Photodetector Array Temperature Sensing via Dark Current
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Solution Overview
Problem
Conventional photodetector arrays face accuracy issues due to temperature changes, as existing temperature sensing methods, such as discrete temperature sensors or using the readout integrated circuit (ROIC) temperature, are less than optimal.
Innovation Solution
Incorporating a photodetector array with aggregate dark current that is DC coupled to eliminate photonic transient events and using the temperature coefficient of the dark current to sense temperature, which is then processed by circuitry, including a readout integrated circuit (ROIC), to enhance accuracy and adjust bias voltage accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If discrete temperature sensors or ROIC temperature sensing is used, then temperature sensing is provided, but measurement precision is insufficient
Solution Approach 1:
The photodetector array performs self-temperature sensing by utilizing its own dark current signal. The system extracts temperature information from the dark current generated by the photodetector pixels themselves, eliminating the need for separate temperature sensors. This self-service approach improves measurement precision while maintaining reliability, as the temperature sensing is performed by the detector array's inherent electrical characteristics rather than external components.
2Measurement precision
If aggregate dark current is used for temperature sensing, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The readout circuitry serves dual functions: it reads out the photonic signal from the detector array and simultaneously measures the dark current for temperature sensing. By integrating temperature sensing capabilities into the existing readout circuit, the system achieves high measurement precision without adding significant device complexity. The same circuit infrastructure is utilized for both primary detection and temperature monitoring functions.
Solution Approach 2:
The patent combines temperature sensing functionality with the photodetector array's existing readout circuitry. The dark current measurement path is integrated into the standard signal readout path, allowing temperature information to be extracted alongside photonic data. This merging of functions improves measurement precision while avoiding the complexity of separate dedicated temperature sensing circuits.
3Device complexity
If photonic transient events are included in dark current measurement, then measurement is simpler, but measurement precision deteriorates
Solution Approach 1:
The system extracts and removes photonic transient events from the dark current measurement by using AC coupling or high-pass filtering techniques. This extraction separates the temperature-related DC component from the photonic signal components, allowing accurate temperature sensing without being contaminated by transient photonic events. The filtering approach maintains measurement precision while managing the complexity of signal processing.
Solution Approach 2:
The patent introduces filtering circuitry as an intermediary between the photodetector output and the temperature measurement system. This intermediary component selectively removes photonic transient events while preserving the dark current signal containing temperature information. The filter acts as a mediator that cleans the signal before temperature extraction, improving measurement precision with manageable added complexity.
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 approach provides accurate temperature sensing and feedback for temperature control, improving the performance and reliability of photodetector arrays by filtering out high-frequency photonic input signals and background noise, allowing for precise temperature determination and adjustment.
Implementation Method 1
using the temperature coefficient of the dark current to sense temperature
Implementation Method 2
filtering out high-frequency photonic input signals and background noise
Data Source
AI summary
Methods and apparatus for temperature sensing in a detector system. Dark current from pixels in a pixel array of the detector system can be filtered to remove noise and processed to determine a temperature of the pixel array from the filtered dark current. Calibration of the dark current for a range of temperatures can be performed. In embodiments, the pixels comprise photodiodes.