)). , Fl, F2 indicate the position of the beam west formed by the first lens 4, and Gl, G2 indicate the position of the beam west formed by the second lens 16.) In addition, there are differences in the amount of attenuation received by each laser beam before coupling to the optical fin 8, and differences in the radiation angle (FFP) and intensity of the laser beam emitted from each stripe. Due to these factors, the intensity of each laser beam coupled to the optical fiber 8 will be different.

As a result, when the optical fiber 8 is positioned in its axial direction (Z-axis direction) so that the optical output is maximized, there is a difference in the intensity of the light in the orthogonal state coupled to the optical fiber 8, so that the combined light is The degree of polarization (DOP) may not fall below the desired value.

Also, in the method of manufacturing a semiconductor laser module according to the conventional example, the characteristics (radiation angle (FFP: Far Field Pattern) of the laser from the emitting end face, optical output, wavelength, The degree of polarization may be increased due to individual differences in the temperature dependence of these components, differences in the arrangement of optical components, and warpage of the package. is there. Disclosure of the invention

The present invention has been made to solve the above-mentioned problem, and an optical fiber that optically couples with a synthetic light obtained by polarization-combining two laser lights is combined with an optical fiber. It is an object of the present invention to provide a method for aligning an optical fiber and a method for manufacturing a semiconductor laser module, wherein the optical fiber is aligned so that the degree of polarization of the light is not more than a predetermined value.

In the first method of aligning an optical fiber according to the present invention, at least two laser beams that have passed through one first lens are polarization-synthesized by a polarization-synthesizing element and then transmitted through the second lens. A method of aligning an optical fiber that optically couples with the combined light, wherein the optical fiber is moved so that the degree of polarization of the combined light that is optically coupled to the optical fiber is equal to or less than a predetermined value. It is characterized by alignment.

Further, the second method for aligning an optical fiber according to the present invention is characterized in that the two laser beams passing through at least one first lens are polarization-synthesized by a polarization-synthesizing element and then transmitted through the second lens. A method of aligning an optical fiber that optically couples with the combined light, wherein the optical fiber is moved so that the intensity of the combined light that optically couples with the optical fiber is maximized. A first step of centering and moving the optical fiber in the axial direction of the optical fiber so as to align the optical fiber so that the degree of polarization of the combined light optically coupled to the optical fiber is equal to or less than a predetermined value. It is characterized by having a second step.

Since the optical length of the optical path between the first and second lenses of the two laser beams passing through the polarization combining element is different, the beam paste of each of the two laser beams formed optically downstream of the second lens is They are located at different positions in the axial direction of the optical fiber. Therefore, if the optical fin is moved between them, the coupling efficiency between each laser light and the optical fin changes, and the intensity of each laser light coupled to the optical fiber is changed. Since it is possible to find a position where the values are equal, the degree of polarization of the combined light can be reduced.

The two laser beams may form a beam waste between the first lens and the second lens, respectively.

Since the beam waist is between the first and second lenses, the beam diameter between the first and second lenses is reduced, and the propagation length required for the separation width of the two laser beams to exceed a predetermined value is reduced. Since the length is shorter, the length up to the optical fiber can be shortened. Also, the optical components used between the first lens and the second lens can be reduced in size.

The two laser beams may be emitted from a single semiconductor laser device including two stripes each of which emits a laser beam.

The two stripes may be parallel to each other.

The two stripes may be separated by an interval of 100 m or less.

In the first or second optical fiber alignment method, at least one first lens may be a single lens that deflects and passes the two laser beams. Preferably, it may be configured as a lens array composed of two lenses passing each of the two laser beams.

A first method for manufacturing a semiconductor laser module according to the present invention is a method for manufacturing a semiconductor laser module, comprising: a single semiconductor laser element that emits laser light and has two stripes arranged at an interval; A single first lens that deflects and passes the two laser lights emitted from the loop, a polarization combining element that combines the two laser lights that have passed through the first lens, and the polarization A method for manufacturing a semiconductor laser module, comprising: a second lens for condensing combined light emitted from a combining element; and an optical fiber optically coupled to the combined light emitted from the second lens. A third step of fixing the semiconductor laser device on a base A fourth step of aligning the first lens and fixing the first lens on the base so that the two laser lights passing through the first lens are in predetermined directions, respectively; A fifth step of aligning and fixing the composite element, and a sixth step of aligning and fixing the optical fiber by the first or second optical fiber alignment method of the present invention. It is characterized by having.

According to this configuration, since the two laser beams pass through the polarization combining element, their optical paths have different optical lengths. In this state, the beam wests of the two laser beams formed optically downstream of the second lens are shifted from each other in the axial direction of the optical fiber. In such a situation, since the first or second optical fiber alignment method of the present invention is used, a semiconductor laser module having a small degree of polarization of output laser light can be manufactured.

In addition, a single semiconductor laser element having two stripes arranged at an interval and a single first lens that deflects and passes two laser beams emitted from it are used. In addition, a small laser module can be manufactured.

In the fourth step, the first lens is formed such that the two laser beams passing through the first lens form a beam gap between the first lens and the second lens, respectively. Alignment may be performed.

Since there is a beam waist between the first and second lenses, the beam diameter between the first and second lenses becomes smaller, and the propagation length required for the separation width of the two laser beams to exceed a predetermined value is reduced. Since the length becomes shorter, the length of the laser module can be shortened. Also, by using small optical components, the size of the module can be reduced.

The semiconductor laser module further has a prism that makes the optical axes of the two laser beams that have passed through the first lens parallel to each other and emits the polarized light toward the polarization combining element. A polarization combining element and the prism are held by a common holder, In the fourth step, the optical axes of the two laser beams passing through the first lens intersect with each other, and are substantially symmetric with respect to a center axis in the first lens. The first lens is aligned and fixed on the base so as to move toward the prism.

In the fifth step, the polarization combining element may be aligned and fixed by moving the holder member.

The two laser beams emitted from the first lens are separated and propagate symmetrically with respect to the center axis of the first lens, and these optical axes are made parallel to each other by the prism. Design and processing of the synthesis element are facilitated, and the alignment of the laser element with the lens, prism, and polarization synthesis element is facilitated. Also, since the polarization combining element is fixed to one holder together with the prism, the alignment of the prism and the polarization combining element becomes very easy.

The two stripes may be parallel to each other.

The two stripes may be separated by an interval of 100 μm or less.

According to a second method for manufacturing a semiconductor laser module of the present invention, there are provided two semiconductor laser elements each having a stripe for emitting one laser beam, and emission from each of the two stripes. Two first lenses that respectively transmit the laser light to be emitted, a polarization combining element that combines the two laser lights that have passed through the first lens, and a combined light that is emitted from the polarization combining element. A method of manufacturing a semiconductor laser module comprising: a second lens for condensing light; and an optical fiber that optically couples with synthetic light emitted from the second lens. A seventh step of fixing the element on the base, and aligning each of the two first lenses such that the two laser beams passing through the first lens are directed in predetermined directions, respectively. On the base An eighth step, a ninth step of fixing the polarization combining element the alignment to, the first or alignment method of the second optical fiber of the present invention And a 10th step of aligning and fixing the optical fiber.

In this configuration, light emitted from separate semiconductor laser elements

The two laser beams pass through separate first lenses, respectively.If the distance between the semiconductor laser element and the first lens is different due to manufacturing variations between the two laser beams, the second lens The position of the beam waste of each laser beam formed optically downstream of the optical fiber may differ in the axial direction of the optical fiber. Also, if the characteristics such as the radiation angle (FFP) from the emission end face of each semiconductor laser element are different, the coupling efficiency between each semiconductor laser element and the optical fiber is different. In such a situation, even though the two laser beams are polarized and combined, the degree of polarization does not become sufficiently small, but the second method for manufacturing a semiconductor laser module of the present invention does not Since the first or second optical fiber alignment method is used, by aligning the optical fiber between the beam wastes formed optically downstream of the second lens, the output laser beam can be adjusted. A semiconductor laser module having a small polarization degree of the light can be manufactured.

The semiconductor laser module further includes a reflector that reflects one of the two laser beams passing through the first lens toward one of the input units of the polarization combining element, and The element and the reflector are held by a common holder, and

In the seventh step, the two semiconductor laser elements are fixed so that the optical axes of the two laser beams emitted from the two stripes are parallel to each other.

In the ninth step, the polarization combining element may be aligned and fixed by moving the holder.

Since the polarization combining means is fixed to one holder together with the reflector, these alignments are extremely easy.

The two first lenses are configured as a lens array, and the seventh step is a method in which the two first lenses emitted from the two stripes are used. The two semiconductor laser elements may be fixed so that the optical axes of the laser beams are parallel to each other.

A third method for manufacturing a semiconductor laser module according to the present invention is a method for manufacturing a semiconductor laser module, comprising: a single semiconductor laser element that emits laser light and has two stripes arranged at an interval; Two first lenses that respectively pass laser light emitted from each of the lights; a polarization combining element that combines the two laser lights that have passed through the two first lenses; A method for manufacturing a semiconductor laser module, comprising: a second lens that collects combined light emitted from a wave combining element; and an optical fiber that optically couples with the combined light emitted from the second lens. And

A first step of fixing the semiconductor laser element on a base; and the two first steps so that the two laser beams passing through the two first lenses are directed in predetermined directions, respectively. A 12th step of aligning the lens and fixing it on the base; a 13th step of aligning the polarization combining element and fixing it on the base; Alternatively, there is provided a 14th step of aligning and fixing the optical fiber by a second method for aligning the optical fiber.

The two stripes may be parallel to each other, and the two first lenses may be configured as a lens array.

A first semiconductor laser module of the present invention has a first stripe and a second stripe formed with an interval therebetween, and the first stripe and the second stripe are formed. A single semiconductor laser element that emits a first laser light and a second laser light from one end face of the light, respectively, and the first and second stripes that are emitted from the first stripe and the second stripe. A single first lens that deflects and transmits the first laser light and the second laser light, and at least one polarization of the first and second laser lights emitted from the first lens A polarization rotator for rotating a direction, a first input unit into which the first laser light is incident, A second input section to which the second laser light is incident; a first laser light to be incident from the first input section; and a second laser light to be incident from the second input section. A polarization combining element having an output part from which and are combined and emitted, a base on which the semiconductor laser element and the first lens are mounted, and an emission part emitted from the output part of the polarization combining element. A second lens for condensing the combined light; an optical fiber positioned so as to receive laser light emitted from the second lens; and a semiconductor laser module having:

The optical fiber is fixed between the respective beam Wests of the laser beams formed optically downstream of the second lens.

The first and second stripes may be separated by an interval equal to or less than lOO ^ m.

A second semiconductor laser module according to the present invention has a first stripe and a second stripe formed with an interval therebetween, and the first stripe and the second stripe are formed. A single semiconductor laser element that emits a first laser light and a second laser light from one end face of the laser, respectively, and light emitted from the first stripe and the second stripe. Two first lenses for passing the first laser light and the second laser light, respectively, and rotating at least one polarization direction of the first and second laser lights passing through the first lens. A polarization rotator, a first input unit to which the first laser light is incident, a second input unit to which the second laser light is incident, and an incident light from the first input unit. A first laser beam and a second laser beam incident from the second input unit. A polarization combining element having an output section from which laser light is multiplexed and emitted, a base on which the semiconductor laser element, the two first lenses are mounted, and a polarization combining element. A second lens for condensing the laser light emitted from the output unit, an optical fiber positioned to receive the laser light emitted from the second lens, A semiconductor laser module having

The optical fiber is fixed between beam wests of respective laser beams formed optically downstream of the second lens.

A third semiconductor laser module according to the present invention includes two semiconductor laser elements each having one stripe for emitting laser light, and a first laser light emitted from the two semiconductor laser elements. And two first lenses that respectively pass the second laser light, and a polarization rotating element that rotates at least one polarization direction of the first and second laser lights that have passed through the two first lenses. A first input unit to which the first laser light is incident; a second input unit to which the second laser light is incident; and a first input unit to be incident from the first input unit. A polarization combining element having an output unit that combines and emits the laser light and the second laser light incident from the second input unit; and the first and second light-transmitting elements that have passed through the first lens. One of the second laser beams is used as the polarization A reflector that reflects toward one of the first input section and the second input section, the two semiconductor laser elements, a base on which the two first lenses are mounted, and a polarization combining element. A semiconductor laser module comprising: a second lens for condensing laser light emitted from the output unit; and an optical filter positioned to receive the laser light emitted from the second lens,

The optical fiber is characterized in that it is fixed between the beams of the respective laser beams formed optically downstream of the second lens.

The two first lenses may be configured as a lens array. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic view of a method according to a first embodiment of the present invention. 1 is a side sectional view showing a configuration of a semiconductor laser module to be manufactured. FIG. 2 is an explanatory diagram schematically showing a configuration for carrying out the method according to the present invention.

FIG. 3 is a graph showing changes in the optical output (relative value with the maximum value being 100) and the degree of polarization with respect to the movement amount of the optical fiber in the Z-axis direction according to the embodiment of the present invention.

FIG. 4 is a diagram illustrating the intensity of two laser beams coupled to the optical fiber and the intensity of the combined light when the optical fiber is moved in the Z-axis direction.

FIG. 5 is an explanatory diagram schematically showing the configuration of the semiconductor laser module according to the related art and the first embodiment of the present invention.

FIG. 6 (A) shows a polarization combining module, and FIG. 6 (B) is a cross-sectional plan view taken along the line A—A, FIG. 6 (B) is a side cross-sectional view, and FIG. 6 (C) is a front view.

FIG. 7 is an explanatory diagram for explaining the alignment process of the first lens. FIG. 8 is a perspective view for explaining a process of aligning and fixing the polarization combining module.

FIG. 9 is a plan view showing a semiconductor laser module according to the second embodiment of the present invention.

FIG. 10 is a plan view showing a semiconductor laser module according to the third embodiment of the present invention.

FIG. 12 is an explanatory diagram for explaining a problem in the optical fiber alignment method. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same parts as the components of the semiconductor laser module shown in Fig. 5 Materials will be described with the same reference numerals.

(First Embodiment)

FIG. 1 is a side sectional view showing a configuration of a semiconductor laser module manufactured by the method according to the first embodiment of the present invention.

As shown in FIG. 1, a semiconductor laser module M 1 manufactured by the method according to the embodiment of the present invention includes a package 1 hermetically sealed inside, and a package 1 provided inside the package 1. A semiconductor laser element 2 for emitting laser light, a photo diode (light receiving element) 3, a first lens 4, a prism 5, a half-wave plate (polarization rotating element) 6, a polarization It has a PBC 7 or the like serving as a combining element and an optical fiber 8.

As shown in FIG. 5, the semiconductor laser element 2 includes a first stripe 9 and a second stripe 10 formed in parallel with each other in the longitudinal direction at an interval. The first laser light K 1 and the second laser light K 2 are emitted from the front end face 2 a of the first stripe 9 and the second stripe 10, respectively. K 1 and K 2 shown in FIG. 5 indicate the trajectories of the centers of the beams emitted from the first stripe 9 and the second stripe 10, respectively. The beam propagates with a spread around this center, as indicated by the dashed line in Figure 5. The distance between the first stripe 9 and the second stripe 10 is set to 100 0 so that the light K l, Κ 2 emitted from each of the first stripe 9 and the second stripe 10 can enter one first lens 4. μπι or less, for example, about 40 to 60 μιη. Further, since the spacing between the stripes is narrow, the difference in the light output characteristics between the stripes is reduced.

As shown in FIG. 1, the semiconductor laser device 2 is fixedly mounted on the chip carrier 11 (or via a heat sink (not shown)).

The photodiode 3 receives the monitor laser beam emitted from the rear face (left side in FIG. 1) of the semiconductor laser element 2 and the end face 2b (see FIG. 5). Photo diode 3 is a photo diode carrier. Fixed to 1 2.

The first lens 4 is composed of a first laser beam K 1 and a second laser beam K 2 emitted in parallel from each other from an end face 2 a (see FIG. 5) of the front side (the right side in FIG. 1) of the semiconductor laser element 2. Are made to intersect with each other, the distance between them is widened and separated in the parallel direction of the stripes 9 and 10, and the laser beams Kl and K2 are separated by the first lens 4 and the first lens 4 described later. A beam waist is formed at different positions F1 and F2 between the two lenses 16 (see Fig. 5). Therefore, after exiting the first lens 4, the two laser beams K1 and K2 become non-parallel to each other.

As shown in FIG. 1, the first lens 4 is held by a first lens holding member 13. In order to suppress the influence of spherical aberration, it is preferable to use an aspherical lens having a small spherical aberration and a high coupling efficiency with the optical fiber 8 as the first lens 4.

The prism 5 is disposed between the first lens 4 and the PBC 7, corrects the optical paths of the first laser light K1 and the second laser light K2, and corrects the optical axes of each other. The light is emitted almost parallel (see Fig. 5). The prism 5 is made of an optical glass such as BK7 (crown silicate glass). Since the optical axes of the first and second laser beams Kl, Κ 2 propagating non-parallel from the first lens 4 are made parallel by the refraction of the prism 5, It will be easier to create the PBC 7 to be deployed.

As shown in FIG. 5, the half-wave plate 6 receives only the first laser beam Κ1 out of the first laser beam K1 and the second laser beam Κ2 passing through the prism 5. This is a polarization rotating element that rotates the polarization direction of the incident first laser beam 1 by 90 degrees. The first lens 4 sufficiently separates the first and second laser beams Kl and Κ2, so that the half-wave plate 6 can be easily arranged.

The PBC 7 includes a first input unit 7a to which the first laser light K1 is incident, a second input unit 7b to which the second laser light K2 is incident, and a second input unit 7b. The first laser beam Kl incident from the first input portion 7a and the second laser beam K2 incident from the second input portion 7b are multiplexed and outputted from the output portion 7 c and. The PBC 7 transmits, for example, the first laser beam K1 as an ordinary ray to the output section 7c, and converts the second laser beam K2 as an extraordinary ray to the output section 7c. This is a birefringent element that propagates to PBC 7 is made of, for example, Tio2 (rutile) in the case of a birefringent element.

In this embodiment, a polarization combining module 24 in which the prism 5, the half-wave plate 6, and the PBC 7 are fixed to the same holder member 14 is used. Fig. 6 (A) shows the polarization combining module 24, wherein (B) is a cross-sectional plan view taken along line A-A, (B) is a side cross-sectional view, and (C) is a front view thereof. As shown in FIG. 6, the holder member 14 of the polarization combining module 24 is made of a material suitable for YAG laser welding (for example, SUS403, 304, etc.), and its total length L2 is It is about 7.0 mm, and the whole is formed in a substantially columnar shape. A housing portion 14a is formed inside the holder member 14, and the prism 5, the half-wave plate 6, and the PBC 7 are fixed to the housing portion 14a, respectively. As shown in FIG. 8, the polarization combining module is centered and fixed via a second support member 19b having a substantially U-shaped cross section.

As a result, the first laser light K 1 incident from the first input section 7 & of the PBC 7 and the second laser light K 2 incident from the second input section 7 b are both output to the output section. It is very easy to adjust the position of the prism 5 and the PBC 7 around the central axis C1 so that the light is emitted from 7c.

In addition, if these optical components are integrated by the holder member 14 in this manner, the weight of the laser beam Kl, Κ2 at the output portion 7c between the laser beams Kl and Κ2 can be increased simply by moving the holder member 14. You can adjust the fit.

The optical fin 8 is a composite light emitted from the output 7c of the PBC 7. And sends it out of package 1.

Between the PBC 7 and the optical fin 8, a second lens 16 for optically coupling the laser light emitted from the output section 7c of the PBC 7 to the optical fiber 8 is provided. Preferably, the first lens 4 is configured to emit the first laser beam K 1 and the second laser beam K 2 between the first lens 4 and the second lens 16, Aligned to form F 2. As a result, the spot size of the laser beam between the first lens 4 and the second lens 16 is reduced, so that the half-wave plate 6 is inserted only on the optical path of the first laser beam K1. The propagation distance L (see FIG. 5) required to obtain a separation width D ′ between the first laser light K 1 and the second laser light K 2 that is sufficient to be obtained is reduced. For this reason, the length of the semiconductor laser module Ml in the optical axis direction can be shortened. As a result, for example, it is possible to provide a highly reliable semiconductor laser module M1 having excellent temporal stability of optical coupling between the semiconductor laser element 2 and the optical fiber 8 in a high-temperature environment.

In addition, since the beam diameter between the first lens 4 and the second lens 16 is small, a small optical component can be used, so that a small semiconductor laser module Ml can be designed.

As shown in FIG. 1, a chip carrier 11 to which a semiconductor laser element 2 is fixed and a photo diode carrier 12 to which a photo diode 3 is fixed have a first L-shaped cross section. It is fixed by soldering on the base 17 of the slab. The first base 17 is preferably made of a CuW-based alloy or the like in order to enhance the heat radiation of the semiconductor laser element 2 against heat.

The first lens holding member 13 to which the first lens 4 is fixed and the polarization combining module 24 to which the prism 5, the half-wave plate 6, and the PBC 7 are fixed to the holder member 14 are the first base. The first support member 19a and the second support, respectively, on a second stainless steel base 18 secured to the flat part 17a of the base 17 by silvering. Y via member 19b Fixed by AG laser welding.

A cooling device 20 composed of a Peltier element is provided below the first base 17. The temperature rise due to the heat generated by the semiconductor laser element 2 is detected by the thermistor 20a provided on the chip carrier 11, and the temperature detected by the thermistor 20a becomes constant. Thus, the cooling device 20 is controlled. As a result, the laser emission of the semiconductor laser element 2 can be increased in output and stabilized.

Inside the flange 1a formed on the side of the package 1, a window 1b into which light passing through the PBC 7 is incident, and a second lens 16 for condensing the laser light are provided. The second lens 16 is held by a second lens holding member 21 fixed to the end of the flange portion 1a by YAG laser welding, and is attached to the end of the second lens holding member 21. The ferrule 23 holding the optical fiber 8 is fixed by YAG laser welding via a metal sliding ring 22.

The operation of the semiconductor laser module M1 described above is described in the section of the prior art, and thus the description is omitted.

Next, a method for manufacturing the semiconductor laser module M1 described above will be described.

First, the chip carrier 11 to which the semiconductor laser element 2 is fixed and the photo diode carrier 12 to which the photo diode 3 is fixed are soldered on the first base 17. And fix it.

Next, the first lens 4 is aligned and fixed on the second base 18 which has been previously silver-silvered on the flat portion 17a of the first base 17. In the alignment process of the first lens 4, an electric current is supplied to the semiconductor laser element 2 so that the first laser light K 1 and the second laser light K 2 are supplied to the first laser light of the semiconductor laser element 2. Emitting light from both sides of the step 9 and the second stripe 10 and setting the emission direction as the reference direction, then insert the first lens 4 to set the X, Y, and Ζ axial directions. Position. FIG. 7 is an explanatory diagram for explaining a centering process of the first lens 4. Regarding the X-axis direction, as shown in FIG. 7 (A), the angle 0 1 between the reference direction (center axis C 2) set as described above and the first laser beam K 1, It is determined at a position where the angle 0 2 between the central axis C 2 and the second laser beam K 2 becomes equal. In the Y-axis direction, as shown in FIG. 7B, the first laser light K 1 and the second laser light K 2 are determined at positions passing through the center of the first lens 4. The Z-axis is determined at a specified distance from the semiconductor laser element 2 and at a position where the spot diameter of the laser beam is minimized. Preferably, the Z axis of the first lens 4 is set so that the spot diameter of the laser beam is minimized between the first lens 4 and the second lens 16 fixed in a later step. Position. The first lens holding member 13 that holds the first lens 4 at the position determined by the above alignment process is placed on the second base 18 via the first support member 19a. Fix by YAG laser welding.

Next, a polarization combining module 24 in which the prism 5, the half-wave plate 6, and the PBC 7 are integrated is aligned and fixed on the second base 18. In the alignment process of the polarization combining module 24, a dummy filter for positioning (a filter with a lens, not shown) receives the combined light from the output section 7c of the PBC 7. In the X, Y, and Z directions of the holder member 14, 0 (the angle around the Z axis), φ so that the light intensity coupled to the fiber is maximized. (Angle around Y axis), Ψ (Angle around X axis) Determine the position in the direction (see Fig. 8). At this time, the holder member 14 is fitted in the opening 19c between the two upright walls of the second support member 19b having a substantially U-shaped cross section as shown in FIG. , Z, θ, and Ψ, and by moving the second support member 19 b in the X-axis direction and the ごと direction.

At the position determined by the above centering process, as shown in FIG. 8, the second support member 19b is YAG-laser-welded to the second base 18 as shown in FIG. The solder member 14 is YAG laser-welded to the upright wall of the second support member 19b. In this way, the holder member 14 is fixed on the second base 18.

Next, the first base 17 is placed on a cooling device 20 previously fixed on the bottom plate of the package 1, and the laser beam emitted from the output portion 7 c of the PBC 7 is irradiated with the laser beam of the package 1. Align so that it passes through the center of the edge 1a, and fix it with solder.

Next, for the semiconductor laser device 2 and the monitor. The photo diode 3 is electrically connected to a lead (not shown) of the package 1 via a gold wire (not shown).

Next, a lid 1c is placed over the package 1 in an inert gas (eg, N ₂ , Xe) atmosphere, and the periphery is hermetically sealed by resistance welding.

Next, the second lens 16 is aligned and fixed to the flange portion 1a of the package 1 in the XY plane and the Z-axis direction. In this step, first, the second lens holding member 21 is moved on the end face of the flange portion 1a while being inserted into the sliding 1d, and the light emitted from the second lens 16 is moved to the knockout 1 At a position parallel to the central axis (parallel to the Z-axis) of the flange 1a, a sliding ring 1d is welded to the end of the flange 1a by YAG laser welding. Next, while monitoring the spread angle of the light emitted from the second lens 16, the second lens holding member 21 is moved, and this spread angle becomes equal to the light receiving angle (NA) of the optical fiber 8. The second lens holding member 21 and the slide ring 1d are fixed by YAG laser welding at the positions where they are approximately equal.

Finally, the optical fiber 8 is aligned and fixed. In performing this step, the optical fiber alignment method according to the present invention is used. FIG. 2 is an explanatory view schematically showing a configuration for carrying out a method according to the present invention, and FIG. 3 is a diagram illustrating a method for aligning an optical fiber according to an embodiment of the present invention. Light output (maximum 1 7 is a graph showing changes in relative value (0) and degree of polarization (DOP). In FIG. 3, P 1 indicates a position where the intensity of the combined light coupled to the optical fiber 8 is maximum, and P 2 indicates a position where the degree of polarization of the combined light coupled to the optical fiber 8 is minimum.

In this step, first, as shown in FIG. 2, a power meter 26 and a polarimeter (Polarimeter) 27 are connected to the end of the optical fiber 8 via a connector 25.

Next, with the ferrule 23 passed through the sliding ring 22, the ferrule 23 is gripped with the ferrule alignment hand 28, and in this state, the ferrule 23 is in a plane perpendicular to the optical axis of the optical fin 8 ( Adjust the position in the optical axis direction (Z direction) of the optical fiber and the optical fiber (Z direction) so that the optical output measured by the power meter 26 is maximized. Thus, the optical fiber 8 is moved to the position indicated by P1 in FIG.

Next, while measuring the degree of polarization of the combined light of the two laser beams Kl and Κ2 using the degree-of-polarization measuring device 27, the degree of polarization is minimized or less than a predetermined value (8% or less, preferably 5% or less). % Or less), the ferrule alignment hand 28 is moved in the Ζ-axis direction from the position where the alignment is performed in the above-described process, and the optical fiber 8 is aligned. As a result, the optical fin 8 is positioned at the position indicated by Ρ2 in FIG.

After the positioning of the optical fiber 8 is completed as described above, the ferrule 23 is fixed to the inside of the sliding ring 22 at that position by YAG laser welding. Next, the sliding 22 and the second lens holding member 21 are fixed by YAG laser welding at the boundary between the two. Thus, the work of aligning and fixing the optical fiber 8 is completed.

FIG. 4 is a diagram showing the intensity of two laser beams Kl and ， 2 coupled to the optical fiber 8 and the intensity of the combined light when the optical fiber 8 is moved in the axial direction (（-axis direction). . In FIG. 4, Gl and G2 denote the first and second laser beams Kl and Κ2, respectively, and the second lens 1 Figure 6 shows the position of the beam waste formed optically downstream of Fig. 6.

The displacement of the beam waste (Gl, G2) formed after the two laser beams Kl, K2 are emitted from the second lens (see Fig. 12 (B)) is caused by the birefringence element. This is generated based on the fact that the optical length (product of the refractive index and the physical length) determined by the physical length and the refractive index of the optical path of each laser beam passing through (PBC 7) is different. In addition to these differences, differences in the amount of attenuation applied to each laser beam before reaching the optical fiber 8, differences in the radiation angle (FFP) of each laser beam, and differences in each stop If there is a difference in the intensity of the laser light emitted from the laser, as shown in Fig. 4, an optical fiber in the Z-axis direction that gives the maximum value of the light intensity of each laser light coupled to the optical fiber 8 Not only does the position of bar 8 (which corresponds to the positions of beamwests Gl and G2 formed by each laser beam optically downstream of the second lens 16) shift, but also a difference appears in the maximum value. . In this state, the position where the intensity of the combined light coupled to the optical fiber 8 is maximum (P1 in FIG. 4) and the position where the degree of polarization is minimum (P2 in FIG. 4) are different. According to the measured data, as can be seen from FIG. 3, at the position (P 1) of the optical fiber where the maximum optical output is obtained, the degree of polarization of the combined light may increase to about 10%.

In the present embodiment, as described above, the optical fiber 8 is moved in its axial direction (Z-axis direction) so that the degree of polarization of the combined light polarized and synthesized by the birefringent element is minimized. Since it has a process of aligning the laser light, the optical length of the optical path of each laser light, the amount of attenuation received by each laser light, the emission angle of each laser light, or the laser light emitted from each stripe Even if there is a difference in the intensity, the optical fiber 8 can be fixed at a position where the degree of polarization is the smallest. Therefore, a semiconductor laser module that emits a laser beam with a small degree of polarization can be manufactured.

Also, after deciding the position of the optical fiber 8 at which the intensity of the combined light coupled to the optical fiber 8 is maximum, the optical fiber is set so as to minimize the degree of polarization. And it is generally 1 ≠ α2. When such two laser beams K l, Κ 2 are converged by the common second lens 16, a beam gap formed optically downstream of the second lens 16 is formed. The positions of Gl and G2 are shifted in the axial direction of the optical fin 8.

If the first semiconductor laser device 38 and the second semiconductor laser device 39 have different light outputs or radiation angles (FFP), the intensity of light coupled to the optical fin 8 is different.

For this reason, the degree of polarization of the combined light optically coupled to the optical fiber 8 may not be sufficiently low.

Therefore, in the second embodiment of the present invention, the optical fiber 8 is aligned so as to reduce the degree of polarization by the same method as that of the first embodiment, and thus the lens positional deviation is reduced. Even when there are variations such as individual differences among the semiconductor laser elements, a semiconductor laser module M 2 having a small degree of polarization of output light can be obtained.

Preferably, the cube beam splitter 42 and the mirror 43 and the half-wave plate 6 are fixed to the same holder having a substantially cylindrical outer periphery and a second support having a substantially U-shaped cross section. If it is fixed to the base 18 via the member 19b, the positioning work becomes easy.

Next, a method of manufacturing the semiconductor laser module M2 according to the second embodiment will be described.

First, two semiconductor laser elements 38 and 39 each having one stripe are placed on the first base 1 so that the optical axes of the laser beams emitted from the stripes are parallel to each other. 7, and then a photo diode 3 (not shown) is fixed at a position for receiving the laser beam emitted from the end face side.

Next, laser light is emitted from each of the two semiconductor laser elements 38 and 39, and the two first lenses 40 and 4 are emitted so that they become collimated light together. 1 are centered on the second base 18 made of stainless steel, which has been previously fixed with silver brazing on the first base 17. Then, it is fixed by YAG laser welding via a first support member 19a.

Next, a holder 14 (not shown) having a substantially cylindrical outer periphery holding the half-wave plate 6, the mirror 43, and the cube beam splitter (polarization combining element) 42 integrally, Alignment is performed via the second support member 19 b having a V-shape. In this alignment, a dummy fiber (not shown) (a fiber with a lens) is arranged at a position to receive the combined light emitted from the output part of the cube beam splitter 42. Hold the holder in the X, Y, and Z directions, Θ (angle around the Z axis) direction, and φ (angle around the Y axis) so that the intensity of the combined light coupled to the fiber is maximized. Align by moving in the direction and Ψ (angle around X axis) direction. After the centering of the cube beam splitter 42, the second support member 19b is welded at that position to the second base 18 by YAG laser welding, and then the holder 14 is attached to the second support member 1. Fix to 9 b.

Subsequent manufacturing steps including the alignment of the optical fiber 8 are the same as those in the first embodiment, and a description thereof will be omitted.

(Third embodiment example)

The semiconductor laser module M 3 according to the third embodiment includes a first stripe 44 and a second stripe formed in parallel with an interval of about 500 μπι. A semiconductor laser element 46, which is an array laser provided with a laser beam 45, a first lens 44, which receives a first laser beam K1 emitted from a first stripe 44, And a first lens 48 for receiving a second laser beam Κ 2 emitted from the first drive 45. Other configurations are the same as those of the first embodiment.

Also in the third embodiment, as in the first embodiment, the first laser beam K 1 and the second laser beam K 1 are used because C 7 is used. In addition to the difference in the optical length of the second optical path, the distance α 1 between the first stripe 44 and the first lens 47 and the distance between the second stripe 45 and the first lens 48 The fiber 2 differs due to manufacturing variations and the like. As a result, the beamwests Gl, G2 of the laser beams K1, Κ2 converged by the second lens 16 are shifted in the axial direction of the optical fiber 8.

In the third embodiment, the optical fiber 8 is aligned and fixed so that an end face exists between the beam wastes Gl and G2, so that a semiconductor having a small degree of polarization is provided. More preferably, the laser module M3 can be provided. As in the first embodiment, at least the PBC 7 and the half-wave plate 6 are fixed to one holder having a substantially cylindrical outer periphery and have a cross section. It may be fixed to the base 18 via a substantially U-shaped second support member 19b. This facilitates alignment and fixing of the PBC 7, the half-wave plate 6, and the like.

In this embodiment, the semiconductor laser device is an array laser having two stripes (the stripe interval is about 500πι). The elements may be arranged in parallel at narrow intervals. Further, the first lens may be a lens array arranged at the same interval as the two stripes.

Next, a method of manufacturing the semiconductor laser module # 3 of the third embodiment will be described.

First, a semiconductor laser element 46 having two stripes 44 and 45 is fixed on a first base 17, and then a laser beam (not shown) is placed at a position for receiving laser light emitted from the end face side. Fix photo diode 3.

Next, laser beams are emitted from the two strips 44 and 45, respectively, and two first lenses configured as lens arrays so that they become collimated light together. 4 7 and 4 8 are aligned, and a stainless steel stainless steel pre-fixed on the first base 17 with a silver opening is used. Since the alignment is performed by moving the optical fiber 8, the amount of movement of the optical fiber 8 in a series of alignment operations can be reduced, and the alignment can be performed efficiently.

In the semiconductor laser device of the present embodiment, since the two stripes are formed with a distance of 100 μm or less, the characteristics of both stripes can be made extremely close. The difference in the intensity of the laser light emitted from each stripe is small. For this reason, when the optical fiber is moved from the position where the intensity of the combined light becomes the maximum to the position where the polarization degree becomes the minimum, the decrease in the light intensity is small.

(Second embodiment example)

FIG. 9 is a plan view showing a semiconductor laser module according to the second embodiment of the present invention. As shown in FIG. 9, the semiconductor laser module M 2 according to the second embodiment of the present invention includes a first semiconductor laser element 38 that emits a first laser beam K 1, and a second laser beam The second semiconductor laser element 39 emitting K 2 and the two first laser beams K 1 and K 2 emitted from the two semiconductor laser elements 38 and 39 are respectively incident thereon. It has lenses 40, 41, a cube beam splitter 42, which is a polarization combining element, and a mirror 43, which is a reflector for reflecting the laser beam K 2 to the side of the cup beam splitter 42. . Other configurations are the same as those of the first embodiment.

In the second embodiment of the present invention, since the second laser beam K 2 enters the cube beam splitter 42 via the mirror 43, the first laser beam K 1 and the second laser beam K 2 The optical length of the optical path is different from that of the laser beam K 2. The distance << 1 between the first semiconductor laser element 38 and the first lens 40 and the distance _α2 between the second semiconductor laser element 39 and the first lens 41 are both the first 1 The lens 40, 41 is adjusted so that the emitted light becomes collimated light (the spread angle is ₀ °), but in reality, each laser light K l and Κ 2 are

26 It is fixed on the second base 18 by YAG laser welding via the first support member 19a.

Next, a holder 14 (not shown) having a cylindrical outer periphery holding the half-wave plate 6 and the PBC 7 in one piece is adjusted via a second support member 19 b having a substantially U-shaped cross section. Core. In this alignment, a dummy fiber (not shown) (lens-equipped fiber) is arranged at a position to receive the combined light emitted from the output portion of the PBC 7, and the fiber is provided. The holder is moved in the X, Y, and .Z directions, the θ (angle around the 、 axis) direction, the φ (angle around the Υ axis) direction, and Adjust by moving in the Ψ (angle around the X axis) direction. After the PBC 7 has been aligned, the second support member 19b is YAG laser-welded to the second base 18 at that position, and then the holder 14 is fixed to the second support member 19b. I do.

Subsequent manufacturing steps including the step of aligning the optical fiber 8 are the same as those in the first embodiment, and thus description thereof will be omitted.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the technical matters described in the claims. Industrial applicability

According to the present invention, since the optical fibers are moved and aligned so that the degrees of polarization of the two laser beams are equal to or less than a predetermined value, a semiconductor laser module having a low degree of polarization can be manufactured. You. Therefore, the semiconductor laser module manufactured by the method of the embodiment of the present invention is applied as a pump light source of a Raman amplifier that requires low polarization dependence and stability in amplification gain. be able to.

Claims

The scope of the claims

1.

At least two laser beams that have passed through one first lens are polarization-synthesized by a polarization-synthesizing element, and then optically aligned with the combined light via a second lens. The method

The optical fiber is characterized in that the optical fiber is moved and aligned so that the degree of polarization of the combined light optically coupled to the optical fiber is equal to or less than a predetermined value. Core method.

2.

A first step of moving and aligning the optical fiber so that the intensity of the combined light optically coupled to the optical fiber is maximized; and

A second step of centering the optical fiber by moving the optical fiber in the axial direction of the optical fiber so that the degree of polarization of the combined light optically coupled to the optical fiber is equal to or less than a predetermined value. ,

An alignment method for an optical fiber, comprising:

3.

3. The optical fiber alignment method according to claim 1, wherein the two laser beams form a beam waste between the first lens and the second lens. 4.

Four .

4. The laser device according to claim 1, wherein the two laser beams are emitted from a single semiconductor laser device including two stripes each emitting a laser beam. 5. Or in one section 光 Optical fiber alignment method

Five .

The optical fiber alignment method according to claim 4, wherein the two stripes are parallel to each other.

6.

The optical fiber alignment method according to claim 5, wherein the two stripes are separated by an interval of 100 µm or less.

7.

7. The apparatus according to claim 1, wherein the at least one first lens is a single lens that allows the two laser beams to pass while being deflected. 8. Optical fiber alignment method.

8.

The lens system according to claim 1, wherein the at least one first lens is configured as a lens array including two lens powers for passing each of the two laser beams. 6. The method for aligning an optical fiber according to any one of items 6 to 6.

9.

A single semiconductor laser device, each of which emits laser light and has two stripes arranged side by side,

A single first lens that deflects and passes the two laser beams emitted from the two stripes,

A polarization combining element that combines the two laser lights that have passed through the first lens with each other;

A second lens for condensing the combined light emitted from the polarization combining element And

A method for manufacturing a semiconductor laser module, comprising: an optical fiber that optically couples with combined light emitted from the second lens.

A third step of fixing the semiconductor laser element on a base; and aligning the first lens such that the two laser beams passing through the first lens are in predetermined directions. A fourth step of fixing on the base by

A fifth step of aligning and fixing the polarization combining element,

A sixth step of aligning and fixing the optical fiber according to the method according to claim 1 or 2,

A method for manufacturing a semiconductor laser module, characterized by having:

Ten .

The fourth step is such that the two laser beams passing through the first lens form a beam gap between the first lens and the second lens, respectively. The method for manufacturing a semiconductor laser module according to claim 9, wherein one lens is aligned.

The semiconductor laser module further has a prism that makes the optical axes of the two laser lights passing through the first lens parallel to each other and emits the light toward the polarization combining element. The polarization combining element and the prism are held by a common holder, and in the fourth step, optical axes of the two laser lights passing through the first lens cross each other. The first lens is centered and fixed on the base so as to face the prism in a state of being substantially symmetric with respect to the center axis of the first lens. Yes,

The fifth step is to move the holder member. The polarization combining element is aligned and fixed.

The method for manufacturing a semiconductor laser module according to claim 9 or 10, characterized by this.

1 2.

The method for manufacturing a semiconductor laser module according to claim 9, wherein the two stripes are parallel to each other.

13 .

The method for manufacturing a semiconductor laser module according to any one of claims 9 to 12, wherein the two stripes are separated by an interval of 100 m or less.

14 .

Two semiconductor laser elements each having a stripe for emitting one laser beam,

Two first lenses that respectively pass the laser beams emitted from each of the two stripes,

A polarization combining element that combines the two laser lights that have passed through the first lens, and

A second lens for condensing the combined light emitted from the polarization combining element,

A method of manufacturing a semiconductor laser module, comprising: an optical filter that optically couples with synthetic light emitted from the second lens.

A seventh step of fixing the two semiconductor laser elements on a base;

Each of the two first lenses is aligned so that the two laser beams passing through the first lens are directed in predetermined directions. An eighth step of fixing on the base,

A ninth step of aligning and fixing the polarization combining element,

A 10th step of aligning and fixing the optical fiber according to the method according to claim 1 or 2;

A method for manufacturing a semiconductor laser module, comprising:

1 5.

The semiconductor laser module further includes a reflector that reflects one of the two laser beams that have passed through the first lens toward one of the input units of the polarization combining element, and The polarization combining element and the reflector are held by a common holder,

In the seventh step, the two semiconductor laser elements are fixed so that the optical axes of the two laser beams emitted from the two stripes are parallel to each other. ,

The ninth step is to align and fix the polarization combining element by moving the holder.

15. The method for manufacturing a semiconductor laser module according to claim 14, wherein:

1 6.

The two first lenses are configured as a lens array, and the seventh step is to irradiate the two semiconductor laser elements with the optical axes of two laser beams emitted from the two stripes. Are fixed so that they are parallel to each other.

The method for manufacturing a semiconductor laser module according to claim 14, wherein:

1 7. A single semiconductor laser device, each of which emits laser light and has two stripes arranged side by side,

Two first lenses for passing the laser light emitted from each of the two stripes, respectively;

A polarization combining element that combines the two laser lights that have passed through the two first lenses,

A method of manufacturing a semiconductor laser module, comprising: an optical fiber that optically couples with synthetic light emitted from the second lens.

A first step of fixing the semiconductor laser element on a base; and the two first steps so that the two laser lights passing through the two first lenses are directed in predetermined directions, respectively. A first and second step of aligning the lens and fixing it on the base;

A thirteenth step of aligning the polarization combining element and fixing it on the base;

A fifteenth step of aligning and fixing the optical fiber according to the method of claim 1 or 2;

A method for manufacturing a semiconductor laser module, comprising:

1 8

The two stripes are parallel to each other and

18. The method for manufacturing a semiconductor laser module according to claim 17, wherein the two first lenses are configured as a lens array.

1 9.

First and second stripes formed through an interval A single semiconductor laser element having a first laser beam and emitting a first laser beam and a second laser beam from one end surfaces of the first stripe and the second stripe, respectively;

A single first lens that deflects and passes the first laser light and the second laser light emitted from the first stripe and the second stripe, and

A polarization rotation element for rotating at least one polarization direction of the first and second laser beams emitted from the first lens;

A first input unit to which the first laser light is incident, a second input unit to which the second laser light is incident, and a first laser light to be incident from the first input unit A polarization combining element comprising: a second laser beam incident from the second input unit; and an output unit from which the second laser beam is output.

A base on which the semiconductor laser element, the first lens is mounted, and a second lens for condensing the combined light emitted from the output section of the polarization combining element;

An optical fiber positioned to receive laser light emitted from the second lens;

A semiconductor laser module having

The semiconductor laser module according to claim 1, wherein the optical fiber is fixed between respective laser beam beamwests formed optically downstream of the second lens.

2 0.

The semiconductor laser module according to claim 19, wherein the first and second stripes are separated by an interval of 100 m or less.

twenty one It has a first stripe and a second stripe formed with an interval therebetween, and each has a first stripe and a second stripe from one end face of the first stripe and the second stripe. A single semiconductor laser element for emitting the first laser light and the second laser light,

Two first lenses for passing the first laser light and the second laser light emitted from the first stripe and the second stripe, respectively,

A polarization rotator that rotates at least one of the polarization directions of the first and second laser beams that have passed through the first lens;

A first input unit to which the first laser light is incident; a second input unit to which the second laser light is incident; and a first laser light to be incident from the first input unit And a second laser beam incident from the second input unit and an output unit from which the second laser light is output.

A base on which the semiconductor laser element and the two first lenses are mounted; and

A second lens for collecting laser light emitted from the output section of the polarization combining element;

An optical fiber positioned to receive a laser beam emitted from the second lens;

A semiconductor laser module having

The semiconductor laser module, wherein the optical fiber is fixed between respective laser beam beamwests formed optically downstream of the second lens.

twenty two .

Two semiconductor laser elements each having one stripe emitting laser light,

The first laser light emitted from the two semiconductor laser elements And two first lenses that respectively pass the second laser light, and a polarization rotator that rotates at least one polarization direction of at least one of the first and second laser lights that have passed through the two first lenses. ,

A first input unit on which the first laser light emitted from the first lens is incident, a second input unit on which the second laser light is incident, and the first input unit A polarization combining element having: an output section in which a first laser beam incident from the second laser beam and a second laser beam incident from the second input section are multiplexed and output;

A reflector for reflecting one of the first and second laser beams passing through the first lens toward one of a first input portion and a second input portion of the polarization combining element;

A base on which the two semiconductor laser elements are mounted, and a base on which the two first lenses are mounted;

A second lens that collects laser light emitted from the output unit of the polarization combining element;

An optical fiber positioned to receive laser light emitted from the second lens,

A semiconductor laser module having

A semiconductor laser module, wherein the optical fiber is fixed between beam waists of respective laser beams formed optically downstream of the second lens.

twenty three .

22. The semiconductor laser module according to claim 21, wherein the two first lenses are configured as a lens array.