Reduction of Temperature Drift in Refractive-Index-Sensing Optical Frequency Comb by Active-Dummy Compensation of Dual-Comb Configuration

Refractive-index (RI) sensing plays a pivotal role in various domains, encompassing applications like glucose sensing, biosensing, and gas detection. Despite the advantages of optical fiber sensors, such as their compact size, flexibility, and immunity to electromagnetic interference, they are often plagued by temperature-induced drift, which adversely impacts the accuracy of RI measurements. This study introduces an innovative approach to alleviate temperature-induced drift in RI-sensing optical frequency combs (OFCs) by employing active-dummy compensation. The central idea revolves around the utilization of a dual-comb setup, comprising an active-sensing OFC that monitors both sample RI and environmental temperature, and a dummy-sensing OFC that exclusively tracks environmental temperature. The disparity between these sensor signals, denoted as
Δf_rep
, effectively nullifies the effects of temperature variations, yielding a temperature-independent sensor signal for precise RI measurements. This investigation delves into the relationship between active-dummy temperature compensation and
Δf_rep
. It becomes evident that diminishing
Δf_rep
values enhance temperature compensation, thereby diminishing fluctuations in
Δf_rep
caused by environmental temperature shifts. This compensation technique establishes a direct link between
Δf_rep
and sample RI, paving the way for absolute RI measurements based on
Δf_rep
. The findings of this research are a valuable contribution to the advancement of accurate and temperature-compensated RI sensing methodologies using dual-comb setup. The insights gained regarding
Δf_rep
dependency and the strategies proposed for enhancing measurement precision and stability hold significant promise for applications in fields of product quality control and biosensing.