Optical Waveguide Modulation via Back-Surface Light Absorption
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current optical communication systems lack a practical, monolithic integration of mechanisms to modulate light in the 1.55 µm band using short wavelength light, such as GaAs, and do not have a general-purpose platform for optical integrated circuits, particularly for single-crystal silicon waveguides on SOI substrates.
Innovation Solution
A method for manufacturing an optical waveguide apparatus involving the formation of a single-crystal silicon core on a quartz substrate with a plasma or ozone treatment for surface activation, followed by bonding and mechanical delamination to create an SOI substrate, and integrating a light emitting device on the back surface to modulate optical signals with a simple structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a monolithic integration of modulation mechanism with 1.55 µm waveguide is implemented, then the device complexity is reduced and ease of manufacture is improved, but the manufacturing precision and reliability are challenging due to the need to integrate different material systems (GaAs and silicon)
Solution Approach 1:
The apparatus is divided into two separate substrates: a first substrate (quartz or silicon dioxide) for the waveguide and a second substrate (GaAs) for the light emitting device. This segmentation allows each component to be optimized and manufactured independently on its own substrate, avoiding the complexity of monolithic integration while achieving functional integration through subsequent bonding.
Solution Approach 2:
A bonding interface is introduced as an intermediary between the first substrate (waveguide) and second substrate (light emitting device). This bonding interface enables the coupling of different material systems (quartz/silicon dioxide and GaAs) that would be difficult to integrate directly, allowing independent optimization of each component while achieving functional integration.
2Device complexity
If a simple apparatus structure is used for modulation, then the device complexity is reduced, but the adaptability and versatility are limited without monolithic integration of modulation mechanisms
Solution Approach 1:
The light emitting device on the second substrate serves multiple functions: it acts as both the light source for modulation and the modulation mechanism itself. By positioning the light emitting device to irradiate the optical waveguide, it can modulate optical signals in the 1.55 µm band while maintaining a simple overall structure, achieving multi-functionality without complex integration.
3Device complexity
If the light emitting device is positioned on the back surface for simple structure, then the device complexity is reduced, but the optical coupling efficiency may be affected
Solution Approach 1:
The light emitting device is positioned on the back surface (second substrate) rather than directly on the waveguide, utilizing the third dimension (depth/layering) to achieve spatial separation. The optical coupling is maintained through precise alignment and the bonding interface, allowing simple structure while preserving optical efficiency through careful design of the bonding and positioning.
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
Enables efficient modulation of optical signals with a very simple apparatus structure, allowing for the propagation of light in the 1.55 µm band by using a light emitting device that absorbs light with a wavelength of 1.1 µm or below, effectively switching the optical signal on and off.
Implementation Method 1
The activation treatment at the step B in the method for manufacturing an optical waveguide apparatus according to the present invention is, e.g., a plasma treatment or an ozone treatment.
Implementation Method 2
The activation treatment at the step B in the method for manufacturing an optical waveguide apparatus according to the present invention is, e.g., a plasma treatment or an ozone treatment.
Implementation Method 3
the device that emits the light having the above-explained wavelength is provided on the back surface of the same, thereby enabling modulation of the optical signal
Data Source
AI summary
An optical waveguide apparatus having a very simple structure that can modulate a signal light guided through an optical waveguide is provided. A photoresist 13 is applied to an upper side of an SOI film 12, a photoresist mask 14 is formed, and the SOI film in a region that is not covered with the photoresist mask 14 is removed by etching to obtain an optical waveguide 15 having a single-crystal silicon core. Further, a light emitting device capable of irradiating the single-crystal silicon core with a light having a wavelength of 1.1 µm or below is provided on a back surface side of a quartz substrate 20 to provide an optical waveguide apparatus. When the light emitting device 30 does not apply a light, the light guided through the optical waveguide 15 is guided as it is. However, when the light emitting device 30 applies a light to form each pair of an electron and a hole in the irradiated region 16, the light guided through the optical waveguide 15 is absorbed by the pair of an electron and a hole, thereby enabling switching (modulation) for turning ON/OFF an optical signal depending on presence/absence (ON or OFF) of application of the light from the light emitting device 30.