Low-drive-voltage lithium niobateelectrooptical modulator and manufacturing method thereof

Abstract

The invention discloses a low-drive-voltage lithium niobateelectrooptical modulator. A ridge waveguide structure is made on an X-cut Y-pass lithium niobate crystal, and the electrode structures of theelectrooptical modulator are made on two sides of the ridge waveguide structure, so that the electric field between the electrode structures of the electrooptical modulator can be distributed along the horizontal direction. Compared with existing lithium niobateelectrooptical modulator, the lithium niobateelectrooptical modulator disclosed by the invention has the advantages that the modulation efficiency of an optical field can be remarkably improved by an electric field, and the drive voltage of a device is reduced. In other schemes, a low-dielectric-constant material can be adopted as a substrate wafer of a lithium niobate film, and the ridge waveguide structure is made on the lithium niobate film, thus the working bandwidth of the lithium niobateelectrooptical modulator can be effectively increased, and the drive voltage of the lithium niobateelectrooptical modulator can be lowered. The invention also provides a manufacturing method of the low-drive-voltage lithium niobateelectrooptical modulator.

Description

technical field [0001] The invention relates to the technical fields of optical fiber communication, coherent optical communication and microwave photonics, in particular to a low driving voltage lithium niobate electro-optical modulator and a manufacturing method thereof. Background technique [0002] The electro-optic modulator is one of the core devices in the optical fiber communication system, and it plays a key role in converting electrical signals to optical signals. With the continuous development of communication technology, the technology of using ultra-low loss optical fiber as the information transmission medium has also been applied to the technical fields of coherent optical communication and microwave photonics. [0003] In optical fiber communication, especially in coherent optical communication systems, the optical modules used are developing in the direction of low power consumption, and the reduction of power consumption of optical modules will inevitably ...

AI Technical Summary

Problems solved by technology

[0005] (1) The lithium niobate electro-optic modulator adopts a coplanar electrode structure, and the modulation efficiency of the electric field loaded on the coplanar electrode structure to the optical field is not high, which increases the driving voltage of the modulator;

[0006] (2) In order to realize the improvement of operating frequency or bandwidth of lithium niobate electro-optic modulators, especially high-frequency electro-optic modulators, it is often necessary to prepare a layer of silicon dioxide film with a thickness of 0.2 μm to 2 μm on the surface of lithium niobate as a buffer layer to reduce the effective refractive index of the microwave / millimeter wave signal and increase the characteristic impedance, and the introduction of the buffer layer inevitably leads to a voltage division effect, which increases the driving voltage of the electro-optic modulator

However, the electro-optic modulator made of Z-cut lithium niobate crystal has obvious DC drift phenomenon, which has a great impact on the long-term performance stability of the device.

In addition, the dry etching technology of plasma etching or the wet etching technology of hydrofluoric acid etching are often used to manufacture ridge-shaped optical waveguides. Problems such as high transmission loss of ridge structure optical waveguide

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