JPH04282608A - Optical waveguide device - Google Patents

Abstract

PURPOSE:To obtain the optical waveguide device which is small in size, allows easy handling and has a high extinction ratio by sticking micropolarizers to the end face of the input optical waveguide of the optical waveguide device or the end faces of the input and output optical waveguides thereof. CONSTITUTION:The waveguide 5 diffused with Ti is formed to a prescribed shape on an LiNbO3 substrate 7 and the micropolarizers 6, more specifically laminar poles, are stuck to the input end face 8 and output end face 8' thereof. The optical fibers 9 are mounted through these poles. As these laminar poles are extremely small as 30mum thickness and 1X1mm longitudinally and transversely and, therefore, the optical waveguide device can be constituted in a small size. The extinction ratio of the laminar poles is as high as about 50dB and has the performance exceptionally higher than the performance of the commercially marketed polarization plane maintaining fibers. The degradation in the extinction ratio is thus prevented.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical waveguide device that utilizes one polarization of light, and more particularly to an optical waveguide device that requires a high extinction ratio.

0002

[Prior Art] Generally, in optical waveguide devices such as optical switches and optical modulators, an electric field is applied to an optical waveguide provided on a substrate having an electro-optic effect to change the refractive index. Performs signal switching and phase modulation. Since the change in refractive index is anisotropic, light is modulated differently depending on polarization. If the light traveling through the waveguide has two types of polarization, each of them will be modulated differently, thereby reducing the extinction ratio.

FIG. 1 is an optical configuration diagram of a conventional optical waveguide device. In order to use only the necessary polarized light, a polarizer and polarization maintaining fiber are installed outside the optical waveguide device.
is provided. The size of such a polarizer is much larger than that of a typical optical waveguide device. Furthermore, the extinction ratio of commercially available polarization maintaining fibers is generally less than 30 dB, and furthermore, the direction in which polarization is maintained must be precisely aligned at the end face of the waveguide. In addition, the optical waveguide provided in the optical waveguide device generally has a depolarization effect.

[0004] Therefore, in the conventional optical waveguide device configuration, the polarizer is large, so the optical waveguide device structure cannot be made compact, and furthermore, there is a limit to the extinction ratio of the polarization-maintaining fiber. It is not possible to improve the extinction ratio of the entire optical waveguide device, it is difficult to handle by aligning the polarization maintaining direction of the polarization maintaining fiber with the optical waveguide device, and the optical waveguide on the optical waveguide device is difficult to handle. There are drawbacks such as a decrease in extinction ratio due to the polarization effect.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and involves attaching a minute polarizer to the input optical waveguide end face or the input/output optical waveguide end face of an optical waveguide device. An object of the present invention is to provide an optical waveguide device that solves the above problems.

[0006]

[Means for Solving the Problems] The present invention has been made in order to solve the above-mentioned technical problems, and provides an input guide for an optical waveguide device in which an optical waveguide is formed on an electro-optic crystal substrate. An optical waveguide device is provided, characterized in that a micropolarizer is attached to a waveguide end face or both end faces of an input/output waveguide.

For example, a Ti diffusion waveguide can be used as the waveguide used in the optical waveguide device of the present invention. Then, a minute polarizer, ie, a polarizing plate, is attached to the end face of the crystal plate of the input waveguide or input/output waveguide. As a polarizing plate that can be used for this purpose, for example, Lamipole can be used.

[0008]

[Function] In the micropolarizer according to the optical waveguide device configuration of the present invention, for example, Lamipole has a thickness of 30 μm and a length and width of 1 mm, which is very small, so the optical waveguide device configuration can be made small. . The extinction ratio of Lamipole is about 50 dB, which is higher than that of commercially available polarization-maintaining fibers.
The optical waveguide device of the present invention can prevent the extinction ratio from decreasing.

Furthermore, light can be directly input from the light source to the end face using a normal optical fiber, making it easy to handle. That is, since no polarization maintaining fiber is used, there is no need for axis alignment.

[0010] Furthermore, by attaching a minute polarizer to the output end face of the waveguide, it is possible to cut the extra polarization component caused by the depolarization effect of the optical waveguide on the optical waveguide device, and the extinction ratio can be reduced. deterioration can be prevented.

[0011] Next, the optical waveguide device of the present invention will be specifically explained by examples using the drawings, but the present invention is not limited thereto.

0012

Embodiment 1 FIG. 2 is a structural diagram showing an example in which the optical waveguide device of the present invention is applied to a Mach-Zehnder modulator. That is, a waveguide 5 in which Ti is diffused is formed in a predetermined shape on a LiNbO3 substrate 7, and a micropolarizer 6, specifically, a Lamipole is attached to its input end face 8 and output end face 8'. , through which an optical fiber 9 is attached.

[0013] In this way, an optical waveguide can be formed with a simple structure.

[0014]

Embodiment 2 FIG. 3 is a structural diagram showing an example in which the optical waveguide device of the present invention is applied to a phase modulator. LiNbO3
A micro polarizer 6 (lamipole) is attached to the input end face 8 and output end face 8' of the Ti-diffused waveguide 5 formed in the substrate 7, and an optical fiber 9 is coupled through them. be.

[0015]

Embodiment 3 FIG. 4 is a structural diagram showing an example in which the optical waveguide device of the present invention is applied to a directional coupler. LiNbO
3 A micropolarizer 6 (Lamipo
This is a structure in which optical fibers 9 are connected through the optical fibers.

[0016]

[Effects of the Invention] As explained above, the optical waveguide device of the present invention provides the above-mentioned effects. Putting these together, we get the following remarkable technical effects. That is, an optical waveguide device that is small, easy to handle, and has a high extinction ratio has been provided.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing the configuration of a conventional optical waveguide device.

FIG. 2 is a configuration diagram showing an example of a Mach-Zehnder modulator.

FIG. 3 is a configuration diagram showing an embodiment of a phase modulator of the present invention.

FIG. 4 is a configuration diagram showing an embodiment of a directional coupler of the present invention.

[Explanation of symbols]

Claims (1)

[Claims] 1. An optical waveguide device in which an optical waveguide is formed on an electro-optic crystal substrate, characterized in that a micropolarizer is attached to an end face of the input waveguide or both end faces of the input/output waveguide. device.