Optical antenna, phased array laser radar and two-dimensional scanning method of optical antenna

Abstract

The invention provides an optical antenna, a phased array laser radar and a two-dimensional scanning method of the optical antenna. The optical antenna comprises an SOI substrate, a waveguide structure layer, a spacer layer, an annular grating structure layer and a protection layer; a waveguide structure layer is formed on the top silicon layer of the SOI substrate; the spacer layer, the annular grating structure layer and the protection layer are sequentially arranged on the waveguide structure layer; the waveguide structure layer comprises a radiation type strip-shaped waveguide array, speckle conversion structures and a circular flat plate coupling region, wherein the radiation type strip-shaped waveguide array is connected with the circular flat plate coupling region through the speckle conversion structures; the difference value of the refractive index of the annular grating structure layer and the refractive index of the spacer layer and the difference value of the refractive index of the annular grating structure layer and the refractive index of the protection layer are both greater than a preset threshold; and the refractive index of the annular grating structure layer ishigher than the refractive indexes of the spacer layer and the protection layer. Light waves can be successfully emitted upwards and inhibited from being emitted downwards, so that high radiation efficiency is obtained; the radiation type strip-shaped waveguide array can be divided into multiple groups; and the light of the strip-shaped waveguide groups in different directions work in a time-division manner, so that two-dimensional scanning can be realized.

Description

technical field [0001] Embodiments of the present invention relate to the field of radar technology, and in particular to an optical antenna, a phased array laser radar, and a two-dimensional scanning method for the optical antenna. Background technique [0002] The concept of phased array lidar has long been proposed, and various design schemes are constantly being developed. Its basic modules are also mature, such as light source module, beam splitting module, phase modulation module, etc. However, in the optical antenna module, how to efficiently export the phase-modulated light of each waveguide to the photonic integrated circuit is still a huge challenge. This is because the refractive index of the waveguide is much larger than that of air, and it is very difficult to couple light from the waveguide into free space, so that the radiation efficiency of the optical antenna is extremely low, which seriously affects its utilization. [0003] At present, the international o...

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Problems solved by technology

[0005] The embodiment of the present invention provides an optical antenna, a phased array laser radar and a two-dimensional scanning method of the optical antenna, which solves the problem that the conventional grating is used in the grating optical antenna in the prior art, resulting in the coupling from the grating to the outside of each waveguide. The light divergence is serious, and the upward radiation efficiency is extremely low, which leads to the technical problem of extremely low energy utilization rate of the optical antenna. It also solves the problem that the existing array grating optical antenna can only realize one-dimensional scanning for the single-wavelength input. Another dimension of scanning is realized by adjusting the wavelength, which seriously affects the technical problems of the practical application of phased array lidar

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