Glucose sensor with a Sagnac interference optical system

Abstract

The angle of optical rotation was measured by detecting the phase difference between clockwise and counterclockwise circular polarized light that propagated in a sensing loop. This polarimeter, or glucose sensor, consisted of a Sagnac interference optical system with a polarization-maintaining optical fiber, so it was not affected by the control limitations of the polarization rotation angle or the optical power fluctuation that occurs with scattered light, reflection, or polarization rotation in an optical system. The angle of rotation was measured from the phase difference of the glucose sensor when the concentration of glucose was changed. We confirmed that the resolution of optical rotation was 5×10(-4) deg, and the resolution of the glucose concentration was 1 mg/dl accordingly. The measured specific rotation of glucose was mostly equal to a physical property value. One applications of this glucose sensor is in measuring the blood sugar levels of diabetic patients.

Accurate optical rotation measurement by using spatial polarization modulation and digital image processing

“…The manuscript is devoted to solving the first difficulty, which is to realize the measurement of weak optical rotation signals. Many methods have been developed to measure weak optical signals, including the optical heterodyne method [4,5] , Faraday modulation method [6,7] , Sagnac interferometer method [8] , and self-referencing method [9,10] etc.. Among them, the optical system of the self-referencing method is accurate and simple.…”

Tricore photonic crystal fibre based refractive index sensor for glucose detection

“…Several authors have reported various forms of glucose sensor using both conventional and crystal fibres. In [24], Binu et al has proposed the fibre optic glucose sensor to sense the RI variation of different glucose concentration (5-25 g) present in the 100 ml distilled water with the experimental demonstration and Tatsuya Kumagai et al [25] has proposed an optical system to sense the glucose of 1 mg/dl resolution for human blood using polarisation maintain principle following the sagnac principle. Further, the sensing mechanism of glucose has been utilised with the help of PCF to produce the high average spectral compact sensitivity where biological liquid of any analyte is infiltrated [26] into any one of micro air hole claddings.…”

Controlling group and phase velocities in bidirectional mode-locked fiber lasers

“…Fiber technology is traditionally used for sensing applications, where a phase shift is measured either in a resonator or through evanescent wave coupling in a tapered fiber. For instance, Sagnac interference in an optical system consisting of a fiber loop with counter-propagating light beams can be used for rotation, temperature, tension, magnetic field sensing [1,2,3] and medical applications [4]. Michelson and Fabry-Perot interferometers are also used for temperature sensing [5,6].…”