Abstract:
Disclosed herewith is an optical switch provided on an optical path of an optical waveguide and which switches an advancing direction of a light passed through the optical path. The optical switch includes a movable switching member which switches the advancing direction of the light, and a driving member which electrostatically drives said switching member to move in an arbitrary position so that the light passed through the optical path is guided to different directions.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
         [0001]    This application is based on Japanese Patent Application No. 2002-30707 filed in Japan on Feb. 7, 2002, the entire content of which is hereby incorporated by reference.  
         BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates to an optical switch device which is provided on an optical path of an optical waveguide and switches an advancing direction of an incident light to the optical waveguide.  
           [0004]    2. Description of the Related Art  
           [0005]    In recent years, an optical network is developed for transmitting mass information, and an optical switch as device for dividing a light is used for the optical network. A conventional optical switch switches a light between linear advancing and reflection in such a manner that a micromirror provided on an optical path of a light flux emitted from an optical fiber is supported by a movable plate and the movable plate is moved by applying a voltage so that the micromirror is retracted from the optical path. However, such an optical switch additionally requires a movable plate for moving a micromirror.  
           [0006]    In addition, there has been conventionally suggested an optical switch in which a groove section which slantly crosses two crossing optical waveguides is provided, air bubbles are formed in a liquid filling the groove section and the air bubbles are heated by a microheater so as to be moved. According to this optical switch, since a refractive index of the filling liquid and a refractive index of the optical waveguides are set to be approximately equal with each other, when the liquid is provided onto the optical paths of the optical waveguides, a light advances straight, and when air bubbles are provided, a light is reflected so that the advancing direction is switched. However, since such an optical switch carries out heating, it requires a microheater and a heat radiating mechanism.  
           [0007]    Besides the above-mentioned optical switches, there is an optical switch which uses a micropump having piezoelectric element or a magnetic force of a magnetic coil in order to drive a mirror or a filter provided on a crossed section of two optical waveguides. However, in a driving mechanism such as a micropump which utilizes a liquid, it is difficult to stop a filter on a predetermined position and its locating mechanism becomes complicated. Moreover, in the case where an electromagnetic force of a coil or the like is used, a driving force generating section including the coil for driving a filter becomes complicated and thus becomes large. Therefore, in those conventional optical switches, there arises a problem that their structure becomes complicated.  
           [0008]    Further, in recent years, so-called wavelength multiplex communication is carried out. With this wavelength multiplex communication, different pieces of information are placed on lights (carrier waves) with different wavelengths and a plurality of carrier waves are superposed so that mass information can be transmitted by one optical fiber. However, according to the above-mentioned conventional optical switch, since the lights where wavelengths are multiplexed are reflected or transmitted uniformly, pieces of information placed on the carrier waves cannot be output separately. For this reason, since the pieces of information are branched by an additional branching filter or the like so as to be taken out, there arises a problem that an optical communication system having an optical switch becomes complicated.  
         SUMMARY OF THE INVENTION  
         [0009]    It is a main object of the present invention to provide an optical switch which is capable of separately outputting lights where wavelengths are multiplexed.  
           [0010]    It is another object of the present invention to provide an optical switch with a simple structure.  
           [0011]    The above objects of the present invention is achieved by providing an optical switch provided on an optical path of an optical waveguide and which switches an advancing direction of a light passed through the optical path of the optical waveguide. The optical switch comprises a movable switching member which switches the advancing direction of the light; and a driving member which electrostatically drives said switching member to move in an arbitrary position so that the light passed through the optical path of the optical waveguide is guided to different directions.  
           [0012]    These and other objects, features and advantages of the present invention will become apparent from the following description of the preferred embodiments when the same is read in conjunction with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0013]    These and other objects, advantages and features of the present invention will become apparent from the following description thereof taken in conjunction with the accompanying drawings in which:  
         [0014]    FIGS.  1 ( a ),  1 ( b ),  1 ( c ) and  1 ( d ) are side sectional views respectively showing a method of manufacturing a waveguide in a main body of an optical switch according to the present invention;  
         [0015]    [0015]FIG. 2 is an outline perspective view showing a structure of an optical switch  1  according to a first embodiment of the present invention;  
         [0016]    [0016]FIG. 3 is a side sectional view showing a structure of a periphery of a groove section in the optical switch  1 ;  
         [0017]    [0017]FIG. 4 is a diagram showing transmittance of an interference filter  3   a  of the optical switch  1 ;  
         [0018]    [0018]FIG. 5 is a diagram showing transmittance of an interference filter  3   b  of the optical switch  1 ;  
         [0019]    [0019]FIG. 6 is a diagram showing transmittance of an interference filter  3   c  of the optical switch  1 ;  
         [0020]    FIGS.  7 ( a ),  7 ( b ),  7 ( c ) and  7 ( d ) are respectively diagrams showing a relationship between a moving element section and electrodes of each filter when each filter moves;  
         [0021]    FIGS.  8 ( a ),  8 (i b),  8 ( c ) and  8 ( d ) are diagrams respectively showing a relationship between the moving element section and the electrodes of each filter when each filter moves;  
         [0022]    FIGS.  9 ( a ),  9 ( b ),  9 ( c ) and  9 ( d ) are diagrams respectively showing a relationship between the moving element section and the electrodes of each filter when each filter moves;  
         [0023]    [0023]FIG. 10 is a plan view showing a state of the optical switch  1  in an initial state (total transmitting mode);  
         [0024]    [0024]FIG. 11 is a plan view showing a state of the optical switch  1  in a total reflection mode;  
         [0025]    [0025]FIG. 12 is a plan view showing a state that the optical switch  1  allows a wavelength λ1 to transmit;  
         [0026]    [0026]FIG. 13 is a plan view showing a state that the optical switch  1  allows a wavelength λ2 to transmit;  
         [0027]    [0027]FIG. 14 is a diagram showing transmittance of another interference filter provided to the optical switch  1  according to the first embodiment of the present invention;  
         [0028]    [0028]FIG. 15 is an exploded sectional view showing a structure of a periphery of a groove section in an optical switch la according to a second embodiment of the present invention;  
         [0029]    [0029]FIG. 16 is a side sectional view showing a structure of a periphery of a groove section in the optical switch  1   a;    
         [0030]    [0030]FIG. 17 is an exploded sectional view showing a structure of a periphery of a groove section in an optical switch  1   b  according to a third embodiment of the present invention;  
         [0031]    [0031]FIG. 18 is a side sectional view showing a structure of the periphery of the groove section in the optical switch  1   b;    
         [0032]    [0032]FIG. 19 is an exploded sectional view showing a structure of a periphery of a groove section in an optical switch  1   c  according to a fourth embodiment of the present invention;  
         [0033]    [0033]FIG. 20 is side sectional view showing a structure of the periphery of the groove section in the optical switch  1   c;    
         [0034]    [0034]FIG. 21 is an outline perspective view showing a structure of a filter in the optical switch  1   c;    
         [0035]    [0035]FIG. 22 is a diagram showing a relationship between stator and three-phase wiring section;  
         [0036]    [0036]FIG. 23 is a diagram showing a relationship between stator and three-phase wiring section; and  
         [0037]    [0037]FIG. 24 is a plan view showing an optical switch line provided with a plurality of optical switches. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0038]    There will be explained below an optical switch device according to embodiments of the present invention with reference to the attached drawings.  
         [0039]    Firstly, there will be simply explained below a method of manufacturing a waveguide in a main body of an optical switch to be used commonly in the following embodiments. It is noted that FIGS.  1 ( a ) through  1 ( d ) are sectional views of the main body of the optical switch and show the sectionals in a direction which crosses two waveguides provided in the main body.  
         [0040]    As shown in FIG. 1( a ), a lower clad layer  11  made of quartz or the like is deposited on a substrate  10  made of Si or the like by chemical vapor deposition (CVD) or the like. As shown in FIG. 1( b ), a core layer  12  made of quartz or the like is deposited on the lower clad layer  11 . Refractive index of the lower clad layer  11  is smaller than that of the core layer  12  by doping fluorine. A resist  13  is applied to the core layer  12  by the spin coat process or the like and is exposed or developed so as to be patterned into a predetermined shape.  
         [0041]    Next, as shown in FIG. 1( c ), the core layer  12  is etched by reactive ion etching (RIE) or the like, so that a waveguide  14  with a predetermined shape is formed. In the case where the core layer  12  is made of quartz, CHF3, CF4 or the like is used as a reactive gas of RIE. After the resist  13  is peeled, as shown in FIG. 1( d ) an upper clad layer  15  made of the same material as that of the lower clad layer  11  is deposited while fluorine or the like is being doped. As a result, a main body  8 , which waveguides an incident light by means of the waveguide  14  sandwiched between the lower clad layer  11  with smaller refractive index and the upper clad layer  15 , can be obtained.  
         [0042]    There will be explained below respective embodiments of the optical switch composed of the main body  8  having the waveguide  14  manufactured by such a method. In the respective embodiments, the waveguide  14  provided to the main body  8  has the common structure.  
         [0043]    &lt;First Embodiment&gt; 
         [0044]    [0044]FIG. 2 is an outline perspective view showing a structure of an optical switch  1  according to the first embodiment of the present invention. In the optical switch  1 , two waveguides  14   a  and  14   b  are provided to the main body  8  so as to cross at a predetermined crossing angle θ by the above-mentioned manufacturing method. A groove section  2  is formed so as to cross a crossed section  14   c  of the waveguides  14   a  and  14   b . A filter  3  is put into the groove section  2 . The filter  3  has interference filters  3   a  through  3   c  with different optical properties, and a moving element section  3   d  formed by a resistor material having a predetermined resistance value (for example, 10 10  Ω/□ to 10 16    106  /□ , it is noted that Ω/□ is a unit representing surface resistivity). The groove section  2  is provided with the filter  3 . A plurality of electrodes  4  which function as stators with respect to the moving element section  3   d  are provided to the main body  8  so as to drive the filter  3  along the groove section  2 . A three-phase wiring section  5  for applying a three-phase driving voltage is provided to the plural electrodes  4 . It is noted that the plural electrodes  4  are covered with an insulating film  7  as mentioned later, but in order to simplify the explanation, it is not shown in FIG. 2.  
         [0045]    [0045]FIG. 3 is a sectional view of the switch  1  of FIG. 2. The electrode  4 , which is provided by patterning a metal film such as an aluminum film on a surface of the main body  8 , extends to a side surface of the groove section  2 . The electrode  4  is provided so as to be opposed to a side surface  3   x  of the filter  3 . In order to insulating the electrode  4  from the filter  3 , insulating matching oil  6  such as silicone oil is sealed into the groove section  2 . The insulating film  7  is provided onto the surface of the main body  8  so as to cover the electrodes  4 .  
         [0046]    Since the electrodes  4  are formed by metal, when they are provided so as to be overlapped with the waveguides  14   a  and  14   b , a light is attenuated. Therefore, as shown in FIG. 2, in the main body  8 , the electrodes  4  are provided onto portions different from the portion provided with the waveguides  14   a  and  14   b  so as to be opposed to the moving element section  3   d  of the filter  3 . The electrodes  4  are metal films with thickness of 1000 Å and width of 5 μm, for example, and gaps between the electrodes are 5 μm.  
         [0047]    In the filter  3 , the interference filters  3   a  through  3   c  have optical properties shown in FIGS. 4 through 6, for example. A light with wavelength λ1(=1.3 μm=1300 nm) and a light with wavelength λ2(=1.55 μm=1550 nm) are wavelength-multiplexed into one optical fiber by a fiber coupler, and a light flux which enters the optical switch  1  enters from an input port I (see FIG. 2).  
         [0048]    Next, there will be explained below a driving method of the filter  3  when the electrodes  4  are provided in the above manner with reference to FIGS. 7 through 13. It is noted that as for the electrodes  4 , as shown in FIGS. 7 through 9, the electrodes  4   a  through  4   i  are provided, the electrodes  4   a ,  4   d  and  4   g  are connected with a wiring  5   a  of the three-phase wiring section  5 , the electrodes  4   b ,  4   e  and  4   h  are connected with a wiring  5   b , and the electrodes  4   c ,  4   f  and  4   i  are connected with a wiring  5   c . When the optical switch  1  is in an initial state (total transmitting mode), as shown in FIG. 10, all the interference filters  3   a  through  3   c  of the filter  3  are retracted from the crossed section  14   c  of the waveguides  14   a  and  14   b . The widths between the electrodes  4  and the widths of the interference filters  3   a  through  3   c  are equal. It is noted that in order to simplify the explanation, the matching oil  6  and the insulating film  7  are not shown in FIGS. 10 through 13.  
         [0049]    In the initial state shown in FIG. 10, the lights with wavelengths λ1 and λ2 which enter from the input port  1  directly advance in the waveguide  14   a  and are output from a first output port Oa. At this time, as shown in FIG. 7( a ), a positive voltage +V is applied to the wiring  5   a , a negative voltage −V is applied to the wiring  5   b  and a ground voltage is applied to the wiring  5   c . As a result, the electrodes  4   a ,  4   d  and  4   g  are charged with positive polarity, and the electrodes  4   b ,  4   e  and  4   h  are charged with negative polarity. At this time, in the moving element section  3   d  of the filter  3  opposed to the electrodes  4   a  through  4   i , portions  3   p ,  3   r  and  3   t  opposed to the electrodes  4   a ,  4   d  and  4   g  are charged with negative polarity, and portions  3   q ,  3   s  and  3   u  opposed to the electrodes  4   b ,  4   e  and  4   h  are charged with positive polarity.  
         [0050]    When the filter  3  is moved from the initial state in FIG. 10 and the interference filter  3   a  of the filter  3  is arranged on the crossed section  14   c  of the waveguides  14   a  and  14   b  (total reflection mode) as shown in FIG. 11, a voltage to be applied to the three-phase wiring section  5  is switched so that a negative voltage −V is applied to the wirings  5   a  and  5   c  and a positive voltage +V is applied to the wiring  5   b  as shown in FIG. 7( b ). At this time, the moving of electric charges accumulated on the portions  3   p  through  3   u  is disturbed by high resistance so as to be stopped in the moving element section  3   d  of the filter  3 .  
         [0051]    At this time, a repulsive force acts upon the portions  3   p ,  3   r  and  3   t  due to the electrodes  4   a ,  4   c ,  4   d ,  4   f  and  4   g  charged with negative polarity, and simultaneously an attracting force acts thereon due to the electrodes  4   b ,  4   e  and  4   h  charged with positive polarity. Similarly, a repulsive force acts upon the portions  3   q ,  3   s  and  3   u  due to the electrodes  4   b ,  4   e  and  4   h  charged with positive polarity, and simultaneously an attracting force acts thereon due to the electrodes  4   c ,  4   f  and  4   i  charged with negative polarity. As a result, a repulsive force acts upon the filter  3  to a vertical direction of FIG. 7, and a driving force is generated to the left side, so that the filter  3  moves by one width of the electrodes  4 . As a result, the portions  3   p ,  3   r  and  3   t  are opposed to the electrodes  4   b ,  4   e , and  4   h  charged with positive polarity, and the portions  3   q ,  3   s  and  3   u  are opposed to the electrodes  4   c ,  4   f  and  4   i  charged with negative polarity.  
         [0052]    A ground voltage is applied to the wiring  5 a, a positive voltage +V is applied to the wiring  5   b  and a negative voltage −V is applied to the wiring  5   c  as shown in FIG. 7( c ), and the position of the filter  3  is fixed so that the interference filter  3   a  of the filter  3  is arranged on the crossed section  14   c  of the waveguides  14   a  and  14   b  as shown in FIG. 11. The transmittance of the interference filter  3   a  is approximately 0% at the wavelengths λ1 and λ2 (see FIG. 4). Therefore, the lights with wavelengths λ1 and λ2 which have entered from the input port I are reflected by the interference filter  3   a  of the filter  3  so as to advance in the waveguide  14   b  and output from a second output port Ob.  
         [0053]    In the case where the interference filter  3   b  of the filter  3  is arranged on the crossed section  14   c  of the waveguides  14   a  and  14   b  as shown in FIG. 12 from the state in FIG. 11, a voltage to be applied to the three-phase wiring section  5  is switched so that a negative voltage −V is applied to the wirings  5   a  and  5   b  and a positive voltage +V is applied to the wiring  5   c  as shown in FIG. 7( d ). At this time, similarly to the time when the position of the interference filter  3  is changed from the state in FIG. 10 into the state in FIG. 11, a repulsive force acts upon the filter  3  to the vertical direction of FIG. 7 and a driving force is generated to the left side. As a result, the filter  3  moves by one width of the electrodes  4 , and the portions  3   p ,  3   r  and  3   t  are opposed to the electrodes  4   c ,  4   f  and  4   i  charged with positive polarity and the portions  3   q  and  3   s  are opposed to the electrodes  4   d  and  4   g  charged with negative polarity in the moving element section  3   d.    
         [0054]    A negative voltage −V is applied to the wiring  5   a , a ground voltage is applied to the wiring  5   b  and a positive voltage +V is applied to the wiring  5   c  as shown in FIG. 8( a ), and the position of the filter  3  is fixed so that the interference filter  3   b  of the filter  3  is arranged on the crossed section  14   c  of the waveguides  14   a  and  14   b . At this time, the transmittance of the interference filter  3   b  is approximately 100% at the wavelength λ1, and the transmittance is approximately 0% at the wavelength λ2 (see FIG. 5). For this reason, the light with wavelength λ1 which has entered from the input port I transmits through the filter  3  so as to linearly advance in the waveguide  14   a  and output from the first output port Oa. Moreover, the light with wavelength λ2 is reflected by the interference filter  3   b  of the filter  3  so as to linearly advance in the waveguide  14   b  and output from the second output port Ob.  
         [0055]    Further, when the interference filter  3   c  of the filter  3  is arranged on the crossed section  14   c  of the waveguides  14   a  and  14   b  as shown in FIG. 13 from the state in FIG. 12, a voltage to be applied to the three-phase wiring section  5  is switched so that a positive voltage +V is applied to the wiring  5   a  and a negative voltage −V is applied to the wirings  5   b  and  5   c  as shown in FIG. 8( b ). As a result, the filter  3  moves by one width of the electrodes  4 , and the portions  3   p  and  3   r  are opposed to the electrodes  4   d  and  4   g  charged with positive polarity, and the portions  3   q  and  3   s  are opposed to the electrodes  4   e  and  4   h  charged with negative polarity.  
         [0056]    A positive voltage +V is applied to the wiring  5   a , a negative voltage −V is applied to the wiring  5   b  and a ground voltage is applied to the wiring  5   c  as shown in FIG. 8( c ), and the position of the filter  3  is fixed so that the interference filter  3   c  of the filter  3  is arranged on the crossed section  14   c  of the waveguides  14   a  and  14   b  as shown in FIG. 13. The transmittance of the interference filter  3   c  is approximately 0% at wavelength λ1, and the transmittance is approximately 100% at wavelength λ2 (see FIG. 6). For this reason, the light with wavelength λ1 which has entered from the input port I is reflected by the interference filter  3   c  of the filter  3  so as to linearly advance in the waveguide  14   b  and output from the second output port Ob. Meanwhile, the light with wavelength λ2 transmits through the interference filter  3   c  of the filter  3  so as to linearly advance in the waveguide  14   a  and output from the first output port Oa.  
         [0057]    On the contrary, when the state is changed from the state in FIG. 13 into the state in FIG. 12, a voltage to be applied to the three-phase wiring section  5  is switched so that a negative voltage −V is applied to the wiring  5   a  and a positive voltage +V is applied to the wirings  5   b  and  5   c  as shown in FIG. 8( d ). At this time, a repulsive force acts upon the portions  3   p ,  3   r  and  3   t  due to the electrodes  4   d  and  4   g  charged with negative polarity, and an attracting force acts thereon due to the electrodes  4   c ,  4   f  and  4   i  charged with positive polarity. Similarly, a repulsive force acts upon the portions  3   q  and  3   s  due to the electrodes  4   e ,  4   f ,  4   h  and  4   i  charged with positive polarity, and simultaneously an attracting force acts thereon due to the electrodes  4   d  and  4   g  charged with negative polarity.  
         [0058]    As a result, a repulsive force acts upon the filter  3  to the vertical direction in FIG. 8, and a driving force is generated to the right side, so that the filter  3  moves by one width of the electrodes  4 . As a result, the portions  3   p ,  3   r  and  3   t  are opposed to the electrodes  4   c ,  4   f  and  4   i  charged with positive polarity, and the portions  3   q  and  3   s  are opposed to the electrodes  4   d  and  4   g  charged with negative polarity. A negative voltage −V is applied to the wiring  5   a , a ground voltage is applied to the wiring  5   b  and a positive voltage +v is applied to the wiring  5   c  as shown in FIG. 9( a ), and the position of the filter  3  is fixed so that and the interference filter  3   b  of the filter  3  is arranged on the crossed section  14   c  of the waveguides  14   a  and  14   b  as shown in FIG. 12.  
         [0059]    When the state is switched from the state in FIG. 12 into the state in FIG. 11, a voltage to be applied to the three-phase wiring section  5  is switched so that a positive voltage +V is applied to the wirings  5   a  and  5   b  and a negative voltage −V is applied to the wiring  5   c  as shown in FIG. 9( b ). As a result, a repulsive force acts upon the filter  3  to the vertical direction in FIG. 9 and a driving force is generated to the right side, so that the filter  3  moves by one width of the electrodes  4 . A ground voltage is applied to the wiring  5   a , a positive voltage +V is applied to the wiring  5   b  and a negative voltage −V is applied to the wiring  5   c  as shown in FIG. 9( c ), and the position of the filter  3  is fixed so that the interference filter  3   a  of the filter  3  is arranged on the crossed section  14   c  of the guide waves  14   a  and  14   b  as shown in FIG. 11.  
         [0060]    When the state is changed from the state in FIG. 11 into the state in FIG. 10, a voltage to be applied to the three-phase wiring section  5  is switched so that a positive voltage +V is applied to the wirings  5   a  and  5   c  and a negative voltage −V is applied to the wiring  5   b  as shown in FIG. 9( d ). As a result, a repulsive force acts upon the filter  3  to the vertical direction in FIG. 9 and a driving force is generated to the right side, so that the filter  3  moves by one width of the electrodes  4 . Again a positive voltage +V is applied to the wiring  5   a , a negative voltage −V is applied to the wiring  5   b  and a ground voltage is applied to the wiring  5   c  as shown in FIG. 7( a ), and the filter  3  is arranged in a position where all the interference filters  3   a  through  3   c  are retracted from the crossed section  14   c  of the waveguides  14   a  and  14   b  as shown in FIG. 10.  
         [0061]    When the interference filters  3   a  through  3   c  of the filter  3  are moved one by one by performing the above operations, a voltage to be applied to the three-phase wiring section  5  is switched in the order of FIG. 7( b ), FIG. 7( d ) and FIG. 8( a ), so that the state can be changed from the state in FIG. 10 into the state in FIG. 12. Moreover, a voltage to be applied to the three-phase wiring section  5  is switched in the order of FIG. 7( b ), FIG. 7( d ), FIG. 8( b ) and FIG. 8( c ), so that the state can be changed from the state in FIG. 10 into the state in FIG. 13. Further, a voltage to be applied to the three-phase wiring section  5  is switched in the order of FIG. 7( d ), FIG. 8( b ) and FIG. 8( c ), so that the state can be changed from the state in FIG. 11 into the state in FIG. 13.  
         [0062]    On the contrary, a voltage to be applied to the three-phase wiring section  5  is switched in the order of FIG. 8( d ), FIG. 9( b ) and FIG. 9( c ), so that the state can be changed from the state in FIG. 13 into the state in FIG. 11. Moreover, a voltage to be applied to the three-phase wiring section  5  is switched in the order of FIG. 8( d ), FIG. 9( b ),  9 ( d ) and FIG. 7( a ), so that the state can be changed from the state in FIG. 13 into the state in FIG. 10. Further, a voltage to be applied to the three-phase wiring section  5  is switched in the order of FIG. 9( b ), FIG. 9( d ) and FIG. 7( a ), so that the state can be changed from the state in FIG. 12 into the state in FIG. 10.  
         [0063]    Therefore, an inductive charge type electrostatic system by means of the electrodes  4  and the moving element section  3   d  of the filter  3  is utilized so as to move the filter  3 , so that a wavelength multiplexed light flux where carrier waves with plural wavelengths are superposed can be switched among total reflection, total transmission, partial transmission and partial reflection. Moreover, as shown in FIG. 14, the interference filter can be set as a narrow band which allows only a light with wavelength of 1.55 μm (1550 nm) to transmit through, for example.  
         [0064]    According to the present embodiment, since wavelength multiplexed incident lights can be output separately by switching per wavelength, an additional branching filter or the like is not required thereby simplifying an optical communication system.  
         [0065]    &lt;Second Embodiment&gt; 
         [0066]    [0066]FIG. 15 is an exploded perspective view showing a structure of an optical switch  1   a  according to a second embodiment of the present invention. Similarly to the first embodiment, in the optical switch  1   a , a main body  8  is formed with two waveguides  14   a  and  14   b , and a groove section  2  which crosses a crossed section  14   c  of the waveguides  14   a  and  14   b . A filter  3  is put into the groove section  2  into which matching oil  6  such as silicone oil has been sealed.  
         [0067]    Further, a rear surface of a cover section  20  covering an upper surface of the main body  8  via an insulating film  27  is provided with a plurality of electrodes  24  which function as stators for a moving element section  3   d , and a three-phase wiring section  25  which applies a three-phase driving voltage to the plural electrodes  24 . It is noted that the cover section  20  is shown in a transmitted form in order to show a relationship between the electrodes  24  and the three-phase wiring section  25 . The electrodes  24  are provided on positions which cross the moving element section  3   d  of the filter  3 . The electrodes  24  are made of metal films with thickness of 1000 Å and width of 5 μm, for example, similarly to the first embodiment, and gaps between the electrodes are 5 μm.  
         [0068]    [0068]FIG. 16 is a sectional view of the optical switch  1   a . The electrodes  24  are opposed to an upper surface  3   y  of the filter  3  put into the groove section  2  via the matching oil  6  and the insulating film  27 . Since the operation of the optical switch  1   a  having such a structure is similar to that of the first embodiment, the explanation thereof is omitted.  
         [0069]    &lt;Third Embodiment&gt; 
         [0070]    [0070]FIG. 17 is an exploded perspective view showing a structure of an optical switch  1   b  according to a third embodiment of the present invention. In the optical switch  1   b  of the present embodiment, after a surface of a substrate  30  is provided with a plurality of electrodes  34  which function as stators and a three-phase wiring section  35  which applies a three-phase driving voltage to the plural electrodes  34 , an insulating film  37  is provided thereon so as to cover the upper surface. A clad layer  31  having waveguides  14   a  and  14   b  are provided on the upper surface of the insulating film  37  so that a groove section  2  which crosses a crossed section  14   c  of the two waveguides  14   a  and  14   b  is formed.  
         [0071]    A filter  3  is put into the groove section  2  into which matching oil  6  such as silicone oil has been sealed. The electrodes  34  are provided on positions which cross a moving element section  3   d  of the filter  3 . Moreover, the electrodes  34  are made of metal films with thickness of 1000 Å and width of 5 μm, for example, similarly to the first embodiment, and gaps between the electrodes are 5 μm.  
         [0072]    [0072]FIG. 18 is a sectional view of the optical switch  1   b . The electrodes  34  are opposed to a lower surface  3   z  of the filter  3 , which is put into the groove section  2 , via the matching oil  6  and the insulating film  37 . Since the operation of the optical switch  1   b  having such a structure is similar to that of the first embodiment, the explanation thereof is omitted.  
         [0073]    &lt;Fourth Embodiment&gt; 
         [0074]    [0074]FIG. 19 is an exploded perspective view showing an internal structure of an optical switch  1   c  according to a fourth embodiment of the present invention. Similarly to the second embodiment, in the optical switch  1   c , a main body  8  is formed with two waveguides  14   a  and  14   b , and a groove section  2  which crosses a crossed section  14   c  of the waveguides  14   a  and  14   b . A filter  43  is put into the groove section  2  into which matching oil  6  has been sealed, and a portion provided with interference filters  3   a  through  3   c  are positioned in a vicinity of the the crossed section  14   c.    
         [0075]    Differently from the filter  3  of the first through third embodiments, the filter  43  is constituted so as to protrude from the groove section  2  upward by 200 μm or more, and the protruded portion is a moving element section  43   d . A plate section  40  with electrodes is provided on a surface of the portion of the main body  8  provided with the waveguides  14   a  and  14   b . A side surface  40   x  of the plate section  40  with electrodes is provided with a plurality of electrodes  44  which function as stators for the moving element section  3   d , and a three-phase wiring section  45  which applies a three-phase driving voltage to the plural electrodes  44 . A plate section  41  is provided on a surface of the main body  8  provided only with the waveguide  14   a . It is noted that the plural electrodes  44  are covered with an insulating film  47  as mentioned later but are not shown in FIG. 19 in order to simplify the explanation.  
         [0076]    The insulating film  47  for covering the electrodes  44  and the three-phase wiring section  45  are provided on the side surface  40   x  of the plate section  40  with electrodes where the electrodes  44  and the three-phase wiring section  45  are provided. Moreover, the plate section  40  with electrodes is constituted by an insulating material. Similarly to the second embodiment, the electrodes  44  are made of metal films with thickness of 1000 Å and width of 5 μm, for example, and gaps between the electrodes are 5 μm.  
         [0077]    [0077]FIG. 20 is a sectional view of the optical switch  1   c . The electrodes  44  are opposed to the moving element section  43   d  on a side surface  43   x  of the filter  43  put into the groove section  2  via the matching oil  6  and the insulating film  47 . As shown in FIG.  21 , the filter  43  has interference filters  3   a  through  3   c , which are provided so as to be opposed to a side surface of the groove section  2 , and a notched section  43   e  for transmitting all incident lights.  
         [0078]    Further, in the present embodiment, as shown in FIG. 21, the moving element section  43   d  is provided on the top portions of the notched section  43   e  and the interference filters  3   a  through  3   c . Since the operation of the optical switch  1   b  having such a structure is similar to that of the first embodiment, the description thereof is omitted.  
         [0079]    In the second through fourth embodiments, differently from the first embodiment, the electrodes  24  through  44  which function as stators are provided onto a layer different from the waveguides  14   a  and  14   b . Therefore, the electrodes  24  through  44  in the optical switch in the second through fourth embodiments may be provided onto a position which is overlapped with the waveguides  14   a  and  14   b  or a position which is not overlapped with the waveguides  14   a ;and  14   b  viewed from the upper surface of the optical switch.  
         [0080]    In addition, in the first through fourth embodiments, another switching member, such as a micromirror instead of the filter, as well as the moving element section may be provided in the groove section so as to be opposed to the electrodes. As a result, the switch member provided so as to cross the waveguides is moved by the inductive charge type electrostatic system, so that an optical switch which does not require a movable plate and a heat radiating mechanism can be realized.  
         [0081]    Further, in the first through fourth embodiments, instead of insulating matching oil to be sealed into the groove section, an insulating film may be provided onto the filter  3 .  
         [0082]    A relationship between the electrodes functioning as stators and the three-phase wiring section for applying a three-phase driving voltage to the electrodes may be as shown in FIG. 22 or  23 , for example. Namely, as shown in FIG. 22, wirings  52   a  through  52   c  which are electrically connected with electrodes  51   a  through  51   c  may be provided, and electrodes  53   a  through  53   i  may be provided with contact holes  54   a  through  54   i , respectively. A three-phase driving voltage is applied to the electrodes  51   a  through  51   c . The electrodes  53   a  through  53   i  function as stators. The contact holes  54   a  through  54   i  electrically connect the electrodes  53   a  through  53   i  to the wirings  52   a  through  52   c , respectively.  
         [0083]    The electrodes  53   a ,  53   d  and  53   g  are connected with the wiring  52   a , which is provided via the insulating film, through the contact holes  54   a ,  54   d  and  54   g . The electrodes  53   b ,  53   e  and  53   h  are connected with the wiring  52   b , which is provided via the insulating film, through the contact holes  54   b ,  54   e  and  54   h . The electrodes  53   c ,  53   f  and  53   i  are connected with the wiring  52   c , which is provided with the insulating film, through the contact holes  54   c ,  54   f  and  54   i.    
         [0084]    As shown in FIG. 23, a flexible substrate  60  having wirings  62   a  through  62   i  is provided so as to be electrically connected with electrodes  61   a  through  61   c  to which a three-phase driving voltage is applied. Electrodes  64   a  through  64   i  which function as stators are electrically connected with the wirings  62   a  through  62   i  of the flexible substrate  60  via ACF (anisotropy conductive film)  63 . Therefore, the electrodes  64   a ,  64   d  and  64   g  are connected with the electrode  61   a  through the wirings  62   a ,  62   d  and  62   g , the the electrodes  64   b ,  64   e  and  64   h  are connected with the electrode  61   b  through the wirings  62   b ,  62   e  and  62   h , and the electrodes  64   c ,  64   f  and  64   i  are connected with the electrode  61   c  through the wirings  62   c ,  62   f  and  62   i.    
         [0085]    With the above structure, the electrodes  64   a  through  64   i  having width of 5 μm provided with intervals of 5 μm can be electrically connected with the electrodes  61   a  through  61   c  having width of 100 μm provided on the flexible substrate  60  with intervals of 100 μm.  
         [0086]    Next, there will be explained below an embodiment of an optical switch line provided with a plurality of optical switches. FIG. 24 is a plan view when a plurality of optical switches are provided. In the present embodiment, an optical switch line  100  is constituted so that the optical switches  101   a  through  101   c  having one of the structures in the first through fourth embodiments are arranged linearly. In the optical switch line  100 , a waveguide  114   a  crosses waveguides  114   b  through  114   d , and groove sections  102   a  through  102   c  are provided on the crossed sections, respectively, and filters  103   a  through  103   c  are put into the groove sections  102   a  through  102   c , respectively.  
         [0087]    An optical fiber  104  is connected with an input side (left in the drawing) of the waveguide  114   a , and an optical fiber  105  is connected with an output side (right in the drawing) of the waveguide  114   a . Optical fibers of an optical fiber array  106  are connected with output sides (downward in the drawing) of the waveguides  114   b  through  114   d , respectively.  
         [0088]    When a wavelength multiplexed light flux where lights with a plurality of wavelengths are superposed enters from the optical fiber  104 , filters  103   a  through  103   c  provided in the groove sections  102   a  through  102   c , respectively, are moved by using the inductive charge type electrostatic system, so that the light flux can be output from different optical fibers per wavelength.  
         [0089]    Therefore, similarly to the above embodiment, when an optical switch line is composed of n-numbered optical switches, after a light where n-numbered wavelengths are multiplexed is divided into n-numbered optical fibers, they are directly input into 1×n-numbered optical switches without switching output, so that lights with arbitrary wavelengths can be output to the n-numbered optical fibers for output. Therefore, a conventional expensive branching filter or the like is not required, and a number of the optical switches can be reduced and loss of a light can be reduced.  
         [0090]    As mentioned above, according to the present invention, after a driving voltage is applied to the stators and the moving element is electrostatically induced, the driving voltage is switched so that an electrostatic force acts upon the moving element and the stators. Since the electrostatic force is utilized so as to move the switching member, the stators can be located accurately per pitch. Moreover, since electrodes are arranged as stators so that a driving mechanism of the switching member can be structured, the driving mechanism can be miniaturized. Further, since the switching member which is provided on an optical path of an optical waveguide guides a light to different directions according to wavelengths, an incident light where wavelengths are multiplexed can be output separately by switching it per wavelength. Therefore, an additional branching filter or the like is not required, so that an optical communication system using an optical switch can be simplified.  
         [0091]    In addition, since a plurality of electrodes to be stators are provided on different portion from optical waveguides, excessive loss of a waveguide light for propagating on an optical waveguide can be prevented. In addition, a plurality of electrodes are not constituted in a groove section but provided on a different layer, so that the stators to be electrostatic force generating section can be constituted simply.  
         [0092]    Further, when a plurality of optical switches are provided on one optical path, a wavelength multiplexed light is not branched into a plurality of optical fibers but is directly input into optical switches arranged in series, so that lights with arbitrary wavelengths can be output to the respective optical fibers for output. Therefore, a conventional expensive branching filter or the like is not required, and a number of optical switches is reduced, thereby reducing a loss of a light.  
         [0093]    Although the present invention has been fully described by way of examples with reference to the accompanying drawings, it is to be noted that various changes and modifications will be apparent to those skilled in the art. Therefore, unless otherwise such changes and modifications depart from the scope of the present invention, they should be construed as being included therein.