Photon Detection Using Avalanche Photodiodes With Different Threshold Voltages
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing single-photon detection devices face challenges in detecting weak optical signals due to difficulties in distinguishing avalanche signals from capacitive response signals, leading to inefficient detection of photons, especially when the avalanche signal is not larger than the capacitive response signal.
Innovation Solution
A photon detection device comprising a first and second light-reception part with different breakdown voltages, where the gate signal is maintained at specific voltages for active and non-active time periods, and a determination part combines inverted and non-inverted signals to differentiate between photon reception and capacitive response signals, ensuring accurate detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single avalanche photodiode is used to detect weak optical signals, then the device structure is simple, but it becomes difficult to distinguish avalanche signals from capacitive response signals when the avalanche signal is not larger than the capacitive response signal
Solution Approach 1:
The single avalanche photodiode is divided into two separate avalanche photodiodes with different breakdown voltages. The first APD operates at a higher voltage to detect weak signals, while the second APD operates at a lower voltage to provide a capacitive response reference. This segmentation allows the system to maintain structural simplicity while improving signal distinction accuracy through differential measurement.
Solution Approach 2:
The invention changes the operating parameters by applying different voltages to two avalanche photodiodes. The first APD is biased above its breakdown voltage to generate avalanche signals, while the second APD is biased below its breakdown voltage to generate only capacitive response signals. This parameter differentiation enables the system to distinguish between actual photon-induced avalanche signals and capacitive artifacts.
2Reliability
If the avalanche photodiode operates in Geiger mode to detect single photons, then the detection sensitivity is improved, but false detection increases due to difficulty in distinguishing avalanche signals from capacitive response signals
Solution Approach 1:
The second avalanche photodiode acts as an intermediary that generates a capacitive response signal serving as a reference or mediator for comparison. By introducing this intermediate reference signal, the system can distinguish authentic avalanche signals from false capacitive responses, thereby maintaining high detection sensitivity while improving signal authenticity verification.
Solution Approach 2:
The determination unit compares the output signals from both avalanche photodiodes and uses this feedback mechanism to identify genuine avalanche signals. When the first APD produces a signal that matches the capacitive response pattern from the second APD, it indicates a false detection. This feedback-based discrimination improves measurement precision without sacrificing the high sensitivity of Geiger mode operation.
3Ease of operation
If a single avalanche photodiode is used, then the device is easy to operate, but detection efficiency is reduced when avalanche signals are comparable to capacitive response signals
Solution Approach 1:
The detection function is segmented into two parallel channels: one for signal generation (first APD) and one for reference generation (second APD). This segmentation enables the system to maintain ease of operation with a straightforward parallel architecture while dramatically improving photon detection efficiency through differential signal processing that eliminates capacitive response interference.
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 enables high photon-detection efficiency by effectively distinguishing between avalanche and capacitive response signals, reducing noise and after-pulse noise, and enhancing the reliability of photon detection.
Implementation Method 1
When the avalanche photodiode of the single-photon detection device operates in a Geiger mode, an avalanche signal may be generated by the avalanche photodiode
Implementation Method 2
a determination part configured to determine whether a photon is received, based on the first signal received from the first light-reception part and the second signal received from the second light-reception part
Data Source
AI summary
A photon detection device having a high light detection efficiency. The photon detection device includes a first light reception part which receives a gate signal and outputs a first signal; a second light reception part which receives a gate signal and outputs a second signal; and a determination part which determines whether or not a photon is received, on the basis of the first signal from the first light reception part and the second signal from the second light reception part. The photon is incident on the first light reception part among the first light reception part and the second light reception part, and the breakdown voltage of the second light reception part is higher than the breakdown voltage of the first light reception part.