JP5399194B2 - Laser equipment - Google Patents

Description

  The present invention relates to a laser apparatus.

  Laser light sources that output laser light having a plurality of wavelengths are used in various fields such as multi-wavelength interferometers, environmental monitors, laser radar, spectrum analysis, and terahertz wave generation. Such laser light sources are disclosed in, for example, Patent Documents 1 and 2.

  The laser light source disclosed in Patent Document 1 is a semiconductor laser diode in which a distributed feedback type resonator is formed, and the distributed feedback type resonator has a plurality of types of periodic structures. It is possible to oscillate laser light having a wavelength corresponding to the above.

  The laser light source disclosed in Patent Document 2 includes a semiconductor laser diode and an external resonator mirror to form an external resonator, and the external resonator mirror is formed on a planar substrate with a plurality of different types of reflections. A laser beam having a wavelength corresponding to the period of each diffraction grating can be laser-oscillated.

JP 63-70473 A Japanese Patent Laid-Open No. 3-148891

  The laser light source disclosed in Patent Document 1 can output laser light with a plurality of wavelengths, each oscillation wavelength is fixed, and the oscillation intensity ratio of the laser light with each wavelength is also fixed. In the laser light source disclosed in Patent Document 2, when the orientation of the external resonator mirror in which a plurality of types of reflective diffraction gratings are formed is adjusted with respect to the semiconductor laser diode, each oscillation wavelength changes. None of the laser light sources disclosed in the cited references 1 and 2 cannot change the oscillation intensity ratio of laser light of each wavelength while fixing each oscillation wavelength.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a laser device capable of changing the oscillation intensity ratio of laser light of each wavelength while fixing each oscillation wavelength. .

The laser device according to the present invention includes (1) an active layer extending between a first end face and a second end face facing each other, and resonates light having a wavelength λ ₀ included in a light emission spectrum in the active layer. A semiconductor laser diode in which a distributed feedback resonator is formed; and (2) light having a wavelength λ ₁ that is included in the light emission spectrum and is different from the wavelength λ ₀ among the light output from the first end face of the semiconductor laser diode. At least a portion is the Bragg reflection and a first wavelength selective element for feeding back to the active layer at least a portion of its Bragg reflected thereby the wavelength lambda ₁ of the light, (3) a first wavelength selected for the semiconductor laser diode First azimuth adjusting means for adjusting the relative azimuth of the element to adjust the amount of light of wavelength λ ₁ fed back from the first wavelength selection element to the active layer of the semiconductor laser diode.

In this laser device, a distributed feedback type resonator that resonates light having a wavelength λ ₀ included in the light emission spectrum in the active layer is formed in the semiconductor laser diode. In the first wavelength selection element, at least a part of the light having a wavelength λ ₁ different from the wavelength λ ₀ included in the light emission spectrum in the active layer of the semiconductor laser diode is Bragg-reflected, and the Bragg-reflected light having the wavelength λ ₁ is reflected. At least a part of them is returned to the active layer. An external resonator is configured by the semiconductor laser diode and the first wavelength selection element. Further, by adjusting the relative orientation of the first wavelength selection element with respect to the semiconductor laser diode, the amount of light having the wavelength λ ₁ fed back from the first wavelength selection element to the active layer of the semiconductor laser diode is adjusted. . This laser device can oscillate at wavelengths λ ₀ and λ ₁ , and the oscillation intensity of the laser light of each wavelength can be fixed while adjusting the inclination angle of the first wavelength selection element. The ratio can be changed.

(4) Of the light output from the first end face of the semiconductor laser diode, the laser device according to the present invention includes at least light having a wavelength λ ₂ included in the light emission spectrum and different from both the wavelength λ ₀ and the wavelength λ _1. some were Bragg reflector and a second wavelength selective element for feeding back at least a portion of its Bragg reflected thereby wavelength lambda ₂ of light in the active layer, (5) with respect to the semiconductor laser diode of the second wavelength selection element It is preferable to further include second azimuth adjusting means for adjusting the relative azimuth to adjust the amount of light of wavelength λ ₂ fed back from the second wavelength selection element to the active layer of the semiconductor laser diode. In this case, the laser device can oscillate at the wavelengths λ ₀ , λ ₁ , and λ ₂ , and adjust the tilt angles of the first wavelength selection element and the second wavelength selection element. The oscillation intensity ratio of the laser light of each wavelength can be changed while fixing each oscillation wavelength.

  The laser device according to the present invention is provided between the semiconductor laser diode and the first wavelength selection element, and collimates light output from the first end face of the semiconductor laser diode in a direction perpendicular to the active layer. It is preferable to further include a collimator lens that outputs to the first wavelength selection element. The laser apparatus according to the present invention is provided between the collimator lens and the first wavelength selection element, and rotates the transverse section of the light output from the collimator lens by approximately 90 degrees and outputs it to the first wavelength selection element. It is preferable to further include an element. In the laser device according to the present invention, it is preferable that the semiconductor laser diode includes a plurality of active layers arranged in parallel on a predetermined plane.

  The laser light source according to the present invention can change the oscillation intensity ratio of laser light of each wavelength while fixing each oscillation wavelength.

It is a figure which shows the structure of the laser light source 1 which concerns on 1st Embodiment. FIG. 3 is a diagram illustrating an example of a first wavelength selection element 121. It is a figure which shows the spectrum of output light when the inclination-angle of the 1st wavelength selection element 121 is set to (alpha) 1 in the laser light source 1 which concerns on 1st Embodiment. It is a figure which shows the spectrum of output light when the inclination-angle of the 1st wavelength selection element 121 is set to (alpha) 2 in the laser light source 1 which concerns on 1st Embodiment. It is a figure which shows the spectrum of output light when the inclination-angle of the 1st wavelength selection element 121 is set to (alpha) 3 in the laser light source 1 which concerns on 1st Embodiment. It is a figure which shows the spectrum of output light when the inclination-angle of the 1st wavelength selection element 121 is set to (alpha) 4 in the laser light source 1 which concerns on 1st Embodiment. It is a figure which shows the structure of the laser light source 2 which concerns on 2nd Embodiment. It is a figure which shows the structure of the laser light source 3 which concerns on 3rd Embodiment. It is a figure which shows the structure of the laser light source 4 which concerns on 4th Embodiment. It is a figure which shows the structure of the laser light source 5 which concerns on 5th Embodiment. It is a figure which shows the 1st end surface 111 of the semiconductor laser diode 110 contained in the laser light source 5 which concerns on 5th Embodiment. It is a figure which shows the structure of the laser light source 6 which concerns on 6th Embodiment. It is a figure which shows the structure of the laser light source 7 which concerns on 7th Embodiment. It is a perspective view which shows the optical path conversion element 140 contained in the laser light source 7 which concerns on 7th Embodiment. It is a figure which shows the structure of the laser light source 8 which concerns on 8th Embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant description is omitted. For convenience of explanation, each figure shows an xyz orthogonal coordinate system.

  (First embodiment)

  FIG. 1 is a diagram showing a configuration of a laser light source 1 according to the first embodiment. The laser light source 1 shown in this figure includes a semiconductor laser diode 100, a first wavelength selection element 121, and a collimator lens 130.

The semiconductor laser diode 100 has an active layer 103 extending in the z direction between a first end face 101 and a second end face 102 facing each other. The active layer 103 is layered, and has a width in the y direction of 100 μm to 200 μm and a thickness in the x direction of 1 μm, for example. The semiconductor laser diode 100 is of a so-called DFB (Distributed Feedback) type, in which a distributed feedback type resonator that resonates light having a wavelength λ ₀ included in the light emission spectrum in the active layer 103 is formed. The first end face 101 facing the first wavelength selection element 121 is coated with a reflection reducing film.

The first wavelength selection element 121 generates at least a part of light output from the first end face 101 of the semiconductor laser diode 100 and having a wavelength λ ₁ different from the wavelength λ ₀ included in the light emission spectrum of the active layer 103. Bragg reflection is performed, and at least a part of the light having the wavelength λ ₁ reflected by the Bragg reflection is returned to the active layer 103. The first wavelength selection element 121 transmits a part of the incident light and uses the transmitted light as output light from the laser light source 1. Specifically, as shown in FIG. 2, the first wavelength selection element 121 has a refractive index periodically distributed in the thickness direction (substantially z direction). The part can be Bragg reflected. As such a first wavelength selection element 121, for example, a product LuxxMaster ^™ manufactured by PD-LD Inc. is known.

The relative orientation of the first wavelength selection element 121 with respect to the semiconductor laser diode 100 is variable. By adjusting the orientation of the first wavelength selective device 121, it is possible to adjust the amount of wavelength lambda ₁ of the light fed back from the first wavelength selective device 121 into the active layer 103 of the semiconductor laser diode 100. The laser light source 1 includes first azimuth adjusting means for adjusting the azimuth of the first wavelength selection element 121 as described above.

  The collimator lens 130 is provided between the semiconductor laser diode 100 and the first wavelength selection element 121. The collimator lens 130 collimates the light output from the first end face 101 of the semiconductor laser diode 100 in the x direction perpendicular to the active layer 103 and outputs the collimated lens 130 to the first wavelength selection element 121. In general, the divergence angle of the light output from the first end face 101 of the semiconductor laser diode 100 is about 8 degrees in the y direction (Slow Axis direction) parallel to the layer of the active layer 103, whereas it is active. The x direction (Fast Axis direction) perpendicular to the layer 103 is as large as about 30 degrees. Therefore, the collimator lens 130 collimates the light output from the first end face 101 of the semiconductor laser diode 100 in the x direction (Fast Axis direction) perpendicular to the layer of the active layer 103.

A specific example of the laser light source 1 is as follows. The resonant wavelength λ ₀ of the distributed feedback resonator in the semiconductor laser diode 100 is 969 nm, and the central wavelength λ ₁ of Bragg reflection in the first wavelength selection element 121 is 976 nm. In this case, the laser light source 1 can perform laser oscillation at two wavelengths of a wavelength λ ₀ (969 nm) and a wavelength λ ₁ (976 nm). The first wavelength selection element 121 is inclined with a straight line parallel to the y direction as an axis, and the inclination angles of the first wavelength selection element 121 with respect to the xy plane are α1 to α4. However, α1 <α2 <α3 <α4.

  FIG. 3 is a diagram illustrating a spectrum of output light when the inclination angle of the first wavelength selection element 121 is α1 in the laser light source 1 according to the first embodiment. FIG. 4 is a diagram illustrating a spectrum of output light when the inclination angle of the first wavelength selection element 121 is α2 in the laser light source 1 according to the first embodiment. FIG. 5 is a diagram showing a spectrum of output light when the inclination angle of the first wavelength selection element 121 is α3 in the laser light source 1 according to the first embodiment. FIG. 6 is a diagram showing a spectrum of output light when the inclination angle of the first wavelength selection element 121 is α4 in the laser light source 1 according to the first embodiment.

In the case of the inclination angle α1 (FIG. 3), the output intensity at the wavelength λ ₁ (976 nm) is larger than the output intensity at the wavelength λ ₀ (969 nm). In the case of the inclination angle α2 larger than the inclination angle α1 (FIG. 4), the output intensity at the wavelength λ ₀ (969 nm) and the output intensity at the wavelength λ ₁ (976 nm) are approximately the same. In the case of the inclination angle α3 larger than the inclination angle α2 (FIG. 5), the output intensity at the wavelength λ ₁ (976 nm) is smaller than the output intensity at the wavelength λ ₀ (969 nm). Further, in the case of the inclination angle α4 larger than the inclination angle α3 (FIG. 6) as compared with the case of the inclination angle α3 (FIG. 5), the wavelength λ ₁ (976 nm) with respect to the output intensity of the wavelength λ ₀ (969 nm). The output intensity ratio is even smaller.

As can be seen from these drawings, the laser light source 1 according to the first embodiment can oscillate at two wavelengths of the wavelength λ ₀ and the wavelength λ ₁ and adjust the tilt angle of the first wavelength selection element 121. By doing so, it is possible to change the oscillation intensity ratio of the laser light having two wavelengths while fixing each oscillation wavelength. The laser light source 1 according to the first embodiment can be used in various fields such as a multi-wavelength interferometer, an environment monitor, a laser radar, spectrum analysis, and terahertz wave generation.

  (Second Embodiment)

  FIG. 7 is a diagram showing a configuration of the laser light source 2 according to the second embodiment. The laser light source 2 shown in this figure includes a semiconductor laser diode 100, a first wavelength selection element 121, a second wavelength selection element 122, and a collimator lens 130.

  The semiconductor laser diode 100, the first wavelength selection element 121, and the collimator lens 130 in the second embodiment are the same as those in the first embodiment. The collimator lens 130 is provided between the semiconductor laser diode 100 and the first wavelength selection element 121 and the second wavelength selection element 122. The collimator lens 130 collimates the light output from the first end face 101 of the semiconductor laser diode 100 in the x direction (Fast Axis direction) perpendicular to the layer of the active layer 103, and the collimated light is the first wavelength selection element. 121 and the second wavelength selection element 122.

The second wavelength selection element 122 is substantially the same as the first wavelength selection element 121, and is included in the light emission spectrum in the active layer 103 among the light output from the first end face 101 of the semiconductor laser diode 100. At least a part of light having a wavelength λ ₂ different from both the wavelength λ ₀ and the wavelength λ ₁ is Bragg reflected, and at least a part of the Bragg reflected light having a wavelength λ ₂ is fed back to the active layer 103. The second wavelength selection element 122 transmits a part of the incident light and uses the transmitted light as output light from the laser light source 2. Specifically, as shown in FIG. 2, the second wavelength selection element 122 also has a refractive index periodically distributed in the thickness direction (substantially z direction). The part can be Bragg reflected. The relationship between the three wavelengths λ ₀ , λ ₁ and λ ₂ is preferably λ ₁ <λ ₀ <λ ₂ or λ ₂ <λ ₀ <λ ₁ .

Just as the relative orientation of the first wavelength selection element 121 is variable with respect to the semiconductor laser diode 100, the relative orientation of the second wavelength selection element 122 with respect to the semiconductor laser diode 100 is also variable. By adjusting the orientation of the second wavelength selection element 122, the amount of light having the wavelength λ ₂ fed back from the second wavelength selection element 122 to the active layer 103 of the semiconductor laser diode 100 can be adjusted. The laser light source 2 includes second azimuth adjusting means for adjusting the azimuth of the second wavelength selection element 122 as described above.

Specific examples of the laser light source 2 are as follows. The resonant wavelength λ ₀ of the distributed feedback resonator in the semiconductor laser diode 100 is 969 nm, the central wavelength λ ₁ of Bragg reflection in the first wavelength selection element 121 is 976 nm, and the Bragg reflection in the second wavelength selection element 122 is The center wavelength λ ₂ is 959 nm. In this case, the laser light source 2 can oscillate at three wavelengths of wavelength λ ₀ (969 nm), wavelength λ ₁ (976 nm), and wavelength λ ₂ (959 nm). Further, the laser light source 2 can change the oscillation intensity ratio of the three-wavelength laser light while fixing each oscillation wavelength by adjusting the inclination angles of the first wavelength selection element 121 and the second wavelength selection element 122, respectively. it can.

  (Third embodiment)

  FIG. 8 is a diagram showing a configuration of the laser light source 3 according to the third embodiment. The laser light source 3 shown in this figure includes a semiconductor laser diode 100, a first wavelength selection element 121, and a collimator lens 130.

  Each of the semiconductor laser diode 100, the first wavelength selection element 121, and the collimator lens 130 in the third embodiment is substantially the same as that in the first embodiment. However, in the first embodiment, the light transmitted through the first wavelength selection element 121 becomes the output light from the laser light source 1, whereas in the third embodiment, the light is output from the second end face 102 of the semiconductor laser diode 100. The emitted light becomes output light from the laser light source 3. Therefore, in the third embodiment, the reflectance of the first wavelength selection element 121 is preferably 90% or more.

The laser light source 3 according to the third embodiment can also oscillate at two wavelengths of wavelength λ ₀ and wavelength λ ₁ , and each oscillation wavelength is fixed by adjusting the tilt angle of the first wavelength selection element 121. The oscillation intensity ratio of the two-wavelength laser light can be changed as it is.

  (Fourth embodiment)

  FIG. 9 is a diagram showing a configuration of the laser light source 4 according to the fourth embodiment. The laser light source 4 shown in this figure includes a semiconductor laser diode 100, a first wavelength selection element 121, a second wavelength selection element 122, and a collimator lens 130.

  The semiconductor laser diode 100, the first wavelength selection element 121, the second wavelength selection element 122, and the collimator lens 130 in the fourth embodiment are substantially the same as those in the second embodiment. However, in the second embodiment, the light transmitted through the first wavelength selection element 121 or the second wavelength selection element 122 is output light from the laser light source 2, whereas in the fourth embodiment, the semiconductor laser diode 100 The light output from the second end face 102 becomes output light from the laser light source 4. Therefore, in the fourth embodiment, the reflectivity of each of the first wavelength selection element 121 and the second wavelength selection element 122 is preferably 90% or more.

The laser light source 4 according to the fourth embodiment can also oscillate at three wavelengths of wavelengths λ ₀ , λ ₁ , and λ ₃ , and the respective tilt angles of the first wavelength selection element 121 and the second wavelength selection element 122. By adjusting the oscillation intensity ratio, it is possible to change the oscillation intensity ratio of the three-wavelength laser light while fixing each oscillation wavelength.

  (Fifth embodiment)

  FIG. 10 is a diagram showing the configuration of the laser light source 5 according to the fifth embodiment. The laser light source 5 shown in this figure includes a semiconductor laser diode 110, a first wavelength selection element 121, and a collimator lens 130. The first wavelength selection element 121 and the collimator lens 130 in the fifth embodiment are the same as those in the first embodiment.

FIG. 11 is a view showing the first end face 111 of the semiconductor laser diode 110 included in the laser light source 5 according to the fifth embodiment. The semiconductor laser diode 110 has a plurality of active layers 113 extending in the z direction between the first end surface 111 and the second end surface 112 facing each other. The plurality of active layers 113 are arranged in parallel on the yz plane. Each of the plurality of active layers 113 has a layered shape. For example, the arrangement pitch in the y direction is 300 μm to 500 μm, the width in the y direction is 100 μm to 200 μm, and the thickness in the x direction is 1 cm in width. 1 μm. The semiconductor laser diode 110 is a so-called DFB type, and a distributed feedback type resonator that resonates light having a wavelength λ ₀ included in the light emission spectrum in each active layer 113 is formed. The first end surface 111 facing the first wavelength selection element 121 is coated with a reflection reducing film.

The first wavelength selection element 121 generates at least a part of light output from the first end face 111 of the semiconductor laser diode 110 and having a wavelength λ ₁ that is included in the light emission spectrum of the active layer 113 and is different from the wavelength λ _0. Bragg reflection is performed, and at least a part of the light having the wavelength λ ₁ reflected by the Bragg reflection is returned to the active layer 113. The first wavelength selection element 121 transmits a part of the incident light and uses the transmitted light as output light from the laser light source 5.

The relative orientation of the first wavelength selection element 121 with respect to the semiconductor laser diode 110 is variable. By adjusting the orientation of the first wavelength selection element 121, the amount of light having the wavelength λ ₁ that is fed back from the first wavelength selection element 121 to the active layer 113 of the semiconductor laser diode 110 can be adjusted. The laser light source 5 includes first azimuth adjusting means for adjusting the azimuth of the first wavelength selection element 121 as described above.

  The collimator lens 130 is provided between the semiconductor laser diode 110 and the first wavelength selection element 121. The collimator lens 130 collimates the light output from the first end surface 111 of the semiconductor laser diode 110 in the x direction perpendicular to the active layer 113 and outputs the collimated lens 130 to the first wavelength selection element 121. In general, the divergence angle of light output from the first end face 111 of the semiconductor laser diode 110 is about 8 degrees in the y direction (Slow Axis direction) parallel to the layer of the active layer 113, while being active. The x direction (Fast Axis direction) perpendicular to the layer 113 is as large as about 30 degrees. Therefore, the collimator lens 130 collimates the light output from the first end face 111 of the semiconductor laser diode 110 in the x direction (Fast Axis direction) perpendicular to the layer of the active layer 113.

The laser device 5 according to the fifth embodiment can also oscillate at two wavelengths of wavelength λ ₀ and wavelength λ ₁ , and fix each oscillation wavelength by adjusting the tilt angle of the first wavelength selection element 121. The oscillation intensity ratio of the two-wavelength laser light can be changed as it is. In the fifth embodiment, since a plurality of active layers 113 are arranged in parallel in the semiconductor laser diode 110, a laser beam having a greater intensity can be obtained.

  (Sixth embodiment)

  FIG. 12 is a diagram showing a configuration of the laser light source 6 according to the sixth embodiment. The laser light source 6 shown in this figure includes a semiconductor laser diode 110, a first wavelength selection element 121, a second wavelength selection element 122, and a collimator lens 130.

  Each of the semiconductor laser diode 110, the first wavelength selection element 121, and the collimator lens 130 in the sixth embodiment is the same as that in the fifth embodiment. The collimator lens 130 is provided between the semiconductor laser diode 110 and the first wavelength selection element 121 and the second wavelength selection element 122. The collimator lens 130 collimates the light output from the first end face 111 of the semiconductor laser diode 110 in the x direction (Fast Axis direction) perpendicular to the relevant layer of the active layer 113, and the collimated light is the first wavelength selection element. 121 and the second wavelength selection element 122.

The second wavelength selection element 122 is substantially the same as the first wavelength selection element 121, and is included in the light emission spectrum in the active layer 113 among the light output from the first end face 111 of the semiconductor laser diode 110. At least a part of the light having the wavelength λ ₂ different from both the wavelength λ ₀ and the wavelength λ ₁ is Bragg reflected, and at least a part of the Bragg-reflected light having the wavelength λ ₂ is fed back to the active layer 113. The second wavelength selection element 122 transmits a part of the incident light and uses the transmitted light as output light from the laser light source 6. The relationship between the three wavelengths λ ₀ , λ ₁ and λ ₂ is preferably λ ₁ <λ ₀ <λ ₂ or λ ₂ <λ ₀ <λ ₁ .

Just as the relative orientation of the first wavelength selection element 121 with respect to the semiconductor laser diode 110 is variable, the relative orientation of the second wavelength selection element 122 with respect to the semiconductor laser diode 110 is also variable. By adjusting the orientation of the second wavelength selection element 122, the amount of light having the wavelength λ ₂ that is fed back from the second wavelength selection element 122 to the active layer 113 of the semiconductor laser diode 110 can be adjusted. The laser light source 6 includes second azimuth adjusting means for adjusting the azimuth of the second wavelength selection element 122 as described above.

The laser light source 6 according to the sixth embodiment can oscillate at three wavelengths of wavelengths λ ₀ , λ ₁ , and λ ₂ , and the respective tilt angles of the first wavelength selection element 121 and the second wavelength selection element 122. By adjusting the oscillation intensity ratio, it is possible to change the oscillation intensity ratio of the three-wavelength laser light while fixing each oscillation wavelength.

  (Seventh embodiment)

  FIG. 13 is a diagram showing a configuration of a laser light source 7 according to the seventh embodiment. The laser light source 7 shown in this figure includes a semiconductor laser diode 110, a first wavelength selection element 121, a collimator lens 130, and an optical path conversion element 140. The semiconductor laser diode 110, the first wavelength selection element 121, and the collimator lens 130 in the seventh embodiment are the same as those in the fifth embodiment.

  The optical path conversion element 140 is provided between the collimator lens 130 and the first wavelength selection element 121. The optical path conversion element 140 rotates the transverse section of each light beam output from the collimator lens 130 by approximately 90 degrees and outputs the rotated light beam to the first wavelength selection element 121. FIG. 14 is a perspective view showing an optical path conversion element 140 included in the laser light source 7 according to the seventh embodiment. The optical path conversion element 140 has an entrance surface 141 and an exit surface 142 that face each other. The incident surface 141 has a plurality of cylindrical surfaces with a width of 0.5 mm arranged in parallel. These cylindrical surfaces extend at an angle of 45 degrees with respect to the y direction. The number of these cylindrical surfaces is equal to the number of active layers 113 of the semiconductor laser diode 110. That is, these cylindrical surfaces have a one-to-one correspondence with the active layer 113. Similarly, the emission surface 142 has a plurality of cylindrical surfaces with a width of 0.5 mm arranged in parallel. These cylindrical surfaces also extend at an angle of 45 degrees with respect to the y direction. These cylindrical surfaces also have a one-to-one correspondence with the active layer 113.

The laser device 7 according to the seventh embodiment can also oscillate at two wavelengths of wavelength λ ₀ and wavelength λ ₁ , and each oscillation wavelength is fixed by adjusting the tilt angle of the first wavelength selection element 121. The oscillation intensity ratio of the two-wavelength laser light can be changed as it is. In the seventh embodiment, since a plurality of active layers 113 are arranged in parallel in the semiconductor laser diode 110, a laser beam having a greater intensity can be obtained. Furthermore, in the seventh embodiment, by providing the optical path conversion element 140, it is possible to efficiently change the oscillation intensity ratio of the two-wavelength laser light for each of the plurality of active layers 113.

  (Eighth embodiment)

  FIG. 15 is a diagram showing a configuration of the laser light source 8 according to the eighth embodiment. The laser light source 8 shown in this figure includes a semiconductor laser diode 110, a first wavelength selection element 121, a second wavelength selection element 122, a collimator lens 130, and an optical path conversion element 140. The semiconductor laser diode 110, the first wavelength selection element 121, the second wavelength selection element 122, and the collimator lens 130 in the eighth embodiment are the same as those in the sixth embodiment. The optical path conversion element 140 is the same as that in the seventh embodiment.

The laser device 8 according to the eighth embodiment can oscillate at three wavelengths of wavelengths λ ₀ , λ ₁ , and λ ₂ , and the respective tilt angles of the first wavelength selection element 121 and the second wavelength selection element 122. By adjusting the oscillation intensity ratio, it is possible to change the oscillation intensity ratio of the three-wavelength laser light while fixing each oscillation wavelength.

  (Modification)

  The present invention is not limited to the above embodiment, and various modifications can be made. In each of the first and second embodiments, the light transmitted through the wavelength conversion element is output from the laser light source, whereas in each of the third and fourth embodiments, the second of the semiconductor laser diode 100 is used. The light output from the end face 102 was used as the output light from the laser light source. Similarly to this relationship, as a modification of each of the fifth to eighth embodiments, light output from the second end face 112 of the semiconductor laser diode 110 may be output from the laser light source.

DESCRIPTION OF SYMBOLS 1-8 ... Laser light source, 100 ... Semiconductor laser diode, 101 ... 1st end surface, 102 ... 2nd end surface, 103 ... Active layer, 110 ... Semiconductor laser diode, 111 ... 1st end surface, 112 ... 2nd end surface, 113 ... Active layer 121... First wavelength selection element 122. Second wavelength selection element 130. Collimator lens 140.

Claims (5)

A distributed feedback type resonator having an active layer extending between a first end surface and a second end surface facing each other and resonating light having a wavelength λ ₀ included in a light emission spectrum in the active layer is formed. A semiconductor laser diode,
Of the light output from the first end face of the semiconductor laser diode, at least part of the light having a wavelength λ ₁ different from the wavelength λ ₀ included in the light emission spectrum is Bragg reflected, and the Bragg reflected A first wavelength selection element for returning at least a part of light of wavelength λ _{1 to} the active layer;
Adjusting the relative azimuth of the first wavelength selection element with respect to the semiconductor laser diode, and adjusting the amount of light of the wavelength λ ₁ fed back from the first wavelength selection element to the active layer of the semiconductor laser diode First orientation adjusting means for
A laser device comprising: Of the light output from the first end face of the semiconductor laser diode, Bragg-reflects at least a part of light having a wavelength λ ₂ included in the light emission spectrum and different from both the wavelength λ ₀ and the wavelength λ _1. A second wavelength selection element for returning at least a part of the Bragg-reflected light having the wavelength λ _{2 to} the active layer;
Adjusting the relative azimuth of the second wavelength selection element with respect to the semiconductor laser diode, and adjusting the amount of light of the wavelength λ ₂ fed back from the second wavelength selection element to the active layer of the semiconductor laser diode Second azimuth adjusting means for
The laser device according to claim 1, further comprising:   The first laser is provided between the semiconductor laser diode and the first wavelength selection element, and the light output from the first end face of the semiconductor laser diode is collimated in a direction perpendicular to the layer of the active layer, and the first The laser apparatus according to claim 1, further comprising a collimator lens that outputs to the wavelength selection element.   An optical path conversion element that is provided between the collimator lens and the first wavelength selection element and rotates the transverse section of light output from the collimator lens by approximately 90 degrees and outputs the light to the first wavelength selection element is further provided. The laser device according to claim 3. The laser apparatus according to claim 1, wherein the semiconductor laser diode includes a plurality of active layers arranged in parallel on a predetermined plane.

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