Adaptive measurement method for miniature spectrometers used in cold environments.

Abstract

Adaptive measurement is a major concern when using miniature spectrometers in extreme environments, especially when the ambient temperatures and incident light intensities vary greatly. In this study, parameters, including the signal output and the relevant noise and signal-to-noise ratio (SNR) of a fiber optic spectrometry system composed of a photodiode array miniature spectrometer and external driver electronics were examined at multiple integration times from -50°C to 30°C, well below the specified operating temperature of this spectrometer. The relationships between those parameters and incident light level were also examined, at a single temperature of 0°C. Based on these examinations, temperature-induced biases in the linear operating range of the spectrometer were identified. Signal output and the relevant noise and SNR in response to different integration times, temperatures, and incident light levels were assessed separately. These assessments were then used to develop an adaptive measurement method for estimating the incident light level and setting up an optimal integration time for this spectrometer, while autonomously adapting the variation in the ambient temperature and incident light level simultaneously. This approach provides a general framework for developing an adaptive measurement algorithm for miniature spectrometers, which face tremendous variations in ambient temperature and incident light level.