JP2661969B2 - Variable optical splitter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an optical variable branching device used in optical communication and the like.

[Conventional technology]

As shown in FIG. 5 (a), a conventional variable optical splitter has a circular plate whose reflectivity r is continuously changed from 0 to 1 in the circumferential direction.
11 is rotated around a shaft 13 by a motor 12 and fixed at a point having a desired reflectance as shown in FIG. 5 (b). When input light from a light source 14 is incident thereon, output light A Output the light quantity of input light × (1-r), and output light B outputs the light quantity of input light × r. By rotating the disk 11, a variable optical splitter having an arbitrary split ratio can be obtained.

[Problems to be solved by the invention]

However, the conventional variable optical splitter as described above has a drawback that a large power consumption is required because a motor or the like is required to rotate the disk. SUMMARY OF THE INVENTION An object of the present invention is to provide an optical variable splitter having no moving parts and low power consumption.

[Means for solving the problem]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has a structure in which light traveling in the T-shaped optical waveguide is provided on both sides of a junction of the T-shaped optical waveguide made of a material having an electro-optic effect. A multilayer electrode having conductive layers stacked at intervals of m / 2 (where m is a natural number) times the wavelength along the direction, the surface of the conductive layer forms an angle of 45 ° with the incident direction of the light, And a variable light splitter which is installed so as to form an angle of 90 ° with respect to both side surfaces of the connecting portion, wherein the amount of light reflected and transmitted is changed by changing the voltage applied to the multilayer electrode. It is characterized by doing so.

[Action]

When the voltage applied to the multilayer electrode is changed, the refractive index of the junction of the T-shaped optical waveguide changes, and therefore the amount of reflection and transmission of the input light to the junction changes.

〔Example〕

Lithium niobate (LiNb)
O ₃ ), a T-shaped optical waveguide 1 having an intersecting portion 2 as shown in FIG. 2 is produced. The input light is incident from a point a, passes through the intersecting portion 2, and is normally emitted to a point b. On the other hand, Fig. 3 shows a thickness of 0.
In a perspective view of the multilayer electrode 3 in which four 230 μm conductive layers 6 and five 0.230 μm thick insulating layers 7 are alternately stacked in parallel, the surface of the conductive layer 6 is defined as a reference plane 6a, and the interval between the conductive layers 6 is It is half the wavelength λ along the light traveling direction. Reference plane of conductive layer 6
a forms an angle of 45 ° with respect to the direction of incidence of light and forms an angle of 90 ° with the side surface 8. The conductive layer 6 was made of aluminum, and the insulating layer 7 was made of silicon dioxide. The multilayer electrode 3 configured as described above is connected to the junction 2 of the T-shaped waveguide 1 in FIG.
The optical variable branch device 5 as shown in FIG. When a voltage is applied between the two multilayer electrodes 3 and 3 via the lead plate 4 in the state of FIG. 1, as shown in FIG.
Portion of the Intersection 2 of the V-Shaped Optical Waveguide 1 Where a Voltage is Applied
The refractive index of 2a changes, and the input light is partially reflected by this portion 2a, output at a point C at a 90 ° angle change, and the rest goes straight on and is output at a point b. Reference surface 6a of conductive layer 6 of multilayer electrode
Is set to 1/2 of the wavelength λ to adjust the phase of the output light at the point C.

〔The invention's effect〕

As described above, the variable optical branching device of the present invention has a multi-layered electrode provided on both sides of the junction of the T-shaped optical waveguide, and changes the voltage applied to the multi-layered electrode to change the T-shaped optical waveguide. Since it has a structure in which the refractive index of the contact portion is changed, it is possible to configure a variable optical splitter having no movable portion, so that power consumption can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view of a variable optical splitter of the present invention, FIG. 2 is a perspective view of a T-shaped optical waveguide, FIG. 3 is a perspective view of a multilayer electrode, and FIG.
FIG. 5 is a cross-sectional view showing a portion where the refractive index of an intersecting portion of a T-shaped optical waveguide changes, and FIG. 5 is a schematic view of a conventional variable optical splitter. 1 ... T-shaped optical waveguide, 2 ... Intersection part, 2a ... part, 3
... multilayer electrode, 4 ... lead plate, 5 ... variable optical branching device,
6 ... conductive layer, 7 ... insulating layer, 8 ... side surface.

Claims (1)

(57) [Claims] 1. An optical system according to claim 1, wherein both sides of the junction of the T-shaped optical waveguide made of a material having an electro-optical effect are provided with a wavelength of m / 2 (where m Is a natural number) a multilayer electrode having conductive layers stacked at an interval of times
An optical variable splitter, wherein a surface of the conductive layer forms an angle of 45 ° with respect to the incident direction of the light, and is formed so as to form an angle of 90 ° with respect to both side surfaces of the connecting section, A variable optical splitter characterized in that the amount of light reflected and transmitted is changed by changing the voltage applied to a multilayer electrode.