JPH05257069A - Optical switch - Google Patents

Abstract

PURPOSE:To obtain the self-holding type optical switch which is used to switch an optical signal. CONSTITUTION:The optical switch is equipped with an optical waveguide substrate 12 which has an optical waveguide 11, a groove part 13 which is formed in a direction crossing the optical waveguide 11 at right angles, a glass piece 15 which is freely slidable in the groove part 13 and provided with a metallic mirror 14 crossing the optical waveguide 11 at right angles, a liquid metal holding groove 17 which is formed opposite across the optical waveguide 11 and holds liquid metal (mercury) 16 inside, electrodes 18A and 18B, and 19A and 19B which supply currents to the liquid metal 16 in the liquid metal holding groove 17, and a magnetic field application part which applies a magnetic field at right angles to the flowing direction of the currents. The currents are supplied to the liquid metal 16 to apply the magnetic field at right angles to the flowing direction of the currents, a Lorentz's force is made to operate on the liquid metal 16, which is moved in the liquid holding groove to cut off the optical waveguide 11 by the metallic mirror 14 provided at part of the glass piece; and input light which has passed through the optical waveguide is reflected to provide the operation of the self-holding type optical switch.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-holding type optical switch used for switching optical signals.

[0002]

2. Description of the Related Art Conventionally, a refractive index matching agent (for example, silicon oil) is injected into and removed from a groove traversing an optical waveguide to switch the transmission and reflection states, respectively. A waveguide type optical switch having a self-holding function has been proposed.

In such an optical switch, since the injection and removal of the refractive index matching agent are carried out by using a syringe mounted in a precise moving structure, even if the optical switch is highly integrated by an optical waveguide, a mechanical mechanism is not provided. Therefore, it is difficult to make it small. Further, since it includes a precise moving mechanism, it is difficult to improve the reliability as an optical switch.

In view of the above-mentioned circumstances, the present invention is different from the above-mentioned conventional optical switch in that it does not require a mechanical structure for moving the refractive index matching agent and is self-holding type which can be easily miniaturized. An object is to provide an optical switch.

[0005]

The structure of an optical switch according to the present invention for achieving the above-mentioned object is formed by an optical waveguide substrate having an optical waveguide formed therein and a substrate crossing in a direction orthogonal to the optical waveguide. A groove portion, a glass piece that is slidable in the groove portion and has a metal mirror provided on one side surface orthogonal to the optical waveguide, and an optical waveguide formed on the optical waveguide substrate are used as boundaries to communicate with both ends of the groove portion. A liquid metal holding groove formed opposite to each other and holding a liquid metal movably therein,
The liquid metal holding groove is provided with an electrode for applying an electric current to the liquid metal, and a magnetic field applying unit for applying a magnetic field in a direction orthogonal to the direction of the electric current. The glass piece provided with the metal mirror slides along the groove provided across the optical waveguide due to the force generated on the optical waveguide, and the optical waveguide is switched between the state of being blocked by the metal mirror and the state of not being blocked. It is characterized by

[0006]

In the optical switch having the above-mentioned structure, the glass piece partially attached with the metal mirror is inserted into the groove provided across the optical waveguide, and the glass piece leans to one of the two. At this time, the metal mirror does not block the optical waveguide, and conversely, when the metal mirror approaches the other side, the metal mirror blocks the optical waveguide. In order to move the glass piece, a current is passed through the liquid metal held in the liquid metal holding groove, and a magnetic field is applied in a direction orthogonal to the direction in which the current flows, and a Lorentz force is applied to the liquid metal. By working, the liquid metal in the liquid holding groove is moved. As a result, the glass piece slides in the groove along with the movement of the liquid metal, the metal mirror provided on a part of the glass piece blocks the optical waveguide, and the input light passing through the optical waveguide is reflected here. It will return and act as a self-holding optical switch.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the optical switch according to the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of an optical switch according to this embodiment. As shown in the figure, the optical switch according to the present embodiment includes an optical waveguide substrate (silicon) 10
An optical waveguide substrate (clad) 12 laminated on the upper surface of the optical waveguide 11 and having an optical waveguide 11 formed therein, a groove portion 13 formed across the optical waveguide 11 in a direction orthogonal to the optical waveguide 11, and slidable in the groove portion 13. And a glass piece 15 provided with a metal mirror 14 on one side surface orthogonal to the optical waveguide 11 by a process such as vapor deposition, and the optical waveguide 11 formed on the optical waveguide substrate.
Is formed as a boundary and is formed so as to face each other so as to communicate with both ends of the groove portion 13, and a liquid metal (mercury in this embodiment) is formed inside.
Liquid metal holding groove 17 for holding 16 movably, electrodes 18A, B, 19A, B for passing currents respectively through liquid metal 16 in the liquid metal holding groove 17, and orthogonal to the flowing direction of the current. And a magnetic field applying unit (not shown) for applying a magnetic field in the direction.

Groove 1 provided on the optical waveguide substrate 12
3 and the liquid metal holding groove 17 are processed by etching or the like. The metal mirror 14 is attached to the glass piece 13 by a process such as vapor deposition. The glass piece 15 inserted into the upper groove portion 13 has a structure of sliding along the groove portion 13 and works if some force is applied, but when the force is not working, the position is held by friction. Further, the liquid metal 16 injected into the liquid metal holding groove 17 constitutes one lump due to surface tension, but as shown in FIG. 1, mercury is injected into the groove with a space.

That is, as shown in FIG.
The surface of the mercury 16 is the glass piece 1
A small amount of mercury is injected with respect to the volume of the groove 17 so as not to push 5 back to the left. In addition, as described in FIG. 2 showing a cross section taken along the line II-II of FIG.
The lid 20 provided with the electrodes 19A and 19B is the optical waveguide substrate 12
The mercury 16 is sealed in the liquid metal holding groove 17 on the upper surface of the liquid metal holding groove 17.

Although not shown in the figure, a magnetic field is applied in a direction perpendicular to the surface of the optical waveguide substrate 12. The application of this magnetic field is realized by installing a permanent magnet such as ferrite above or below the optical waveguide substrate. In addition, in order to facilitate the sliding of the glass piece 15 and prevent the reflection of light on the glass surface, it is also an effective means to fill the gap of the groove 13 with a refractive index matching agent.

Next, a method of moving the glass piece for inserting and removing the metal mirror will be described with reference to FIG. Figure 3
FIG. 2 is a view of the optical waveguide substrate of FIG. 1 viewed from above. In the figure, the direction of the applied magnetic field is from the back side of the paper to the front side. From the lower electrodes 18A, 19A in the figure to the upper electrodes 18B, 19A
When a current is passed toward B, the Lorentz force acts on the mercury 16 and the mercury moves to the right side of the figure (see FIG. 3A). When the right and left mercury 16 both act to move to the right, the glass piece 15 is pushed by the surface of the left mercury 16 and slides to the right. Since mercury has a large surface tension, it does not enter the narrow space due to the capillary phenomenon, and finally the state shown in FIG. Even if the electric current is stopped, the glass piece 15 and the mercury 16 retain their positions due to the frictional force.

Next, when the direction of the electric current is reversed, the mercury 16
Since the direction of the Lorentz force acting on the
5 is pushed by the mercury 16 on the right side to move to the left side, and finally the state shown in FIG. In this state, the optical waveguide is blocked by the metal mirror 14, and the light incident from the lower optical waveguide in the figure is reflected and returned. The self-holding type optical switch of the present invention operates based on the above principle.

The above-described optical switch shown in FIG. 1 switches between transmission and blocking of one optical waveguide. As shown in FIG. 4, the self-holding optical switch of the present invention intersects with each other. By providing the optical waveguides 11A to 11D at the intersections thereof, a basic unit of the matrix optical switch can be constructed.

In the state shown in FIG. 4, that is, in the transmitting state, the light incident from the optical waveguide 11A is transmitted to the waveguide 11B, and the light from the optical waveguide 11C is transmitted to the optical waveguide 11D. When the glass piece 15 moves to the left and the metal mirror 14 blocks the optical waveguide, the light incident from the optical waveguide 11A is reflected to the optical waveguide 11D, and the optical signal is switched. N
An xN matrix optical switch can be constructed by arranging the units of the optical switch shown in FIG. 4 on an NxN lattice and coupling them by an optical waveguide.

Unlike an optical switch using a refractive index difference, an optical switch using a metal mirror has neither wavelength dependence nor polarization dependence of a phase shift (Goose-Henschen shift) on a reflecting surface, and the shift amount thereof is also different. When a metal such as silver or gold is used, the thickness is 0.1 μm or less, which does not limit the waveguide design. Therefore, it is understood that the optical switch of the present invention is basically polarization independent and wavelength independent. Since the reflection on the metal surface is used, the optical signal is always attenuated because the reflection is not total reflection. However, in the case of metal such as gold and silver, the light wavelength used for communication is 1.3 μm, 1.5 μm. In the vicinity, it has a reflection efficiency of about 98% and is practically no problem. Further, in the optical switch utilizing the difference in refractive index, the angle formed by the intersecting optical waveguides is set to 8 in order to satisfy the total reflection condition.
Although it cannot be less than 5 degrees (when the refractive index of the waveguide is 1.5), it can be crossed at a lower angle by using the reflection by the metal mirror, and the light guide when the optical switch is in the transmitting state. Crosstalk between the waveguides can be reduced.

[0016]

As described above, the self-holding type optical switch of the present invention has a self-holding function and is suitable for downsizing, in which the movement of the metal mirror is performed by the electromagnetic force acting on the liquid metal. A self-holding type optical switch having Furthermore, the self-holding type optical switch of the present invention has an effect that it is easy to integrate and realize a matrix optical switch. Further, since the self-holding type optical switch of the present invention is a self-holding type, it does not require driving power except when switching, so that it can be applied to an optical fiber core wire switching terminal in an optical transmission system. The system can be provided with a function of selecting the optical fiber core wire that enables switching, and the work involved in switching can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of an embodiment of a self-holding type optical switch according to the present invention.

FIG. 2 is a view of the self-holding optical switch of FIG. 1 according to the present invention II-
FIG. 11 is a sectional view taken along line II.

FIG. 3 is a diagram illustrating a self-holding function of a self-holding type optical switch and a principle of movement of a metal mirror.

FIG. 4 is a diagram illustrating a configuration when a self-holding type optical switch is applied to a constituent unit of a matrix optical switch.

[Explanation of symbols]

 10 Optical Waveguide Substrate (Silicon) 11 Optical Waveguide 12 Optical Waveguide Substrate (Clad) 13 Groove 14 Metal Mirror 15 Glass Piece 16 Liquid Metal (Mercury) 17 Liquid Metal Retaining Groove 18A, B, 19A, B Electrode

Claims (1)

[Claims] 1. An optical waveguide substrate having an optical waveguide formed therein, a groove formed transversely to a direction orthogonal to the optical waveguide, and one side surface which is slidable in the groove and orthogonal to the optical waveguide. A liquid metal for holding a liquid metal movably inside the glass piece provided with a metal mirror and the optical waveguide formed on the optical waveguide substrate as opposed to each other so as to communicate with both ends of the groove. A holding groove, an electrode for passing an electric current through the liquid metal in the liquid metal holding groove, and a magnetic field applying unit for applying a magnetic field in a direction orthogonal to the direction in which the current flows, are provided. The force generated on the liquid metal causes the glass piece provided with the metal mirror to slide along the groove provided across the optical waveguide, and the state where the optical waveguide is blocked by the metal mirror and the state where it is not blocked. It is characterized by switching to Optical switch.