Front-end input waveguide structure of a directionally coupled optical waveguide detector

Abstract

The invention belongs to the field of optoelectronic technology, and discloses a front-end input waveguide structure of a directionally coupled optical waveguide detector, including a substrate layer, a cover layer, a lower waveguide layer, a gap layer, an upper waveguide layer, and an absorption layer stacked in sequence from bottom to top , the substrate layer, the cover layer, the lower waveguide layer, the gap layer, and the front end of the upper waveguide layer are flush, the absorbing layer is located on the rear upper surface of the upper waveguide layer, the gap layer is the coupling layer, and the front end of the absorbing layer and the front end of the upper waveguide layer The distance is twice the coupling length. The invention overcomes the shortcomings of the waveguide detector and the horizontal coupling waveguide detector, can effectively increase the photocurrent, and also solves the problem of overheating and burning of the front end of the waveguide due to the mode evolution problem.

Description

technical field [0001] The invention belongs to the field of optoelectronic technology, and relates to a waveguide photodiode, in particular to a front-end input waveguide structure of a directional coupling optical waveguide detector. Background technique [0002] The high-power high-speed photodetector is a detection device based on the interaction between light and matter, and its function is to convert the incident light signal into a high-power high-frequency signal. High-power high-speed optical detector is an indispensable device in optically controlled phased array radar, ultra-high-speed test system and optical fiber LAN communication, and its performance plays a decisive role in the whole system. [0003] Conventional vertical-incidence photodetectors cannot meet both high-speed and high-power requirements. The main reasons are as follows: one is the saturation effect, which limits the photocurrent; the other is the long transit time, which limits the response fre...

AI Technical Summary

Problems solved by technology

[0007] The existing problems of waveguide detectors are: the distribution of photocurrent along the waveguide is uneven, it is exponentially attenuated, and the coupling loss is large; the photocurrent is very strong at the front end of the waveguide, and gradually weakens in the direction of propagation, and the front end of the waveguide determines the photocurrent. saturation value, which limits the incident optical power

[0008] In 2008, in order to solve the problem of uneven photocurrent distribution and large coupling loss of waveguide detectors, the University of California, San Diego proposed a directional coupling photodiode solution

This structural defect is: the air gap at the upper end of the coupling layer 4 has a great influence on the coupling length and absorption length, and when the width of the air gap changes, it will lead to uneven photocurrent distribution

The excited fundamental supermode and the first-order supermode are necessary for the detector to work, but the high-order supermode will cause the front end of the waveguide to be burned. local overheating

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