Avalanche Diode Bias Control for Stable Single-Photon Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing avalanche diode arrangements face challenges in efficiently controlling the excess bias voltage, leading to high power consumption and variability in single-photon detection performance due to temperature changes, which affects detection parameters like dark count rate, photon detection probability, and timing jitter.
Innovation Solution
An avalanche diode arrangement comprising a latch comparator and a quenching circuit that allows for dynamic control of the excess bias voltage by comparing the node voltage with a reference voltage, reducing power consumption through an enable signal that activates the comparator only during photon detection events, and using a digital control circuit to adjust the bias voltage based on measurement cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bias voltage of the avalanche diode is increased to improve single-photon detection performance, then the photon detection probability increases, but the power consumption increases and dark count rate increases
Solution Approach 1:
The patent implements periodic action by using a reset signal that periodically resets the avalanche diode after each detection event. The circuit operates in cycles: the diode is biased above breakdown voltage for photon detection, and when a photon is detected (indicated by voltage exceeding reference voltage), a reset signal is generated that lowers the bias voltage below breakdown voltage to stop the avalanche current. This periodic resetting allows the system to maintain high detection probability during active phases while reducing power consumption during reset phases, directly addressing the contradiction between detection performance and power consumption.
2Measurement precision
If the excess bias voltage is increased to improve detection sensitivity, then the timing jitter decreases, but the dark count rate increases due to temperature variability
Solution Approach 1:
The patent implements feedback by continuously monitoring the voltage at the first node and comparing it with a reference voltage using a comparator. When the monitored voltage exceeds the reference voltage (indicating a photon detection event), the comparator output triggers a reset signal that adjusts the bias voltage. This feedback mechanism allows the system to maintain optimal excess bias voltage for low timing jitter during active detection phases while automatically reducing the bias voltage to minimize dark count rate when no photons are present, thereby resolving the contradiction between timing precision and dark count suppression.
3Reliability
If the bias voltage is dynamically adjusted to maintain stable detection parameters across temperature changes, then the detection accuracy improves, but the circuit complexity increases
Solution Approach 1:
The patent implements self-service by designing a circuit that automatically adjusts its own bias voltage without requiring external temperature sensing or complex control systems. The avalanche diode's own voltage response to photon detection events is used to trigger reset signals that automatically modulate the bias voltage. This self-regulating mechanism maintains stable detection parameters across temperature changes while keeping the circuit relatively simple, as the system uses its intrinsic electrical characteristics rather than adding external temperature compensation circuitry.
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 low power consumption and stable single-photon detection by directly monitoring and adjusting the excess bias voltage, maintaining consistent detection parameters across varying temperatures, thus improving the accuracy and efficiency of the avalanche diode arrangement.
Implementation Method 1
When the photon hits the SPAD, an electron-hole pair is generated and a very high short current pulse is generated due to the very high electrical field
Implementation Method 2
When the photon hits the SPAD, an electron-hole pair is generated
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 2A~2C
AI summary
A avalanche diode arrangement comprises an avalanche diode (11) that is coupled to a first voltage terminal (14) and to a first node (15), a latch comparator (12) with a first input (16) coupled to the first node (15), a second input (17) for receiving a reference voltage (VREF) and an enable input (21) for receiving a comparator enable signal (CLK), and a quenching circuit (13) coupled to the first node (15).