Silicon-based electro-absorption modulator and preparation method thereof

Abstract

The invention provides a silicon-based electro-absorption modulator and a preparation method thereof. The modulator uses voltage to adjust the light absorption coefficient of a semiconductor on the basis of an electro-absorption mode, and then the intensity of an optical signal is adjusted. Silicon is a weak electro-optical material, so that the silicon is introduced into material germanium whichhas a remarkable electro-optical absorption adjusting effect in a communication wave band C wave band and is compatible with the CMOS technology. Through an epitaxial growth modulation layer (200), light beams are smoothly coupled into and coupled out of the modulation layer (200), oscillation of light field power of the light beams between the modulation layer and a waveguide layer is not generated, the dependence relation between the insertion loss of a device and the length of the modulation layer is eliminated, meanwhile, different working wavelengths can be achieved by adjusting alloy components in the modulation layer (200), and the modulation efficiency is high.

Description

technical field [0001] The invention relates to the field of optical interconnection, in particular to a silicon germanium electric absorption modulator. Background technique [0002] With the continuous development of integrated circuits and the continuous improvement of integration density, traditional electrical interconnection has become the main bottleneck for performance improvement, mainly manifested in: delay increase, power consumption increase, and signal crosstalk increase. Due to the characteristics of high speed, high bandwidth and low power consumption of optical interconnection, on-chip optical interconnection based on silicon-based photonic devices is expected to solve the limitation of traditional electrical interconnection on the development of integrated circuits. Among them, the silicon-based electro-optic modulator is one of the key devices for silicon-based optical interconnection, and it is also an important research topic in recent years. There are t...

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Problems solved by technology

The structure proposed by the University of Ghent requires selective etching of silicon, chemical mechanical polishing is required after the epitaxy of silicon germanium, and an optical coupler (taper) structure is made, and the process is relatively complicated; the structure proposed by Huawei requires PN junctions to be fabricated On silicon, germanium is directly selected for epitaxy on silicon, and no subsequent etching or thinning process is required. However, since the PN junctions are all made on silicon, there is a potential barrier at the silicon-germanium interface, and the distributed electric field in germanium is very weak, requiring a large The bias voltage can only work, and because there is no taper structure, the insertion loss of the device is very sensitive to the length of the modulation layer, and the process tolerance is small; and the structure of the vertical PIN junction proposed by the Institute of Semiconductors, Chinese Academy of Sciences is also more complicated. Sub-growth, etching and doping processes, and in order to make n ++ Si is easy to manufacture, and the silicon germanium modulation layer is wider, resulting in a multi-mode modulation layer, which affects communication capacity and transmission distance

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