Semiconductor Light-Receiving Element Tapered Optical Input
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Solution Overview
Problem
Existing semiconductor light-receiving elements face challenges in achieving high efficiency and reducing reflection when integrated with micro-ring LDs on a single chip, as they struggle with unstable output due to significant return light reflection.
Innovation Solution
A semiconductor light-receiving element is designed with a silicon-thin-line waveguide and a tapered optical input part, where the waveguide is spirally connected and tapered near the light-receiving part, reducing reflection by optimizing the waveguide's width and position relative to the optical input part, and using a semiconductor multilayer structure for efficient light detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional light-receiving element is used with micro-ring LD, then the system can be integrated on one chip, but the return light reflection is significant causing unstable output
Solution Approach 1:
An optical input part is introduced as an intermediary component between the waveguide and the light-receiving core. This optical input part with its tapered structure acts as a mediator that gradually transitions the light from the waveguide into the light-receiving region, reducing abrupt reflections and enabling stable operation while maintaining on-chip integration capability.
2Device complexity
If the waveguide is directly connected to the light-receiving part, then the structure is simple, but the return light reflection is high
Solution Approach 1:
The connection between the waveguide and light-receiving part is segmented into two distinct sections: a waveguide portion and an optical input part with tapered geometry. This segmentation allows the optical input part to specifically address the reflection problem through its gradual tapering structure, while the waveguide maintains its simple rectangular cross-section design.
3Object-generated harmful factors
If the optical input part is positioned far from the waveguide, then reflection is reduced, but coupling efficiency decreases
Solution Approach 1:
The optical input part employs a tapered geometry that gradually changes the width from the waveguide side toward the light-receiving core. This curved/transitional shape allows light to be gradually coupled from the waveguide into the light-receiving region, maintaining high coupling efficiency while the tapered profile simultaneously reduces abrupt reflections compared to a direct rectangular connection.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration significantly reduces return light intensity to -48 dB or less, achieving a quantum efficiency of 90% or more, enabling stable operation and high-efficiency optical transmission/reception suitable for compact, integrated micro-ring LD systems.
Implementation Method 1
a silicon-thin-line waveguide configured to couple light with the optical input part
Implementation Method 2
a light-receiving part provided on a substrate and having a semiconductor multilayer structure
Data Source
AI summary
According to one embodiment, a semiconductor light-receiving element, includes a light-receiving part provided on a substrate and having a semiconductor multilayer structure of a circular outer shape, a optical input part formed of a peripheral portion of the semiconductor multilayer structure, and having a tapered front end, and a silicon-thin-line waveguide configured to couple light with the optical input part. The waveguide includes a linear part extending through the optical input part to an at least one area of an upper-side area and a lower-side area of the light-receiving part, and a spiral part connected to the linear part and formed in the at least one area.