Optical modulator

Abstract

The optic modulator comprises a substrate 1 formed of a material having electro-optical effect, an optical waveguide formed on the substrate, and an electrode 3 for modulating the light passing through the optical waveguide. The optical modulator is characterized in that an electric signal connection pad unit 6 is provided on a part of the electrode, and in that the thickness of the substrate which is located at least on a lower part of the electric signal connection pad unit 6 and directly or indirectly continuous to the electric signal connection pad unit 6 is thinner than the thickness of other parts of the substrate. Present invention offers an optical modulator capable of efficiently transmitting electric signals to an acting portion of a signal electrode with acting on an optical waveguide even when the electric signals are in high frequency zone, and capable of performing high frequency broad band operation.

Description

technical field [0001] The invention relates to an optical modulator, in particular to an optical intensity modulator or a phase modulator or a polarization applicable to high-speed and large-capacity optical fiber communication. modulators for light modulators. Background technique [0002] In recent years, with the advancement of high-speed and large-capacity optical fiber communication systems, high-speed modulators using materials with electro-optical effects such as lithium niobate for the substrate, represented by external modulators, have been put into practical use. Such high-speed modulators such as figure 1 As shown, on a substrate 1 having an electro-optical effect, an optical waveguide 2 for guiding light waves, a signal electrode 3 for applying a high-speed modulation signal in the microwave band to the light waves, and a modulation electrode 4 composed of a ground electrode 4 are formed. electrode. [0003] Light waves enter the optical waveguide 2 from the ...

AI Technical Summary

Problems solved by technology

Therefore, the electrical signal transmitted to the action portion 8 of the signal electrode 3 is attenuated, making it difficult to effectively modulate the light wave conveyed in the optical waveguide.

[0006] For this purpose, microwaves are reduced by making the shape of the signal electrode 3 and the ground electrode 4 into a coplanar planar electrode structure that integrates the coaxial cable and impedance, or by making the corners of the signal electrode 3 gentle. Attempts to reduce losses such as reflection or leakage, but in the high-frequency region above 20GHz, it is difficult to achieve effective reduction

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