Optical Signal Combining for Faster Photodetector Falling Time
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Solution Overview
Problem
Current photoelectric conversion devices have a longer falling time for output after pulse light irradiation, which hinders high-speed communication by not fully utilizing the responsiveness of the devices.
Innovation Solution
An optical detection device and signal processing method that combine the outputs from two photoelectric conversion elements, where the first and second outputs are irradiated with the same light pulse, with specific conditions ensuring a time position difference and sign difference in the amount of change until the peak, thereby shortening the falling time of the combined output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single photoelectric conversion element is used, then the device structure is simple, but the falling time of the output is long which limits high-speed communication
Solution Approach 1:
The patent divides a single photoelectric conversion element into multiple segments (first and second photoelectric conversion elements) that process the same light pulse independently. Each segment produces an output signal with different characteristics (different peak positions and change signs), and combining these segmented outputs achieves rapid falling time while maintaining structural simplicity
Solution Approach 2:
The patent merges the outputs from multiple photoelectric conversion elements through signal combination. By adding signals with opposite change signs and different peak positions, the combined output achieves rapid falling characteristics that neither individual element could achieve alone, resolving the contradiction between simple structure and fast response
2Speed
If multiple photoelectric conversion elements are used to shorten falling time, then the responsiveness is improved, but the device complexity increases
Solution Approach 1:
The patent segments the photoelectric conversion function across multiple elements, where each element processes the same light pulse to generate complementary output signals. This segmentation enables fast falling time through signal combination while keeping each individual element structurally simple
Solution Approach 2:
The patent utilizes parameter changes in the output signals from different photoelectric conversion elements, specifically the different peak positions and opposite change signs. By exploiting these parameter differences and combining the signals appropriately, the system achieves rapid falling time without requiring complex individual element structures
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 combined output from the optical detection device achieves a shorter falling time, enhancing the device's responsiveness and enabling more efficient high-speed communication by effectively utilizing the pulse light irradiation.
Implementation Method 1
The photodiode is, for example, a pn junction diode using a pn junction of a semiconductor, and converts light into an electrical signal
Data Source
AI summary
An optical detection device includes first photoelectric conversion element that outputs first output when first photoelectric conversion element is irradiated with light pulse, and second photoelectric conversion element that outputs second output when second photoelectric conversion element is irradiated with light pulse. The optical detection device is configured to combine first signal caused by first output and second signal caused by second output when first photoelectric conversion element and second photoelectric conversion element are irradiated with same light pulse each other, in a state where first condition and second condition are satisfied. The first condition is condition that time position of peak of first signal is different from time position of peak of second signal. The second condition is condition that sign of amount of change until the first signal reaches the peak is different from a sign of the amount of change until the second signal reaches the peak.