Optical Receiver Module Electrode Capacitance Design
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Solution Overview
Problem
Existing optical receiver modules face challenges in achieving good frequency transmission characteristics when using preamplifiers with different input impedances, requiring different light receiving elements and increasing production costs and complexity.
Innovation Solution
The optical receiver module design incorporates a light receiving element with a preamplifier and an insulating carrier substrate, featuring electrodes with a capacitance value of 40 fF or more between them, allowing for the same light receiving element to be used with preamplifiers of varying input impedances by adjusting the capacitance value between electrodes on the carrier substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If different kinds of preamplifier ICs are used to satisfy linearity and high receiver sensitivity requirements, then performance requirements are met, but manufacturing cost increases and usability of semiconductor wafer deteriorates
Solution Approach 1:
The patent applies universality by designing a single preamplifier IC that can serve multiple functions - it can operate in different modes (linearity-optimized or sensitivity-optimized) depending on the operating conditions. This is achieved through a unified design that accommodates both requirements without needing separate preamplifier types, thereby improving manufacturing efficiency and reducing costs while meeting all performance requirements
2Use of energy by moving object
If the driving voltage is lowered to +3.3V for low power consumption, then power consumption is reduced, but it becomes difficult to design a preamplifier that satisfies both linearity and high receiver sensitivity
Solution Approach 1:
The patent applies parameter changes by optimizing the preamplifier design parameters specifically for the +3.3V single power source condition. Through careful selection and adjustment of circuit parameters (such as transistor sizing, bias currents, and impedance matching) within the constrained voltage range, the preamplifier achieves both linearity and high receiver sensitivity simultaneously, proving that parameter optimization can overcome voltage constraints
3Reliability
If different light receiving elements are used for preamplifiers with different input impedances, then frequency transmission characteristics are optimized, but production complexity increases and costs rise
Solution Approach 1:
The patent applies universality by designing a single light receiving element that can be used with preamplifiers having different input impedances. The element is designed with optimized parameters (such as capacitance and resistance values) that provide good frequency transmission characteristics across different preamplifier configurations, eliminating the need for multiple specialized light receiving elements and simplifying production
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 enables optimal frequency transmission characteristics for both high linearity and high sensitivity preamplifiers using the same light receiving element, reducing production costs and simplifying manufacturing processes.
Implementation Method 1
a light receiving element for receiving an optical signal to convert the same into an electrical signal
Implementation Method 2
providing two electrodes, on the carrier substrate, having a capacitance value of 40 fF (femtofarad) or more therebetween
Data Source
AI summary
A semiconductor chip on which a light receiving element is mounted, a preamplifier for amplifying an output signal from the light receiving element, and an insulating carrier substrate on which the light receiving element is mounted are connected such that the output signal from the light receiving element is input to the preamplifier through electrodes on the carrier substrate, and there are provided two electrodes, on the carrier substrate, having a capacitance value of 40 fF or more therebetween in a state where no light receiving element is mounted.