Method for preparing multi-layer ridge optical waveguide

Abstract

The invention discloses a method for preparing a multi-layer ridge optical waveguide. The method has an etching sequence from deep etching to shallow etching, wherein the deep etching comprises the following steps of: forming a groove and a silicon mesa on a top silicon layer of a silicon chip, filling the groove and flattening the silicon chip; and the shallow etching comprises the following step of removing one part of the silicon mesa, wherein a groove with a narrow opening is more easily filled and closed. The alignment offset in a multi-etching step is reduced by a cross photoetching method; moreover, an oxidation and deoxidation method is adopted to solve the problem of a rough surface of the waveguide, and the initial width of a silicon ridge on the waveguide is reduced simultaneously.

Description

technical field [0001] The invention relates to a preparation method of a multilayer ridge optical waveguide. Background technique [0002] Optical waveguides are used in planar waveguide circuits (PLC) in the prior art. For example, silicon-based waveguides can be fabricated on SOI. Patents US 5078516, US 7016587, US 7499620, US 7539373, US2009 / 0252456 and US 2010 / 0055906 disclose some examples of waveguide devices and their fabrication methods, which are hereby incorporated by reference. [0003] The existing manufacturing process of the silicon ridge planar optical waveguide includes multiple photolithography steps and corresponding silicon etching steps. In these processes, the sequence of multi-step etching is generally performed sequentially, first on the upper or top layers, and then on the lower layers. Therefore, in the existing process, shallow etching is generally carried out first, and then deep etching is carried out. The shallow etching causes the surface of...

AI Technical Summary

Problems solved by technology

In addition to the difficulties of lithography on non-planar surfaces, alignment errors or shifts during multiple etching steps can severely affect the optical performance of silicon-ridge planar lightguides

At the same time, the etching process will make the silicon wafer have a rough surface with various surface states, which will increase the optical scattering loss

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