Flat-plate Light-receiving Package for Stable Optical Monitoring
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Solution Overview
Problem
Conventional monitor PDs in optical modules face challenges with increased module size due to fiber arrangement and unstable reception sensitivity, especially when exposed bare chips receive stray light and vary with mounting accuracy.
Innovation Solution
A light-receiving package with a photo diode and retaining holder, combined with a rectangular U-shaped concave holder and flat-plate base, allows for adjustable placement on a substrate, ensuring constant reception sensitivity without module size increase, using a waveguide type optical element to guide light and separate signal from stray light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the monitor PD is connected to the middle of the optical fiber by fusion bonding, then the optical signal can be monitored, but the entire module size increases and fiber arrangement becomes difficult
Solution Approach 1:
The patent extracts the monitor PD from the traditional fiber fusion bonding structure and relocates it to the end face of the optical module. This allows the monitor PD to receive optical signals directly from the optical fiber end face without requiring fusion bonding connections in the middle of the fiber, thereby reducing module size and simplifying fiber arrangement while maintaining monitoring capability
Solution Approach 2:
The patent introduces a lens as an intermediary component between the optical fiber end face and the monitor PD. The lens focuses the optical signal from the fiber onto the monitor PD, enabling effective monitoring without direct contact or fusion bonding, thus avoiding the space requirements and complexity of traditional fusion bonding structures
2Device complexity
If the PD bare chip is exposed inside the optical module, then integration is achieved, but stray light is received along with the main optical signal making stable monitoring difficult
Solution Approach 1:
The patent applies local quality by positioning the monitor PD at a specific location (end face of the optical module) where it can selectively receive optical signals while avoiding stray light sources. The lens is positioned to create a focused reception area that discriminates between the main optical signal and stray light, improving monitoring stability while maintaining integration
Solution Approach 2:
The patent converts the potential harm of stray light by using the lens to focus only the desired optical signal onto the monitor PD while blocking or excluding stray light paths. This transforms the challenging environment inside the optical module into a controlled reception zone where the monitor PD can accurately detect signals despite the presence of other light sources
3Ease of manufacture
If the monitor PD is implemented without adjustment, then manufacturing is simplified, but reception sensitivity varies depending on mounting accuracy
Solution Approach 1:
The patent applies preliminary action by pre-positioning the monitor PD and lens at predetermined locations during the manufacturing process. The lens is mounted in a fixed position relative to the monitor PD, creating a predetermined optical path that ensures consistent reception sensitivity without requiring complex adjustment procedures during assembly or installation
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
The solution stabilizes reception sensitivity and reduces stray light interference, enabling accurate monitoring of optical signals without enlarging the module, ensuring consistent performance.
Implementation Method 1
an optical module which is provided with a waveguide type optical element which is mounted on the substrate and guides light from an optical fiber and the light-receiving package for flat-plate mounting of the present invention which receives monitor light emitted from the waveguide type optical element after separation of a portion of light propagating through the waveguide type optical element
Implementation Method 2
a light-receiving package for flat-plate mounting which is mounted with a monitor PD (PhotoDiode)
Data Source
AI summary
A light-receiving package for flat-plate mounting which can make monitor reception sensitivity of an optical signal constant without increasing the size of a module. The light-receiving package for flat-plate mounting is provided with a first subassembly in which a photo diode is fixed to a front surface of a retaining holder, a back surface of the retaining holder is a flat surface capable of moving parallel on a plane parallel to a light-receiving surface of the photo diode and a second subassembly which has a rectangular U-shaped concave holder for retaining the retaining holder, and a flat-plate base disposed on a substrate and in which a surface of the flat-plate base that is mounted on the substrate is a flat surface capable of moving parallel to a substrate surface, the rectangular U-shaped concave holder and the flat-plate base are fixed, at least one of surfaces of the concave holder having a rectangular U-shape being a flat surface is a flat surface capable of moving parallel to the back surface of the retaining holder.