Avalanche Photodiode Array Quenching Circuit for Lower Dead Time
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Avalanche photodiodes arranged on a semiconductor substrate face challenges in Geiger mode operation due to increased dark pulses and after pulses with temperature variations, leading to noise and reduced signal detection, with passive quenching elements requiring optimal resistance values to balance quenching and dead time, while also dealing with parasitic capacitance affecting pulse signals.
Innovation Solution
A photodetector device design featuring a separate circuit substrate with parallel-connected output units, including passive quenching and capacitative elements, reduces parasitic capacitance and allows for improved pulse signal detection by optimizing the resistance and capacitance values, enhancing photodetection sensitivity and time resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive quenching elements with larger resistance values are used to achieve appropriate quenching, then quenching effectiveness is improved, but dead time increases and photodetection time resolution deteriorates
Solution Approach 1:
The patent applies dynamic principle by making the quenching resistance variable rather than fixed. The switchable quenching resistance unit allows the resistance value to be dynamically adjusted between a first resistance value (for strong quenching) and a second resistance value (for reduced dead time), enabling the system to adapt to different operational requirements and resolve the contradiction between quenching effectiveness and time resolution
Solution Approach 2:
The patent segments the quenching resistance into multiple switchable units with different resistance values. Instead of using a single passive quenching element, the system divides the quenching function across multiple resistive elements that can be selectively activated, allowing optimization of both quenching performance and time resolution through appropriate selection of resistance values
2Device complexity
If passive quenching elements are integrated on the same substrate as avalanche photodiodes, then device complexity is reduced, but parasitic capacitance increases and affects pulse signals
Solution Approach 1:
The patent segments the device into functionally independent substrates: the avalanche photodiode array substrate for light detection and the separate quenching resistance unit substrate for signal processing. This physical segmentation effectively isolates the high-impedance photodetector elements from parasitic capacitances introduced by integrated circuit elements, while still maintaining a compact overall device structure through substrate stacking or close coupling
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 design secures photodetection accuracy and improves time resolution by reducing dead time and parasitic capacitance, allowing for efficient detection of light signals with a simple and effective circuit configuration.
Implementation Method 1
The capacitative element is connected in series to at least one of the avalanche photodiodes, and is connected in parallel to the passive quenching element
Implementation Method 2
A plurality of avalanche photodiodes are two-dimensionally arranged in the avalanche photodiode array substrate. The plurality of avalanche photodiode is arranged to operate in a Geiger mode
Data Source
AI summary
A photodetector device includes an avalanche photodiode array substrate formed from compound semiconductor. A plurality of avalanche photodiodes arranged to operate in a Geiger mode are two-dimensionally arranged on the avalanche photodiode array substrate. A circuit substrate includes a plurality of output units which are connected to each other in parallel to form at least one channel. Each of the output units includes a passive quenching element and a capacitative element. The passive quenching element is connected in series to at least one of the plurality of avalanche photodiodes. The capacitative element is connected in series to at least one of the avalanche photodiodes and is connected in parallel to the passive quenching element.