JP2725349B2 - Optical switch - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical transmission component, and more particularly to an optical path switching element.

[Prior Art] As a device for switching an optical path, as shown in FIG. 4, a pair of optical fiber arrays 1A and 1B formed by fixing two optical fibers F1 and F2 in a parallel arrangement are arranged facing each other. The optical paths A, D, and C are moved by moving the fiber array 1B of
A structure that switches from a state in which the optical paths A and B are connected to a state in which the optical paths A and B are connected is used.

[Problems to be Solved by the Invention] However, in the above-described conventional structure, it is difficult to accurately match the fiber arrangement pitch between the incident side fiber array and the exit side fiber array. In particular, although not shown, in the case of an optical switch using fiber arrays in which a large number of fibers are arranged, the loss characteristic in which the pitch error is accumulated deteriorates.

In the conventional one, the fiber array on the input side and the fiber array on the output side are individually manufactured and set at desired fixing points. However, it is difficult to make the outer shape accuracy of these fiber arrays on the order of μm. It was difficult to align the optical axis well.

Furthermore, in order to drive the connected fiber,
There were also problems with long-term reliability and drive speed at the fiber junction.

[Means for Solving the Problems] First, a planar waveguide circuit is formed on a substrate serving as a mother body by an ion exchange method. This matrix waveguide circuit is formed by forming three parts, a waveguide section for attaching the fiber on the incident side, an intermediate waveguide section for switching, and a waveguide section for attaching the fiber on the exit side. Then, the above-mentioned mother circuit board is cut and separated into each waveguide unit, and the waveguide substrates for mounting the input / output fibers on both sides are fixed, and the intermediate switching waveguide substrate is moved in the transverse direction using appropriate driving means. By doing so, the optical path is switched.

[Operation] Since the waveguide for incidence, the waveguide for switching in the middle, and the waveguide for emission are all obtained by dividing the waveguide circuit formed on the common base substrate, the opposing substrate end face, that is, the base The arrangement pitch of the waveguides on the cut surface of the substrate is completely the same. The same can be said for the distance from the side edge of the substrate to the waveguide.

Therefore, the optical axes of the waveguides can be aligned with high precision by a very simple operation of bringing the respective waveguide substrate into contact with a certain reference plane.

EXAMPLES Hereinafter, the present invention will be described in detail based on examples shown in the drawings.

FIG. 1 shows an example of a bypass switch, in which three waveguide substrates 11, 12, 13 are arranged in series on a fixed base 10, and input / output optical fibers 14A are provided on the substrates 11, 13 located on both sides, respectively. ,14
B, 14C, and 14D are connected to each other, and both substrates 11, 13 are fixed to the fixed base 10, and the substrate 12 located in the middle is shown from the position shown in FIG. 1A to the position shown in FIG. The optical path is switched by sliding using an external driving device.

More specifically, first, a pair of linear waveguides 15A, 15B running in parallel at an interval P is formed on a quadrangular base substrate 20 having a size obtained by combining the above-described waveguide substrates 11, 12, 13. Further, a curved waveguide 15C independent of these is formed on the outside thereof.

This curved waveguide 15C has both ends terminated in the substrate,
In the vicinity of both ends, the pattern is parallel to the linear waveguides 15A and 15B, and at one end, the interval between the adjacent linear waveguides 15B is P, and the interval between the other end and the linear waveguide 15B is 2 × P.

The waveguides 15A, 15B, and 15C as described above are formed, for example, by forming a mask film having an opening of a predetermined pattern on a glass substrate by using a well-known photolithography technique, and increasing the refractive index of the substrate glass through the opening. Can be formed in a precise pattern by diffusing and invading by exchange with ions in the glass.

In addition, V-grooves for fixing the tips of the input / output optical fibers 14A to 14D are formed in the substrate portions at both ends of both the linear waveguides 15A and 15B.

The base substrate 20 on which the waveguides are formed as described above is cut perpendicular to the optical axis of the waveguide at two places where the waveguides 15A, 15B, and 15C are separated, and the individual waveguide substrates 11, 12, 13
Get.

By arranging the substrates 11, 12, 13 obtained in this way in contact with the reference surface 10A provided on the fixing base 10, all the linear waveguides in the three divided substrates 11, 12, 13 are all The optical axes are aligned. In this state, the input / output waveguide substrate
11 and 13 are fixed to the fixed base 10. The intermediate waveguide substrate 12 is connected to a driving device (not shown).

Using the switch having the above configuration, for example, the trunk fibers 14A and 14B forming an optical local loop are connected to the waveguide ports A and B, respectively, and the input / output end fibers 14 of the terminal are connected.
Connect D and 14C to waveguide ports D and C.

In the waveguide positional relationship as shown in FIG. 1 (a), an optical signal passing through the trunk enters from port A, passes through a straight waveguide passing through each of the substrates 11, 12, and 13 and then enters a terminal from port D. The signal light processed in step (a) enters from port C, passes through a straight waveguide, and enters from port B into trunk fiber 14B.

In addition, as shown in FIG.
When moved by the distance of P, the left end of the curved waveguide 15C is connected to the adjacent straight waveguide 15B, and the right end of the curved waveguide 15C is connected to the outer straight waveguide 15A.

In this state, the optical signal passing through the main line is the optical fiber 14A,
The terminal passes through the path of the curved waveguide 15C and the optical fiber 14B and bypasses the terminal. That is, when a trouble occurs in the terminal, the optical signal can be sent without interruption by switching to the position shown in FIG. 2 and 3 show another embodiment of the present invention. Figure 2 is one to four
FIG. 3 shows an example in which a two-to-two switch is configured. Each of these embodiments is the same as the first illustrated example except that the number of waveguides is different.

[Effects of the Invention] According to the present invention, the precision from the reference plane to the optical waveguide (fiber), which is difficult with the conventional method of outer shape processing, can be realized with high accuracy, and theoretically there is no displacement. Therefore, the optical axis can be adjusted only by setting the optical axis on the fixed base having the reference surface, and there is no need to perform a special alignment operation.

Further, since the material of each divided substrate provided with the input / output waveguide and the optical path switching waveguide is the same, there is no problem with respect to temperature change. That is, since each substrate moves by the same amount in the same direction from the reference fixed base in the same direction according to the expansion coefficient α of the substrate material, the optical axis of the waveguide does not shift.

[Brief description of the drawings]

FIG. 1 is a plan view showing a first embodiment of the present invention, FIG. 2 is a plan view showing a second embodiment of the present invention, and FIG.
FIG. 4 is a plan view showing an embodiment, in which (a) and (b) show switching states of optical paths, respectively, and FIG. 4 is a sectional view showing a conventional switch. 10 fixed base, 10A reference plane, 11, 13 input / output waveguide substrate, 12 optical path switching waveguide substrate, 14A, 14B, 14C,
14D …… Optical fiber, 15A, 15B, 15C …… Optical waveguide, 20 ……
Mother board.

Claims (1)

(57) [Claims] 1. An optical switch in which a drivable optical switching waveguide is disposed between a light input waveguide and an output waveguide, wherein each of the waveguides is a single base. An optical switch, wherein a waveguide formed on a substrate by an ion exchange method is a divided waveguide.