Optical Module Wiring Part Covers Mesa Side Surface to Suppress Noise
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In optical communication devices, light reflection on the light-receiving element's surface generates noise, and existing solutions like offsetting or inclining the element lead to image distortion and reduced light reception sensitivity, especially in high-speed systems requiring smaller light receiving area diameters.
Innovation Solution
The optical module design includes a light-receiving element with a mesa part and a wiring part that covers the side surface, positioned based on the intensity distribution of the optical signal, allowing the wiring part to be aligned along the longitudinal direction of elliptical intensity distribution or the inclination direction of the light-receiving element, which reduces noise and maintains light reception sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the light-receiving element is disposed to deviate from the center of the optical axis of the lens, then noise due to light reflection is suppressed, but image distortion occurs and light reception sensitivity is reduced
Solution Approach 1:
The patent applies this principle by extending the wiring part from the two-dimensional electrode pattern onto the three-dimensional side surface of the mesa part. This dimensional transition allows the wiring part to cover the reflected light path in space, preventing it from entering the active area while maintaining proper light coupling to the absorption layer.
2Object-affected harmful factors
If the light-receiving element is disposed to incline the normal direction on the light reception surface with respect to the optical axis of the lens, then noise due to light reflection is suppressed, but the light beam becomes elliptical and image distortion occurs
Solution Approach 1:
The patent applies this principle by creating different functional zones on the light-receiving element surface. The wiring part is selectively positioned to cover only the regions where reflected light occurs, while leaving the central active area unchanged for optimal light reception. This localized approach suppresses noise without distorting the overall light beam shape.
3Speed
If the light receiving area diameter is decreased to reduce junction capacity for high speed transmission, then response time is improved, but coupling efficiency of incident light is reduced
Solution Approach 1:
The patent applies this principle by using the wiring part as an intermediary structure that serves dual functions: it collects electrical signals from the electrode while simultaneously acting as a physical barrier to block reflected light. This intermediary structure enables the use of smaller light receiving areas for high-speed transmission without sacrificing coupling efficiency, as the wiring part compensates for potential light loss by redirecting reflected light into the active area.
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 design effectively suppresses noise generation while maintaining or improving light reception sensitivity by broadening the permissible range of the light receiving area diameter, enhancing coupling efficiency and absorption of light within the intended area.
Implementation Method 1
a light absorption semiconductor layer that absorbs an optical signal entering from a light reception surface
Implementation Method 2
a lens configured to condense an optical signal from an optical fiber onto the light reception surface of the at least one light-receiving element
Data Source
AI summary
An optical module includes a light-receiving element configured to convert an incident optical signal to an electric signal. The light-receiving element includes a mesa part configured to laminate at least a first semiconductor layer, a light absorption semiconductor layer that absorbs an optical signal entering from a light reception surface, and a second semiconductor layer. The light-receiving element also includes an electrode part disposed on a top of the mesa part and a wiring part that covers a part of a side surface of the mesa part. The optical module includes a lens configured to condense an optical signal from an optical fiber onto the light reception surface. The wiring part is disposed at a position based on an intensity distribution of the optical signal on the light reception surface.