WO2006009191A1

WO2006009191A1 - Light path switchover device

Info

Publication number: WO2006009191A1
Application number: PCT/JP2005/013354
Authority: WO
Inventors: Masayuki Togawa; Morio Kobayashi
Original assignee: Nabtesco Corporation
Priority date: 2004-07-21
Filing date: 2005-07-21
Publication date: 2006-01-26

Abstract

[PROBLEMS] A light path switchover device where unwanted reduction in a light transmission factor and loss in light can be more effectively prevented than a case in which a prism is used to switch over between light paths. [MEANS FOR SOLVING PROBLEMS] A light path switching device (10) uses light reflection at a pair of mirrors (71, 72) to switch a light path for a light beam (11). The mirrors (71, 72) are moved on to the light path by a drive actuator (76) with their reflection surfaces (71r, 72r) held parallel to each other by a mirror fixation member, so that high accuracy is not required for the movement.

Description

Specification

Optical path switching device

Technical field

The present invention relates to an optical path switching device that is used in the optical communication field such as an optical information network and an optical LAN and switches an optical path.

Background art

Conventionally, as an optical path switching device that switches an optical path, an apparatus that displaces an optical path of a light beam using a parallelogram prism is known (for example, see Patent Document 1).

[0003] In the conventional optical path switching device, the non-reflective film is coated on the incident surface and the exit surface that transmit the light beam among the four surfaces of the parallelogram prism, and the two reflective surfaces that reflect the light beam are coated. Each reflective film is coated.

Patent Document 1: Japanese Unexamined Patent Publication No. 2003-21756 (Page 4, Figure 3)

Disclosure of the invention

Problems to be solved by the invention

[0004] In the conventional optical path switching device, it is necessary to apply a non-reflective film or a reflective film coating to the four surfaces of the parallelogram prism, which increases the manufacturing cost. In addition, even an anti-reflective film has an extremely strong reflectivity of about 0.1%, so this non-reflective film is one of the factors that lower the light transmittance (that is, cause a loss of light). It was. Furthermore, since the material of the prism (for example, glass) has polarization dependency, which is a property that the transmittance varies depending on the polarization, the polarization dependent loss (Polarization Dependent Loss) required for optical communication. ) There is a problem that it is necessary to use materials with carefully selected quality without striae to satisfy!

[0005] Thus, for example, Patent Document 2 discloses a technique for switching the optical path by a pair of facing mirrors instead of the parallelogram prism. Each mirror has a reflective surface formed by a reflective coating on the surface of a substrate such as a plate glass. This optical path switching device using a pair of mirrors does not require the light beam to pass through an anti-reflection film or the inside of the prism as in the case of using a prism, so that it is possible to prevent unnecessary reduction in transmittance, and polarization dependent loss. The It is also suitable for suppressing. However, since this conventional apparatus switches the optical path by inserting and removing only one of the pair of mirrors on the optical path, the mirrors can be moved with high accuracy so that the relative positions of the mirrors are not shifted. It is necessary to move on the optical path. When the relative displacement of each mirror occurs, the reflection characteristics of the mirror change, and the connection state of the input / output when the optical path is switched deteriorates, resulting in an increase in light loss.

Patent Document 2: JP-A-5-110180 (Page 2 and Figure 4)

[0006] The present invention has been made to solve the conventional problems, and by using the reflection of a mirror to switch the optical path (as compared to the case of using a prism), the transmittance is unnecessarily reduced and the light is reduced. An object of the present invention is to provide an optical path switching device which can eliminate the need for highly accurate movement of the mirror while effectively preventing loss.

Means for solving the problem

[0007] The optical path switching device of the present invention comprises an input means for inputting a light beam from the outside, an output means for outputting the light beam to the outside, and a reflecting surface for displacing the light path of the light beam by reflecting the light beam. A first mirror having a second mirror having a reflecting surface that displaces the optical path of the light beam by further reflecting the light beam reflected by the first mirror, and from the input unit to the output unit Moving means for moving the first mirror and the second mirror on the optical path of the light beam until the first mirror and the second mirror have reflecting surfaces parallel to each other. In this state, it is fixed to the mirror fixing member.

[0008] With this configuration, the optical path switching device of the present invention switches the optical path by reflection of the first mirror and the second mirror, thereby comparing the light path switching device with the conventional device using a parallelogram prism. However, since it is not necessary to transmit through the antireflective film or the prism, it is possible to effectively prevent an unnecessary decrease in transmittance and loss of light. Also, the optical path can be switched by moving the pair of mirrors onto the optical path while holding the reflecting surfaces of the first mirror and the second mirror in parallel by the mirror fixing member. As a result, when the pair of mirrors is moved (switching the optical path) by the moving means, even if the position of the mirror with respect to the light beam changes slightly, the light reflection characteristics do not deteriorate. For example, if the diameter of the light beam is 0.5 mm and the allowable loss of light when switching the optical path is 0.2 dB, the angle deviation of the optical axis to the light output means Is allowed up to ± 1.0 degree. According to the present invention, setting the angle deviation of the optical axis within this allowable range can be achieved relatively easily without the mirror moving by the moving means with high accuracy. Since it is not necessary to move the mirror with high accuracy, the apparatus cost can be reduced and the assembly process can be simplified.

[0009] The mirror moving means in the present invention may be any means that moves the mirror fixing member that fixes each mirror. That is, each mirror moves via the mirror fixing member.

[0010] According to this configuration, these mirrors can be moved on the optical path in a stable state in which the relative positions of the first and second mirrors do not change.

The mirror fixing member has a first surface portion and a second surface portion parallel to each other, fixes the first mirror along the first surface portion, and fixes the second mirror to the first surface portion. It can be configured to be fixed along the two face portions.

[0012] The first surface portion and the second surface portion of the mirror fixing member can be processed in parallel relatively easily by an existing machining facility or the like. If the first and second mirrors are fixed along these surface portions, the reflecting surfaces of the mirrors can be arranged in parallel relatively easily and with high accuracy. The mirror fixing member may be formed of a material force, such as ceramics, glass, silicon, or metal, which is relatively easy to machine and easily confirms the parallelism of the first and second surface portions.

[0013] When each mirror is fixed to the mirror fixing member, the reflection surface of the first mirror is aligned with the first surface portion of the mirror fixing member, and the reflection surface of the second mirror is fixed to the mirror fixing member. It is preferable to match with the second surface portion of the member.

[0014] According to this configuration, the reflecting surfaces of the mirrors are aligned with the first and second surface portions of the mirror fixing member processed and processed in parallel, so that the reflecting surfaces of the mirrors can be more easily and in parallel. It can be obtained with high accuracy.

[0015] It is preferable that the first mirror and the second mirror are fixed to the mirror fixing member with their respective reflecting surfaces facing each other.

[0016] According to this configuration, the incident light ray directly hits the reflection surface and is reflected (for example, it is not necessary to transmit through a material such as a plate glass that supports the mirror reflection film). Reduction can be achieved, and the compatibility with a large amount of light can also be improved.

[0017] The first mirror and the second mirror are opposed to the first surface portion and the second surface portion of the mirror fixing member. Thus, it is preferable to fix in a state of direct contact without interposing a foreign substance (for example, adhesive). As the fixing method, for example, a fusion welding method (fusion or welding) or a brazing method can be employed.

[0018] According to this, it is possible to arrange the mirror reflecting surfaces of each mirror in parallel with higher accuracy in accordance with each surface portion of the mirror fixing member formed in parallel.

In the optical path switching device according to the present invention, the reflection surface of the first mirror has a lower reflectance for light rays having a wavelength within the predetermined range than that for light rays having wavelengths outside the predetermined range. It can be set.

[0020] In this configuration, the reflecting surface of the first mirror transmits a light beam having a wavelength within a predetermined range. According to this, the optical path switching device of the present invention can switch the optical path by taking out only a light beam having an arbitrary wavelength. The first mirror can set the thickness in the light transmission direction (thickness of the substrate such as plate glass and the reflection film) to be thinner than that of the prism, so that the polarization dependent loss due to the transmission of the light can be kept extremely small. .

The invention's effect

[0021] According to the optical path switching device of the present invention, by using the reflection of the mirror for switching the optical path (as compared with the case of using a prism), it is possible to effectively prevent unnecessary reduction in transmittance and light loss. The mirror can be moved with high accuracy.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0023] (First embodiment)

First, the configuration of the optical path switching device according to the first embodiment will be described.

As shown in FIG. 1, an optical path switching apparatus 10 according to the present embodiment includes a fiber collimator 20 as input means for receiving a light beam 11, and a fiber collimator support plate 30 that supports the fiber collimator 20. , Fiber collimators 40 and 50 as output means for outputting the light beam 11, a fiber collimator support plate 60 that supports the fiber collimators 40 and 50, and a first mirror that displaces the optical path of the light beam 11 by reflecting the light beam 11. A mirror 71 as a second mirror, a mirror 72 as a second mirror that displaces the optical path of the light beam 11 by reflecting the light beam 11 reflected by the mirror 71, a mirror support plate 75 that supports the mirrors 71 and 72, and a fiber. Collime 1-input, 2-output IX 2 equipped with a drive actuator 76 such as a solenoid actuator as a moving means for moving the mirrors 71 and 72 on the optical path of the light beam 11 from the data 20 to the fiber collimator 50 It is an optical path switching device. These mirrors 71 and 72 are fixed to a mirror fixing member (not appearing in FIGS. 1 and 2) with their reflecting surfaces 71r and 72r being parallel to each other. By fixing this mirror fixing member to the mirror support plate 75, each mirror 71, 72 is supported by the mirror support plate 75 via the mirror fixing member. The drive actuator 76 is connected to the mirror support plate 75. With this configuration, the pair of mirrors 71 and 72 are moved on the optical path by the drive actuator 76 with their reflecting surfaces held in parallel by the mirror fixing member, so that high accuracy is required for the movement. And not. The movement can be performed in a stable state in which the relative positions of the mirrors 71 and 72 do not change.

The fiber collimator 20 includes an optical fiber 21 and a lens 22. Here, the optical fiber 21 is formed with an input port 21a for inputting the light beam 11 as an external force. The light beam 11 output from the lens 22 of the fiber collimator 20 is a parallel beam.

The fiber collimator 40 includes an optical fiber 41 and a lens 42. Here, the optical fiber 41 is formed with an output port 41a for outputting the light beam 11 to the outside. Similarly, the fiber collimator 50 includes an optical fiber 51 and a lens 52. Here, the optical fiber 51 is formed with an output port 51a for outputting the light beam 11 to the outside.

Further, as shown in FIG. 2, the mirrors 71 and 72 are arranged in parallel to each other at an angle at which the light beam 11 is incident at about 45 °. In each of the mirrors 71 and 72, a substrate 71b or 72b made of a sheet glass cover is coated with a reflective film for forming the reflecting surfaces 71r and 72r. For the material of the substrate 71b, plastic, ceramics, metal, or the like can be used in addition to the force using glass here.

[0028] Next, the operation of the optical path switching device 10 will be described.

[0029] As shown in FIG. 1 (a), when the mirrors 71 and 72 are moved below the optical path of the light beam 11 by the drive actuator 76 (that is, the pair of mirrors 71 and 72 also retracts the force on the light beam 11). When moved to the position), the light beam 11 emitted from the fiber collimator 20 goes straight without entering the mirrors 71 and 72 and enters the fiber collimator 40. That is, the input port 21a of the fiber collimator 20 is connected to the output port 41a of the fiber collimator 40. On the other hand, as shown in FIG. 1B, when the mirrors 71 and 72 are moved on the optical path of the light beam 11 by the drive actuator 76, the light beam 11 emitted from the fiber collimator 20 enters the mirror 71 and enters the mirror 71. The optical path is displaced by the reflecting surface 71r of the mirror 72, and further enters the mirror 72. The optical path is displaced by the reflecting surface 72r of the mirror 72, and then enters the fiber collimator 50. That is, the input port 21a of the fiber collimator 20 is connected to the output port 51a of the fiber collimator 50. In this way, the optical path switching device 10 switches the optical path of the light beam 11 by inserting and removing the mirrors 71 and 72 with respect to the optical path of the light beam 11.

As shown in FIG. 2, the displacement of the optical path of the light beam 11 uses reflection on the reflection surface 71r of the mirror 71 and reflection on the reflection surface 72r of the mirror 72. Therefore, in principle, the width 70a of the mirrors 71 and 72 (the width of the fiber collimator 20 in the light emitting direction) may be slightly longer than the beam diameter of the light beam 11. Considering the ease of assembly and handling of the optical path switching device 10, the width 70a is, for example, 3 mm. Further, the width 70b of the mirrors 71 and 72 (the width in the direction perpendicular to the light emitting direction of the fiber collimator 20) is determined by the required displacement 11a (see FIG. 1) of the optical path of the light beam 11, and is, for example, 5 mm.

[0031] The pair of mirrors 71 and 72 are installed in a state where the reflecting surfaces 71r and 72r face each other. The light beam 11 is reflected by directly hitting the reflecting surfaces 71r and 72r that do not pass through the substrates 71b and 72b. Therefore, it is possible to effectively prevent unnecessary reduction in transmittance and light loss compared to the conventional case where light passes through the antireflection film or the inside of the prism.

[0032] Further, the optical path switching device 10 allows the light beam 11 to pass through the air instead of transmitting the inside of the prism formed of glass or the like to the light beam 11 as in the prior art. The insertion loss can be reduced as compared with the conventional case.

[0033] In addition, since the optical path switching device 10 does not need to be provided with a small and highly accurate parallelogram prism as in the prior art, the manufacturing cost can be reduced as compared with the prior art.

[0034] It is difficult to coat a specific film only on a specific surface of a small component. On the other hand, in the case of small parts coated with multiple types of films, such as a non-reflective film coated on the transmissive surface and a reflective film coated on the reflective surface, like the parallelogram prism of the conventional optical path switching device, There may be a problem in the manufacturing process that the non-reflective film reaches the surface or the reflective film reaches the transmissive surface. However, since the optical path switching device 10 only reflects the mirrors 71 and 72 without transmitting the light beam 11, the coating of the reflective film on the mirrors 71 and 72 is applied to a surface other than the reflection surface of the light beam 11. It ’s okay to go over there. Therefore, the optical path switching device 10 can be easily manufactured even if the accuracy of the coating of the film is low compared to the conventional case.

[0035] (Second embodiment)

The configuration of the optical path switching device according to the second embodiment will be described.

Note that, in the configuration of the optical path switching apparatus according to the present embodiment, the same reference numerals are given to the same configurations as those of the optical path switching apparatus 10 (see FIG. 1) according to the first embodiment. Detailed description will be omitted.

As shown in FIG. 3, the configuration of the optical path switching device according to the present embodiment includes a mirror fixing member 80 having a surface portion 81 as a first surface portion and a surface portion 82 as a second surface portion. The configuration is the same as that of the optical path switching device 10. The surface portions 81 and 82 of the mirror fixing member 80 are formed in parallel to each other by cutting using an existing machining facility. By fixing the mirrors 71 and 72 along the surface portions 81 and 82, the reflecting surfaces 71r and 72r of the mirrors 71 and 72 can be installed in parallel. The surface portions 81 and 82 of the mirror fixing member 80 face outward, and are configured to face the surfaces of the mirrors 71 and 72 (incident surface of the light beam 11). In this case, the reflecting surfaces 71r and 72r are installed in parallel with respect to the surfaces of the mirrors 71 and 72, respectively. Alternatively, each of the surface portions 81 and 82 may be formed inward (for example, on the inner surface having a concave cross section) so as to face the back surface of each of the mirrors 71 and 72. In this case, the reflecting surfaces 71r and 72r are installed in parallel with the back surfaces of the mirrors 71 and 72 as a reference. In the present embodiment, the mirrors 71 and 72 have their respective surfaces as reflecting surfaces 7 lr and 72 r, and the reflecting surfaces 71 r and 72 r are aligned with the surface portions 81 and 82 of the mirror fixing member 80 (that is, each other). It is fixed so that the faces face each other. By using the reflective surfaces 71r and 72r as a reference, the parallelism between the front and back surfaces of each mirror 71 and 72 is considered. The reflecting surfaces 71r and 72r of the mirrors 71 and 72 can be installed in parallel with higher accuracy in accordance with the parallel of the surface portions 81 and 82 to be engaged.

[0038] Here, the mirrors 71 and 72 have their respective reflecting surfaces 71r and 72r in direct contact with the surface portions 81 and 82 of the mirror fixing member 80 (with a foreign substance such as an adhesive in between). It is fixed without any intervention. According to this, the reflecting surfaces 71r and 72r of the mirrors 71 and 72 can be arranged in parallel with higher accuracy in accordance with the surface portions 81 and 82 of the mirror fixing member 80 formed in parallel. If the mirror fixing member 80 is made of glass, the mirrors 71 and 72 having the same glass material capacity can be relatively easily fixed by welding.

In addition, the mirror support plate 75 supports the mirrors 71 and 72 via the mirror fixing member 80.

The moving means 76 moves the pair of mirrors 71 and 72 via the mirror support plate 75 and the mirror fixing member 80. Thus, the pair of mirrors 71 and 72 can be moved on the optical path in a stable state where the relative positions of the mirrors 71 and 72 do not change.

[0040] As described above, in the optical path switching device according to the present embodiment, the mirrors 71 and 72 are fixed to the mutually parallel surface portions 81 and 82 of the mirror fixing member 80, respectively. The work of making the reflecting surfaces 71r and 72r parallel to each other can be facilitated.

[0041] (Third embodiment)

The configuration of the optical path switching device 310 according to the third embodiment will be described.

FIG. 4 shows the overall configuration of the optical path switching device 310. Of the configurations of the optical path switching apparatus 310 according to the present embodiment, the same reference numerals are given to the same configurations as those of the optical path switching apparatus 10 (see FIG. 1) according to the first embodiment described above. Detailed description is omitted. The first mirror 371 is basically different from the first embodiment. The mirror 371 in the present embodiment is set to have a low reflectance relative to a light beam having a wavelength within a predetermined range compared to a reflectivity for a light beam having a wavelength outside that range. That is, the reflecting surface 371r of the mirror 371 has a filter function, and is basically set to transmit only light having a wavelength within a predetermined range. The other mirror 72 is a total reflection mirror as in the first embodiment.

FIG. 6 shows the relationship between the reflectance and wavelength of the first mirror 371 in the present embodiment. The first mirror 371 has a reflectance of 80% or more of light with a high wavelength λ 1 within a specific range, and a reflectance of light with a low wavelength λ 2 within another specific range of 30% or less. The [0044] As shown in Fig. 4 (a), when the pair of mirrors 371 and 72 are in a position where the force of the light beam 11 is retracted, the input means (fiber collimator 20) includes the wavelengths λ1 and 2 emitted. The light beam 11 travels straight without entering the mirrors 71 and 72, and is emitted from the output means (fiber collimator 40) to the outside through the output port 41a. On the other hand, as shown in FIGS. 4 (b) and 5, when the pair of mirrors 371 and 72 are moved by the drive actuator 76 to a position where the mirror 11 intercepts the light beam 11 (on the optical path of the light beam 11), the wavelength λ 1 of the light beam 11 Are reflected by the first mirror 371 and the second mirror 72, and emitted from another output means (fiber collimator 50) through the output port 51a to the outside. Of the light beam 11, light having a wavelength of 2 travels straight through the first mirror 371 and is emitted to the outside from the output means (fiber collimator 40) through the output port 41 a.

According to the optical path switching device 310 of the present embodiment, the light with the wavelength λ 2 is always output from the output port 41a regardless of the movement of the mirrors 71 and 72, and the light with the wavelength λ 1 is moved by the mirrors 71 and 72. Depending on the output, it is output from either output port 41a or 51a. This makes it possible to divide the light according to the desired wavelength. For example, an optical switch for an optical communication system (OADM system) that allocates an optical signal for each wavelength can be realized.

[0046] (Fourth embodiment)

The switching means including a mirror having a filter function as shown in the third embodiment can be used by incorporating a plurality of switching means in one optical path switching device. One example is shown as the fourth embodiment. The switching means here includes a pair of mirrors, a mirror fixing member for fixing these mirrors, a mirror support plate for moving the mirrors, and a drive actuator, and is responsible for switching the optical path in the optical path switching device. It is a partial element. FIG. 7 is a view of the optical path switching device 410 according to the fourth embodiment as well. In addition, about the structure similar to the structure of the optical path switching apparatus 10 which concerns on 1st Embodiment mentioned above, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

The optical path switching device 410 according to the present embodiment is also a 1 × 2 optical path switching device with 1 input and 2 outputs, as in the other embodiments. One input means (fiber collimator 20) is provided with a pair of mirrors (first mirror 711 and second mirror 721) as the first switching means 491, and the other output means (fiber collimators 40, 50). Side as second switching means 492 A pair of mirrors (first mirror 712 and second mirror 722) are arranged. Each pair of mirrors 711, 721 and 712, 722 is fixed to a mirror fixing member (not shown), and can be moved by a drive actuator via a mirror support plate. FIG. 8 is a characteristic diagram showing the relationship between the reflectance and wavelength of each of the first mirrors 711 and 712. The first mirror 711 in the first switching means 491 has a reflectance of light having a high wavelength λ 1 within a specific range of 80% or more, and an intermediate wavelength λ 2 and a low wavelength λ 3 within another specific range. The reflectance of light is 30% or less. On the other hand, the first mirror 712 in the second switching means 492 has a reflectance of 80% or more for the light of the intermediate wavelength 2 and a reflectance of 30% for the light of the other high wavelength λ 1 and low wavelength λ 3. It is as follows. Each of the second mirrors 721 and 722 is a total reflection mirror.

[0048] The table below shows the switching conditions of the optical paths by these mirrors. Table 1 shows the wavelength of light emitted from the output port 41a, and Table 2 shows the wavelength of light emitted from the output port 51a. Each is shown. A fiber collimator 20 as an input means emits a light beam 11 including each wavelength 1, λ 2 and 3. For the first and second switching means in the table, the state where each mirror has moved onto the light beam is indicated as “ΟΝ”, and the state where each mirror is retracted from the light beam is indicated as “OFF”.

[0049] [Table 1]

[0050] [Table 2]

According to the optical path switching device 410 shown in the present embodiment, it becomes possible to divide light according to the three types of wavelengths λ 1 to 3. In the present embodiment, two switching means are provided in series. However, the present invention is not limited to this, and a plurality of (two or more) switching means are provided in series or in parallel. It can also be provided. Even when a plurality of switching means are provided, the mirrors need not be moved with high accuracy because the reflecting surfaces of the pair of mirrors in each switching means are kept parallel. In addition, since it is not necessary to match the positions of the switching means with high accuracy, the assembly process of the apparatus can be simplified and the manufacturing cost can be reduced.

Industrial applicability

[0052] As described above, the optical path switching device according to the present invention uses the reflection of the mirror for switching the optical path, thereby reducing unnecessary transmission loss and light transmission (as compared to the case of using a prism). As an optical path switching device used in the optical communication field such as optical information network and optical LAN (Local Area Network), it has the effect of eliminating the need for high-precision movement of this mirror while effectively preventing loss. Useful.

Brief Description of Drawings

FIG. 1 (a) is a perspective view of an optical path switching device 10 according to the first embodiment of the present invention, and FIG. 1 (b) is a perspective view showing a state in which the optical path is switched in (a).

2 is a top view of the vicinity of a mirror of the optical path switching device 10 shown in FIG. 1 (b).

[FIG. 3] (a) is a perspective view of the vicinity of a mirror of an optical path switching device according to a second embodiment of the present invention, and (b) is a top view of (a).

[Fig. 4] (a) is a perspective view of an optical path switching device 310 according to a third embodiment of the present invention, and (b) is this view.

FIG. 6 (a) is a perspective view showing a state where the optical path is switched.

FIG. 5 is a top view of the vicinity of a mirror of the optical path switching device 310 shown in FIG. 4 (b).

FIG. 6 is a characteristic diagram of the first mirror 371 shown in FIG.

FIG. 7 is a top view of an optical path switching device 410 according to a fourth embodiment of the present invention.

FIG. 8 is a characteristic diagram of first mirrors 711 and 712 shown in FIG.

Explanation of symbols

[0054] 10, 310, 410 Optical path switching device

11 rays

20 Fiber collimator (input means)

40, 50 Fiber collimator (output means)

71, 371, 711, 712 mirror (first mirror) 72, 372, 721, 722 Mirror (second mirror) 71r, 371r (first mirror) reflecting surface 72r, 372r (second mirror) reflecting surface 76 Drive actuator (moving means) 80 Mirror fixing member

81 face part (first face part)

82 face part (second face part)

Claims

The scope of the claims

[1] An input means for inputting a light beam from the outside, an output means for outputting the light beam to the outside, a first mirror having a reflecting surface for displacing the light path of the light beam by reflecting the light beam, A second mirror having a reflecting surface for displacing the light path of the light beam by further reflecting the light beam reflected by the first mirror; and the first mirror on the light path of the light beam from the input means to the output means. And a moving means for moving the second mirror, and the first mirror and the second mirror are fixed to the mirror fixing member in a state in which the respective reflecting surfaces are parallel to each other. Characteristic optical path switching device.

[2] The moving means according to claim 1, wherein the moving means moves the first mirror and the second mirror on an optical path of the light beam by moving the mirror fixing member. Optical path switching device.

[3] The mirror fixing member has a first surface portion and a second surface portion which are parallel to each other, fixes the first mirror along the first surface portion, and the second mirror is the first surface portion. The optical path switching device according to claim 1, wherein the optical path switching device is fixed along the surface portion of 2.

[4] The reflective surface of the first mirror is aligned with the first surface portion of the mirror fixing member, and the reflective surface of the second mirror is aligned with the second surface portion of the mirror fixing member. The optical path switching device according to claim 3.

[5] The optical path switching device according to claim 3 or 4, wherein the first mirror and the second mirror are fixed to the mirror fixing member in a state where the reflecting surfaces face each other.

[6] The first mirror and the second mirror are fixed in a state of being in direct contact with the first surface portion and the second surface portion of the mirror fixing member without interposing foreign matter therebetween. The optical path switching device according to claim 3.

[7] The reflective surface of the first mirror is characterized in that the reflectance with respect to a light beam having a wavelength within a predetermined range is set to be lower than the reflectance with respect to a light beam with a wavelength outside the range. The optical path switching device according to claim 1 or 2.