JP2006030866A - Optical switch and multichannel type optical switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical switch which is excellent in response speed and further miniaturized by decreasing the number of components. <P>SOLUTION: The optical switch 1 switches a first optical path state in which light is transmitted from a first light propagation path 4 to a second light propagation path 5 and a second light optical path state in which the light is transmitted from the first light propagation path 4 to a third light propagation path 6. In the first optical path state, the outer side face of a light transmissive piezoactuator 11 is separated from a second fixing member 3 side with a gap, thus the light propagating in the first light propagation path 4 is totally reflected on a first plane 13a and guided into the second light propagation path 5. In the second optical path state, the light transmissive piezoactuator 11 is extended in the thickness direction and the first and the second planes 13a and 14a are made tightly contact with each other, thus the light made incident to the first light propagation path 4 is guided into the third light propagation path 6. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical switch and a multi-channel optical switch that can switch a connection state between a plurality of optical propagation paths, and more specifically, an optical path changing portion is configured using a translucent piezoelectric actuator. The present invention relates to an optical switch and a multi-channel optical switch.

  Conventionally, various optical switches are used in the optical communication field. In a conventional general optical switch, an optical fiber or a mirror as an optical path constituent member is moved by a mechanical driving device using an electromagnet. Such an optical switch involves a mechanical operation using an electromagnet, and thus it is difficult to reduce the size and power consumption of the apparatus. It has also been difficult to increase the switching response speed.

  An example of an optical switch that solves the above problems is disclosed in Patent Document 1 below. That is, as shown in FIG. 7, in the optical switch 101, the mirror 103 is disposed on the substrate 102 so as to be movable in the direction perpendicular to the surface of the substrate 102. The substrate 102 is formed with a plurality of fiber placement grooves 104 for fixing the optical fiber. First to fourth optical fibers 105 to 108 are connected to the substrate 102 using a plurality of fiber arrangement grooves 104. The mirror 103 is connected to the substrate 101 via needles 109 and 110 that can be elastically deformed.

  In a state where no electrostatic force is applied, the mirror 103 is located away from the substrate 102, and when the electrostatic force is applied, it can be moved to the substrate 102 side. The movement of the mirror 103 can change the light propagation path between the optical fibers 105 to 108.

  However, the optical switch 101 described in Patent Document 1 has a problem in that the structure is complicated and the manufacturing cost increases because the mirror 103 is moved by electrostatic force. Moreover, since electrostatic driving is used, the driving voltage has to be increased. Furthermore, it is difficult to improve the response speed.

As a solution to the above problems, Patent Document 2 below discloses an optical switch using a piezoelectric actuator. As illustrated in FIG. 8, the optical switch 121 includes light transmission paths 122 to 124. Then, due to the displacement of the piezoelectric actuator 125 according to the electric signal from the outside, the optical path changing unit 126 made of a light reflecting member is brought into contact with or separated from the light reflecting surface of the light transmitting unit. As a result, the light A input to the light transmission path 122 is totally reflected by the light reflecting surface of the light transmission section, and is extracted from the light introduction member 126 from the light path that is transmitted to the specific light transmission path 123. It is possible to transmit to the light transmission path 124.
JP 11-119129 A JP 2002-196265 A

  In the optical switch 121 described in Patent Document 2, the position of an optical path changing unit made of a light reflecting member is changed using a piezoelectric actuator 125, thereby switching the optical path. Therefore, it is necessary to configure the piezoelectric actuator so that the optical member constituting the optical path changing unit can be moved.

  On the other hand, the displacement of the piezoelectric actuator is usually much smaller than the movement distance of the optical member as described above. Therefore, to configure the optical switch 121 described in Patent Document 2, a very large piezoelectric actuator has to be prepared. Therefore, it has been difficult to reduce the size of the optical switch. In addition, since the optical member is moved by the displacement of the piezoelectric actuator, the moving distance is large, so that the response speed of the entire optical switch has to be lower than the response speed of the piezoelectric actuator.

  An object of the present invention is to solve the above-mentioned disadvantages of the prior art, further increase the response speed, and further use light that uses a light-transmitting laminated piezoelectric material that can be simplified and downsized. It is an object of the present invention to provide a switch and a multi-channel type optical switch using the optical switch.

  According to the present invention, there is provided an optical switch capable of propagating light incident from a first optical propagation path to a second optical propagation path or a third optical propagation path, the first optical propagation path and The first light propagation path is fixed, and the first reflection surface is provided so that the light incident from the first light propagation path can be reflected and guided to the second light propagation path. The first fixing member having a plane and the third light propagation path are fixed, and the light incident from the first light propagation path is not reflected by the first plane, A second plane as an incident surface that is incident when propagating beyond the plane, and configured so that light incident from the second plane is guided to the third light propagation path; The translucent piezoelectric actuator in which the two fixing members and the first fixing member expand and contract by a piezoelectric effect depending on whether or not a voltage is applied. A light transmission path for propagating light incident from the first light propagation path to the first plane, and light reflected by the first plane is second. The first plane is separated from the second plane of the second fixing member by the presence or absence of voltage application, and the light is reflected by the first plane. The first optical path state and the first plane are in close contact with the second plane of the second fixing member, and light is not reflected by the first plane but is guided to the third optical propagation path. An optical switch is provided that is configured to be able to take the following optical path states.

  In a specific aspect of the optical switch according to the present invention, a second translucent piezoelectric actuator is disposed on the second fixing member, and the second translucent piezoelectric actuator includes the second translucent piezoelectric actuator. A light transmission path that guides light incident from the plane in the second optical path state to the third light propagation path is provided.

  In another specific aspect of the optical switch according to the present invention, when the fourth optical propagation path is fixed to the second fixing member and is in the first optical path state, the fourth optical propagation is performed. When light incident from the path is reflected on the second plane of the second fixing member and guided to the third light propagation path, and is in the second optical path state, the light from the fourth light propagation path The incident light is configured to be guided to the second light propagation path through the second plane and the first plane of the first fixing member.

  In still another specific aspect of the optical switch according to the present invention, a second translucent piezoelectric actuator is disposed on the second fixing member, and the second translucent piezoelectric actuator is a fourth translucent piezoelectric actuator. A light transmission path for guiding light incident from the light propagation path to the second plane, and a light transmission for transmitting light guided from the second plane to the third light propagation path in the second optical path state. Road.

  In still another specific aspect of the optical switch according to the present invention, the translucent piezoelectric actuator includes a piezoelectric layer having a pair of opposing main surfaces and a piezoelectric layer between the pair of main surfaces of the piezoelectric body. A laminated piezoelectric body having a plurality of internal electrodes arranged so as to overlap with each other through the plurality of internal electrodes, wherein at least some of the plurality of internal electrodes are provided with a plurality of the light beams. A window for forming a transmission path is formed.

  In still another specific aspect of the optical switch according to the present invention, the second fixing member is disposed on one surface of the translucent piezoelectric actuator provided on the first fixing member, rather than the translucent piezoelectric actuator. A translucent adhesive film made of a material having excellent adhesion to the flat surface is formed, and the outer surface of the translucent adhesive film is the first flat surface.

  In still another specific aspect of the optical switch according to the present invention, the second fixing member surface facing the first plane has the first fixing member more than the translucent piezoelectric actuator. A translucent adhesive film made of a material having excellent adhesion to one plane is formed, and the outer surface of the translucent adhesive film is the second plane.

  The multi-channel optical switch according to the present invention includes a plurality of optical switches configured according to the present invention, and the plurality of optical switches are connected in series and / or in parallel.

  In the optical switch according to the present invention, the first fixing member includes the translucent piezoelectric actuator, and the first flat surface of the first fixing member is set to the second of the second fixing member depending on whether or not voltage is applied. A first optical path state in which light is reflected from the first plane and light is reflected by the first plane to guide light from the first optical propagation path to the second optical propagation path, and the first plane is the second The second optical path state is such that light is not reflected on the first plane and light is guided from the first optical propagation path to the third optical propagation path. . In addition, the translucent piezoelectric actuator itself has a light transmission path for guiding light from the first light propagation path to the first plane and a light propagation path for guiding light from the first plane to the third light propagation path. Therefore, since the optical path is directly switched by the displacement of the translucent piezoelectric actuator itself, the optical switch can be miniaturized.

  That is, in the conventional optical switch using a piezoelectric actuator, the piezoelectric actuator was used to drive other optical members to switch the optical path, and thus it was difficult to reduce the size. According to the present invention, the translucent piezoelectric actuator itself constitutes a part of the optical path, and the optical path is directly switched by the displacement of the translucent piezoelectric actuator itself, so that it is smaller than the case of driving other members. A translucent piezoelectric actuator can be used. Therefore, it becomes possible to reduce the size of the optical switch.

  In addition, the translucent piezoelectric actuator constitutes a part of the optical path, and the first optical path state and the second optical path state are switched by the expansion and contraction of the translucent piezoelectric actuator. Switching response speed is also increased.

  Therefore, according to the present invention, it is possible to provide a small-sized optical switch with excellent response speed.

  The second light transmitting piezoelectric actuator is arranged on the second fixing member, and light incident from the second plane in the second optical path state is transmitted by the second light transmitting piezoelectric actuator. When configured to be guided to the third light propagation path through the path, the first effect is also obtained by utilizing the piezoelectric effect of the translucent piezoelectric actuator provided on the second fixing member side. Switching can be performed between the optical path state and the second optical path state.

  The fourth light propagation path is fixed to the second fixing member, and when in the first optical path state, light incident from the fourth light propagation path is the second fixing member. When reflected on the second plane and guided to the third optical propagation path and in the second optical path state, the light incident from the fourth optical propagation path is the second plane and the first fixed state. When the light passes through the first plane of the member and is guided to the second light propagation path, both the light incident from the first light propagation path and the light incident from the fourth light propagation path are switched. It becomes possible. In this case, when the second translucent piezoelectric actuator is arranged on the second fixing member, the second translucent piezoelectric actuator can also be used for switching.

  The translucent piezoelectric actuator has a laminated piezoelectric body having a piezoelectric body having first and second surfaces facing each other and a plurality of internal electrodes arranged so as to overlap with each other via a piezoelectric layer, In the multilayer piezoelectric body, at least some of the plurality of internal electrodes are formed with windows for forming the plurality of light transmission paths for propagating light through the multilayer piezoelectric body. In this case, a large amount of displacement can be obtained by using the laminated piezoelectric body, so that the optical path state can be switched reliably between the first optical path state and the second optical path state. Further, when the window is formed in at least a part of the internal electrodes, a light transmission path can be formed in the internal electrode laminated portion, and thus the light-transmitting piezoelectric actuator can be further reduced in size. As a result, the optical switch can be further miniaturized.

  When a translucent adhesive film made of a material having better adhesion to the second plane of the second fixing member than the piezoelectric body is formed on the outer surface of the first translucent piezoelectric actuator. In the second optical path state, the light incident from the first optical propagation path can be reliably incident on the third optical propagation path. Further, when the fourth light propagation path is fixed to the second fixing member, the light incident from the fourth light propagation path is transferred to the second light propagation path in the second optical path state. Can be guided reliably.

  Even when a translucent adhesive film made of a material having better adhesion to the first plane than the translucent piezoelectric actuator is formed outside the second plane of the second fixing member, Similarly, in the second optical path state, the light can be reliably guided to the intended optical propagation path.

  Since the multi-channel optical switch according to the present invention includes a plurality of optical switches configured according to the present invention, each optical switch can be reduced in size, so that the entire multi-channel optical switch can be reduced in size. Can do.

  Hereinafter, the present invention will be clarified by describing specific embodiments of the present invention with reference to the drawings.

  FIG. 1A is a plan view of an optical switch according to the first embodiment of the present invention. The optical switch 1 has first and second fixing members 2 and 3. One end of first and second optical fibers 4 and 5 constituting the first and second light propagation paths is connected to the first fixing member 2. In addition, one end of the third and fourth optical fibers 6 and 7 constituting the third and fourth light propagation paths is fixed to the second fixing member 3.

  In addition, it may replace with the optical fibers 4-7, and may comprise an optical propagation path using another optical waveguide body.

  In the present embodiment, light incident from the first optical fiber 4 is guided to the second optical fiber 5 from the first optical fiber 4, and light incident from the fourth optical fiber 7 is input to the third optical fiber 6. The first optical path state to be guided, the light incident from the first optical fiber 4 is guided to the third optical fiber 6, and the light incident from the fourth optical fiber 7 is guided to the second optical fiber 5. It is configured to be switched between two optical path states.

  The first and second fixing members 2 and 3 have fixing portions 8 and 9 made of a translucent material such as quartz, respectively. The fixing portions 8 and 9 each have a pair of inclined surfaces 8a, 8b, 9a and 9b. One ends of the first and second optical fibers 4 and 5 are fixed to the inclined surfaces 8a and 8b. Further, one ends of the third and fourth optical fibers 6 and 7 are fixed to the inclined surfaces 9a and 9b.

  The first and second optical fibers 4 and 5 are arranged at positions facing each other across a virtual line orthogonal to a first plane 13a described later, and are inclined by an equal angle with respect to the virtual line. .

  On the other hand, the fixing portions 8 and 9 have flat portions 8c and 9c on the side opposite to the inclined surfaces 8a, 8b, 9a and 9b.

  And the 1st, 2nd translucent piezoelectric actuators 11 and 12 are joined to the plane parts 8c and 9c.

  Further, the first and second translucent adhesive films are provided so as to cover the surfaces of the first and second translucent piezoelectric actuators 11 and 12 opposite to the side bonded to the fixing portions 8 and 9. 13 and 14 are bonded together.

  The structure of the translucent piezoelectric actuators 11 and 12 will be described on behalf of the first translucent piezoelectric actuator 11.

  FIG. 1B is a plan sectional view of the translucent piezoelectric actuator 11.

  The translucent piezoelectric actuator 11 has a rectangular parallelepiped piezoelectric body 15 made of piezoelectric ceramics such as lead zirconate titanate ceramics. In the piezoelectric body 15, a plurality of first internal electrodes 16a, 16c, 16e, and 16g and a plurality of second internal electrodes 16b, 16d, 16f, and 16h are alternately overlapped via the piezoelectric layers. Are stacked. The first inner electrodes 16a, 16c, 16e, and 16g are drawn out to one end face 15a of the piezoelectric body 15, and the second inner electrodes 16b, 16d, 16f, and 16h are drawn out to the second end face 15b. Yes. External electrodes 17 and 18 are formed on the first and second end faces 15a and 15b. The first external electrode 17 is electrically connected to the plurality of first internal electrodes 16a, 16c, 16e, and 16g. The second external electrode 18 is connected to the plurality of second internal electrodes 16b, 16d, 16f, and 16h.

  In the translucent piezoelectric actuator 11, the first main surface 15 c side of the piezoelectric body 15 is joined to the flat surface portion 8 c of the fixed portion 8 described above in FIG. The outer surface of the translucent adhesive film 13 laminated on the main surface 15d opposite to the main surface 15c constitutes the first flat surface 13a in the present invention.

  The stacked piezoelectric body 15 having the plurality of internal electrodes 16a to 16h is polarized. That is, in the piezoelectric layer sandwiched between the plurality of internal electrodes, the piezoelectric layers alternately adjacent in the thickness direction are polarized in the opposite direction in the thickness direction. Therefore, by switching the polarity when a DC voltage is applied between the external electrodes 17 and 18, the piezoelectric body 15 extends or contracts in the thickness direction.

  As described above, the multilayer piezoelectric body 15 having the plurality of internal electrodes 16a to 16h can be obtained according to a known multilayer piezoelectric actuator manufacturing method.

  That is, a plurality of ceramic green sheets mainly comprising piezoelectric ceramics such as lead zirconate titanate ceramics are prepared. Thereafter, an internal electrode pattern is formed on the plurality of ceramic green sheets, and the plurality of ceramic green sheets on which the internal electrode pattern is formed are laminated. Then, an appropriate number of plain ceramic green sheets are stacked on the top and bottom, and then pressed in the thickness direction. In this way, a laminate can be obtained. By firing the obtained laminate, the piezoelectric body 15 can be obtained, and the first and second external electrodes 17 and 18 are formed on the end faces 15a and 15b of the piezoelectric body 15 in accordance with a known electrode forming method. do it. In addition, after obtaining a laminated body, you may complete the piezoelectric body 15 and the external electrodes 17 and 18 simultaneously by apply | coating an electrically conductive paste to an end surface, and baking.

  In manufacturing the multilayer piezoelectric body, it is preferable to subject the multilayer piezoelectric body 15 to heat treatment and slow cooling prior to polarization. The effects of such heat treatment and slow cooling treatment will be described in experimental examples to be described later.

  By the way, in the piezoelectric body 15 of the present embodiment, in order to realize the internal light transmission path in the first optical path state shown in FIG. 1B, at least some of the internal electrodes 16a to 16h. A window B is formed on the electrode. This will be described with reference to FIG. 2 (a) and 2 (b) show the positions at which the first internal electrodes 16a shown in FIG. 1 (b) are formed and the height positions at which the second internal electrodes 16d are formed. FIG.

  As shown in FIG. 2A, the first internal electrode 16a has a rectangular shape, and one end is drawn out to the end face 15a. In the internal electrode 16a, window portions B and B are formed at positions facing each other across the center of the piezoelectric body 15.

  Similarly, as shown in FIG. 2B, also in the second internal electrode 16d, windows B and B are formed at positions facing each other in the direction connecting the end faces 15a and 15b across the center of the piezoelectric body. ing. However, as is apparent from FIGS. 2A and 2B, the distance between the windows B in the internal electrode 16d is smaller than the distance between the windows B in the internal electrode 16a located above. Has been. This is because when the optical path X shown in FIG. 1 (b) is realized, the distance between the window portions B and B is, as is clear from FIG. 1 (b), the main surface below the main surface 15a of the piezoelectric body 15. This is because the optical path X is realized by decreasing the distance toward the surface 15d side.

  Accordingly, in the lowermost internal electrode 16h, the pair of windows B and B are adjacently connected to form one window.

  As shown in FIG. 1B, the windows B and B are configured to realize an optical path X, that is, light incident from the illustrated direction on the main surface 15 c of the piezoelectric body 15 is translucent. It is provided so as to be reflected by the first flat surface 13a which is the outer surface of the film 13 and guided again to the main surface 15c side. In other words, the window portions B and B are a plurality of light transmission paths that realize the optical path X, that is, a light transmission path from the main surface 15c to the first plane 13a, and from the first plane 13a to the main surface 15c. In order to form a light transmission path through which the reflected light is transmitted, the plurality of windows B, B are formed.

  As described above, by forming the window portion B for forming the light transmission path in the plurality of internal electrodes 16a to 16h, the translucent piezoelectric actuator 11 can be reduced in size. That is, in the translucent piezoelectric actuator 11 driven as a piezoelectric actuator, when a portion for realizing a light transmission path is provided separately from the portion where the internal electrodes 16a to 16h are laminated, the translucent piezoelectric The size of the actuator must be large. On the other hand, in this embodiment, since the light transmission path is provided in the internal electrode laminated portion for driving as the piezoelectric actuator, the translucent piezoelectric actuator 11 as the piezoelectric actuator having the built-in light transmission path is provided. Miniaturization can be achieved.

  Returning to FIG. 1A, in the present embodiment, the translucent piezoelectric actuator 12 is also fixed to the second fixing portion 9 side, but the translucent piezoelectric actuator 12 is the above translucent piezoelectric actuator. 11 is configured in the same manner. Also in the translucent piezoelectric actuator 12, a translucent adhesive film 14 is laminated on the surface opposite to the side bonded to the fixing portion 9, and the outer surface of the translucent adhesive film 14 is This constitutes the second flat surface 14a in the present invention.

  The translucent adhesive films 13 and 14 are made of a material having flexibility superior in adhesiveness to the second or first plane than the translucent piezoelectric actuators 11 and 12, respectively. Examples of the material constituting the translucent adhesive films 13 and 14 include polyimide and polycarbonate.

  The refractive index of the translucent adhesive films 13 and 14 is desirably the same as that of the piezoelectric material constituting the piezoelectric body 15. If the refractive indexes are the same, the light incident from the first optical fiber 4 or the fourth optical fiber 7 does not change its direction in the translucent adhesive films 13 and 14, so that the third or the third is reliably performed according to the present invention. 2 optical fibers.

  However, the refractive indexes of the first and second light-transmitting adhesive films 13 and 14 may be different from the refractive index of the piezoelectric body 15, and in that case, the light traveling direction in accordance with the refractive index difference. In consideration of the change, the angle of the third and fourth optical fibers 6 and 5 with respect to the main surface 15a of the piezoelectric body 15 may be adjusted.

  Next, the operation of the optical switch 1 will be described. The translucent piezoelectric actuators 11 and 12 realize a state where they are extended in the internal electrode stacking direction and a state where they are contracted due to the piezoelectric effect when a voltage is applied. In FIG. 1A, a voltage is applied to the piezoelectric actuators 11 and 12, and both the piezoelectric actuators 11 and 12 extend in the internal electrode lamination direction, that is, the thickness direction. In this case, the translucent adhesion films 13 and 14 laminated on the outer surfaces of the piezoelectric actuators 11 and 12 are firmly adhered. This state is the second optical path state described above. Since the translucent adhesive films 13 and 14 are firmly adhered, the light incident from the first optical fiber 4 passes through the first fixing portion 8 and is guided into the first translucent piezoelectric actuator 11. It is burned. This light passes through the light transmission path in the first light transmissive piezoelectric actuator 11 and reaches the first flat surface 13 a that is the outer surface of the first light transmissive adhesive film 13. Since the first and second light-transmitting adhesive films 13 and 14 have a refractive index substantially equal to that of the piezoelectric material of the light-transmitting piezoelectric actuators 11 and 12, the light travels straight as it is and the second light-transmitting property is reached. It passes through the adhesion film 14, travels through the light transmission path in the second light transmitting piezoelectric actuator 12, and is guided to the third optical fiber 6 positioned on the extension in the extending direction of the first optical fiber 4.

  On the other hand, the light incident from the fourth optical fiber 7 travels straight in the same manner and is guided to the second optical fiber 5 that extends in the extending direction of the fourth optical fiber 7. This state is the second optical path state.

  Next, when voltages having opposite polarities are applied to the first and second translucent piezoelectric actuators 11 and 12, the first and second translucent piezoelectric actuators 11 and 12 are arranged in the thickness direction as shown in FIG. That is, it shrinks in the internal electrode lamination direction. Therefore, a gap C is generated between the outer surfaces of the first and second translucent adhesive films 13 and 14. That is, the first plane 13a and the second plane 14a are separated from each other. This state is the first optical path state.

  In the first optical path state, the light incident from the first optical fiber 4 passes through the light transmission path in the first translucent piezoelectric actuator 11 and is the outer surface of the first translucent adhesive film 13. It reaches the first plane 13a. In the first plane 13a, air exists outside, so that the light is totally reflected by the first plane 13a. And since the 1st, 2nd optical fibers 4 and 5 are arrange | positioned so that it may make an equal angle with respect to the virtual line orthogonal to the 1st plane 13a as mentioned above, the reflected light is 1st. 2 to the optical fiber 5. Similarly, the light incident from the fourth optical fiber 7 is totally reflected by the above-described second plane 14 a of the translucent adhesive film 14 and guided to the third optical fiber 6.

  Therefore, in the optical switch 1 of the present embodiment, the polarity of the voltage applied to the translucent piezoelectric actuators 11 and 12 is changed to change from the first optical path state to the second optical path state or from the second optical path state. It is possible to easily switch to the first optical path state. At the time of switching the optical path state, the translucent piezoelectric actuators 11 and 12 themselves have a built-in light transmission path. In other words, another optical member is driven by the translucent piezoelectric actuators 11 and 12 to change the optical path. Since there is no need to change, significant downsizing can be promoted. Further, since it is not necessary to drive other optical members, the structure of the optical switch 1 can be simplified.

  In addition, when another optical member is driven by a piezoelectric actuator, the response speed tends to be lower than the response speed of the piezoelectric actuator itself because the other optical member must be physically driven. On the other hand, in this embodiment, since the translucent piezoelectric actuators 11 and 12 themselves, which are piezoelectric actuators, are displaced and the optical path is changed, the response speed is also improved.

  In the conventional electrostatic optical switch, not only the response speed is slow as 1 to 10 μs, but also the driving voltage is as high as several tens of volts. On the other hand, in the optical switch 1 of the present embodiment, the response speed is as extremely fast as 0.02 to 0.1 μsec. Further, since the translucent piezoelectric actuators 11 and 12 are made of the laminated piezoelectric material, they can be driven with an extremely low voltage of several volts.

  Therefore, according to the present embodiment, it is possible to provide the optical switch 1 that is small in size, can be configured inexpensively, and has an excellent response speed.

  FIG. 4 is a schematic plan view showing a modification of the optical switch 1 of the above embodiment. In the optical switch 21 shown in FIG. 4, the translucent piezoelectric actuator 11 is fixed only on the first fixing member 2 side, and the translucent piezoelectric actuator is not provided on the second fixing member 3 side. That is, the light-transmitting adhesive film 14 is directly laminated on the flat portion 9c of the fixing portion 9 made of a light-transmitting material such as quartz. Thus, in this invention, the translucent piezoelectric actuator may be provided only in the 1st fixing member.

  In FIGS. 1 and 4, the translucent adhesive films 13 and 14 are provided. However, the translucent adhesive films 13 and 14 may not be used. In that case, the first plane and the second plane are constituted by the main surface 15d of the translucent piezoelectric actuator 11 and the outer main surface of the translucent piezoelectric actuator 12 of FIG. Further, in the second fixing member 3 shown in FIG. 4, the plane portion 9 c constitutes the “second plane” described above.

  However, preferably, by using the light-transmitting adhesive films 13 and 14 as described above, the second and first fixing members from the first and second fixing members are not leaked and scattered without being leaked or scattered. It can be moved straight to the fixed member side, which is desirable.

  FIG. 5 is a schematic plan view showing a multi-channel optical switch as a second embodiment of the present invention. In the multi-channel optical switch 31, a plurality of optical switches 1 according to the first embodiment are connected in series and in parallel. Thus, a multi-channel type optical switch can be configured according to the present invention by connecting a plurality of optical switches 1 in series and / or in parallel. In this case, since each optical switch 1 is small in size and excellent in response speed, the multi-channel optical switch 31 configured using a large number of optical switches 1 is also expected to be downsized and improved in response speed. can do.

As the light-transmitting ceramic material constituting the light transmitting piezoelectric actuator as described above can be exemplified by the composition with the addition of La ₂ O ₃ in Pb (Zr, Ti) solid solution.

Next, a specific experimental example of a method for manufacturing a laminated piezoelectric body for obtaining the translucent piezoelectric actuator will be described. First, a ceramic slurry was obtained by using ceramic powder having a composition in which La ₂ O ₃ was added to the Pb (Zr, Ti) -based solid solution described above. A ceramic green sheet having a thickness of 10 μm was prepared using this ceramic slurry. Then, a Pt paste was printed on the ceramic green sheet, and an internal electrode pattern was printed. In printing the internal electrode pattern, a Pt paste was printed so that the window B was formed. Next, a plurality of ceramic green sheets on which the internal electrode paste was printed were laminated, plain ceramic green sheets were laminated on the top and bottom, and pressed by a cold isostatic press to obtain a laminate.

The laminate was fired in an O ₂ and PbO atmosphere to obtain a piezoelectric body that was transparent except for the internal electrodes. Next, a pair of external electrodes 17 and 18 were formed to obtain a laminated piezoelectric body 15.

  Then, stress is applied in a direction connecting the surfaces on which the external electrodes 17 and 18 of the multilayer piezoelectric body 15 are formed, that is, in a direction parallel to the internal electrodes, and heat treatment is performed at 500 ° C. for 120 minutes, and 1 ° C./minute. It was gradually cooled from 500 ° C. to 200 ° C. at the following temperature drop rate. In this slow cooling, for comparison, a piezoelectric body that was heat-treated without applying the stress and a piezoelectric body that was not subjected to the stress and not subjected to the heat treatment were separately prepared.

  The crystal structure of the piezoelectric body heat-treated and slowly cooled under the stress and the piezoelectric body not subjected to the heat treatment and stress were examined by X-ray diffraction.

  Thereafter, electrodes were provided on both principal surfaces of the piezoelectric body that had been subjected to heat treatment and slow cooling under stress, and a high voltage was applied for polarization. Next, a high voltage was applied to the external electrodes 17 and 18 connected to the first and second internal electrodes to polarize them. The polarization electrodes on both main surfaces were removed after polarization. Thus, the translucent piezoelectric actuator 11 was produced. As a comparative example, the piezoelectric body having a history of heat treatment and no stress applied thereto was similarly subjected to polarization treatment, and a translucent piezoelectric actuator was manufactured.

  As a result of X-ray diffraction, the piezoelectric body obtained by heat treatment under stress for 120 minutes at 500 ° C. and slow cooling was greatly oriented in the (001) plane as shown in FIG. On the other hand, it is understood that the orientation of the (001) plane is small in the piezoelectric body prepared for comparison without stress and heat treatment. When the degree of orientation on the (001) plane is set to (001) = (001) / {(001) + (100)} × 100 (%), the piezoelectric body that has been heat-treated and gradually cooled to the 001 plane. The degree of orientation was 53%, and the piezoelectric material prepared for comparison was only 41%.

  Moreover, when the piezoelectric body heat-treated under stress and annealed slowly was compared with the piezoelectric body heat-treated without applying stress, the degree of orientation to the (001) plane was determined by heat-treating under stress and annealing. The piezoelectric body was 60%, and the piezoelectric body heat-treated without applying stress was 52%.

  Therefore, it can be seen that by using the piezoelectric body heat-treated under stress as described above, the translucent piezoelectric actuators 11 and 12 can be driven at a lower voltage and a large displacement can be obtained reliably.

  Next, the translucency of the piezoelectric body heat-treated under stress as described above and the piezoelectric body not heat-treated under stress were measured. As a result, the transmissivity of the piezoelectric body 15 that was not heat-treated under stress was 63%, whereas the translucency of the piezoelectric body 15 that was heat-treated under the stress was 70%, and the translucency was also high. 7% increase. Therefore, it can be seen that the light propagation loss in the translucent piezoelectric actuator can also be reduced.

(A) And (b) is front sectional drawing which shows the top view of the optical switch which concerns on the 1st Embodiment of this invention, and the translucent piezoelectric actuator and translucent adhesion film which are used for this optical switch. (A) And (b) is each plane sectional drawing of the translucent piezoelectric actuator used in the 1st Embodiment of this invention. The top view which shows the optical switch of 1st Embodiment when it exists in a 1st optical path state. The top view which shows the modification of the optical switch of 1st Embodiment. FIG. 5 is a schematic plan view showing a multi-channel optical switch as a second embodiment of the present invention. The figure which shows the X-ray-diffraction result of the piezoelectric material to which heat processing was performed again, and the piezoelectric material which has not been heat-processed again. The perspective view for demonstrating an example of the conventional optical switch. The schematic plan view for demonstrating the other example of the conventional optical switch.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Optical switch 2 ... 1st fixing member 3 ... 2nd fixing member 4 ... 1st optical fiber (1st optical propagation path)
5 ... Second optical fiber (second optical propagation path)
6 ... Third optical fiber (third optical propagation path)
7: Fourth optical fiber (fourth optical propagation path)
DESCRIPTION OF SYMBOLS 8 ... Fixed part 8a, 8b ... Inclined surface 8c ... Flat surface part 9 ... Fixed part 9a, 9b ... Inclined surface 9c ... Flat surface part 11, 12 ... 1st, 2nd translucent piezoelectric actuator 13, 14 ... Translucent Adhesion film 13a ... first plane 14a ... second plane 15 ... piezoelectric bodies 15a, 15b ... end faces 15c, 15d ... main surfaces 16a-16h ... internal electrodes 17, 18 ... external electrodes B ... window

Claims (8)

An optical switch capable of propagating light incident from a first optical propagation path to a second optical propagation path or a third optical propagation path,
The first light propagation path and the second light propagation path are fixed, and provided so that the light incident from the first light propagation path can be reflected and guided to the second light propagation path A first fixing member having a first plane as a reflective surface;
The third light propagation path is fixed, and the light incident from the first light propagation path is not reflected by the first plane, but is incident when the light propagates beyond the first plane. A second fixing member configured to have a second plane as an incident surface and configured to guide light incident from the second plane to the third light propagation path;
The first fixing member includes a translucent piezoelectric actuator that expands and contracts due to a piezoelectric effect depending on whether or not a voltage is applied, and the translucent piezoelectric actuator transmits light incident from a first light propagation path. An optical transmission path for propagating to the first plane; and an optical transmission path for guiding the light reflected by the first plane to the second optical propagation path. And the first optical path state in which the light is reflected by the first plane and the first plane is in close contact with the second plane of the second fixing member. An optical switch configured to be able to assume a second optical path state in which light is not reflected by the first plane and is guided to a third optical propagation path.   A second translucent piezoelectric actuator is disposed on the second fixing member, and the second translucent piezoelectric actuator receives light incident in the second optical path state from the second plane. The optical switch according to claim 1, further comprising an optical transmission path that leads to a third optical propagation path.   When the fourth light propagation path is fixed to the second fixing member and is in the first optical path state, the light incident from the fourth light propagation path is the second fixing member. When reflected in the second plane and guided to the third optical propagation path and in the second optical path state, the light incident from the fourth optical propagation path is the second plane and the first optical path. The optical switch according to claim 1, wherein the optical switch is configured to be guided to the second optical propagation path through the first plane of the fixing member.   A second translucent piezoelectric actuator is disposed on the second fixing member, and the second translucent piezoelectric actuator transmits light incident from a fourth light propagation path to the second plane. The optical switch according to claim 3, further comprising: a light transmission path that guides light guided to the third light propagation path from the second plane in the second optical path state.   The translucent piezoelectric actuator includes a piezoelectric body having a pair of opposing main surfaces, and a plurality of internal electrodes arranged so as to overlap with each other via the piezoelectric layer between the pair of main surfaces of the piezoelectric body. A laminated piezoelectric body having at least a part of the plurality of internal electrodes formed with windows for forming the plurality of light transmission paths. The optical switch according to claim 1, wherein:   A translucent material made of a material having excellent adhesion to the second plane of the second fixing member on one surface of the translucent piezoelectric actuator provided on the first fixing member. The optical switch according to claim 1, wherein an adhesive film is formed, and an outer surface of the translucent adhesive film is the first plane.   A translucent material made of a material having better adhesion to the first plane of the first fixing member than the translucent piezoelectric actuator on the surface of the second fixing member facing the first plane. The optical switch according to any one of claims 1 to 6, wherein an adhesive film is formed, and an outer surface of the translucent adhesive film is the second plane. A multi-channel optical switch comprising a plurality of the optical switches according to claim 1, wherein the plurality of optical switches are connected in series and / or in parallel.

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