Electrooptical modulator with electrodes and waveguide groups matched in refractive index and design method thereof

Abstract

The invention discloses an electrooptical modulator with electrodes and waveguide groups matched in refractive index and a design method of the electrooptical modulator, and relates to the technical field of optical communication devices. The electrooptical modulator comprises a plurality of periodically repeated electro-optical modulation units, the electrodes of the electro-optical modulation units and the waveguides are equal in equivalent length, and each electro-optical modulation unit comprises a radio frequency electrode and a waveguide. The length of each radio frequency electrode is one cycle length L of the electro-optical modulator, and the waveguide comprises a first part and a second part which are connected in sequence. The first part is an optical waveguide of the modulator,and the second part is a photonic crystal waveguide with a delay function. Meanwhile, the length of the photonic crystal waveguide needs to meet the following condition that X * Np + (L-X) * No = L *Ne. The electrooptical modulator with the electrodes and the waveguide groups matched in refractive index is simple in structure, can effectively achieve the refractive index matching of the electrodes and the waveguide groups, is easy to achieve and is lower in cost.

Description

technical field [0001] The invention relates to the technical field of optical communication devices, in particular to an electro-optic modulator with matching refractive index of electrodes and waveguide groups and a design method thereof. Background technique [0002] In the design of the electro-optic modulator of the traveling wave electrode type, a key element is to ensure that the electrical signal and the optical signal of the modulator propagate forward synchronously in the modulator. This requires that the group velocity of the two is the same, that is to say, the group refractive index of the two must be the same. [0003] In electro-optic modulators with certain structures, the group refractive index of the electrical signal in the traveling-wave electrode is generally relatively large, for example, the refractive index of the traveling-wave electrode in a silicon optical modulator can reach 6; while the group refractive index of the waveguide is generally relativ...

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Problems solved by technology

[0005] However, the optical delay ring waveguide 2 has several curved waveguide structures. In order to match the group velocity of the waveguide with the group velocity of the traveling wave electrode, the length of the optical delay ring waveguide 2 cannot be too small; however, due to the limited space of the waveguide layout restrictions, and its length can not be too long, it can be seen that the matching scheme is not only complex in layout, but also in actual use, is greatly restricted, and its scope of application is small

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