Slow wave matching structure film type electrooptical modulator

Abstract

The invention discloses a slow wave matching structure film type electrooptical modulator. The modulator comprises an optical waveguide structure composed of a Y branch input waveguide, a Y branch output waveguide and a photonic crystal line defect waveguide and a microwave coplanar waveguide structure composed of a gradual change type periodic capacitive load electrode. The photonic crystal linedefect waveguide limits a light field located in a forbidden band area by introducing line defects, target displacement is applied to a target row of photonic crystal lattices of the photonic crystalline defect waveguide so as to regulate and control the speed of a light wave group and / or obtain wide-spectrum slow light, and electro-optic interaction is enhanced so as to reduce half-wave voltage;and the gradient periodic capacitive load electrode is used for slowing down the microwave wave velocity to match the microwave wave velocity with the optical wave group velocity so as to obtain a large bandwidth, and a gradient structure from an inductive region to a capacitive region is used for reducing microwave reflection so as to further improve the high-frequency characteristic. The optical waveguide structure is made of a high-dielectric-constant insulator electro-optic material film. The gradient periodic capacitive load electrode structure is made of a high-conductivity metal material.

Description

technical field [0001] The invention relates to the technical field of low-half-wave voltage and ultra-high-speed Mach-Zehnder electro-optic modulators, in particular to a film-type electro-optic modulator with a slow-wave matching structure. Background technique [0002] Optical fiber communication is one of the main pillars of modern communication. With the explosive growth of data communication services, people have put forward higher and higher requirements for communication bandwidth. The single-wavelength bandwidth of the current optical fiber communication system is moving from 2.5Gb / s and 10Gb / s to higher bandwidth. Loading information to the laser is divided into internal modulation and external modulation. The chirp caused by the internal modulation is relatively large, and its transmission distance is limited due to the dispersion effect of the optical fiber, and the modulation bandwidth is not high. External modulation mainly includes electro-absorption amplitu...

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Problems solved by technology

The chirp caused by internal modulation is large, and its transmission distance is limited due to the dispersion of the fiber, and the modulation bandwidth is not high

External modulation mainly includes electro-absorption amplitude modulator and electro-optic phase modulator. The inherent loss of electro-absorption modulator is large, and the shielding effect of modulation electric field caused by photo-generated carriers is easy to cause saturation of the modulator, and only the amplitude change is difficult to apply to advanced Modulation format; materials used in electro-optic modulators mainly include lithium niobate, organic polymers and semiconductors, etc., none of them can simultaneously meet the requirements of modern communication with large bandwidth, low half-wave voltage, low insertion loss, miniaturization and integration; and thin film Lithium niobate material is prepared by ion slicing and bonding process and has great potential in electro-optic modulators

[0003] In related technologies, thin-film lithium niobate modulators generally use traveling-wave electrode structures, but there is a contradiction between the half-wave voltage and bandwidth of thin-film lithium niobate modulators in related technologies. To reduce the half-wave voltage of the device, it is necessary to increase the length of the device. It will increase the loss of high-frequency signals, thereby reducing the bandwidth of the device, which needs to be solved

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