In this paper, we developed a fiber type system for glucose absolute concentration measurement that integrated a pair of fiber sensors and heterodyne interferometry. The pair of the fiber sensors was constructed of single mode fibers which immobilized the glucose oxidase (GOx) on the core. Our studies show that the response time and resolution will be highly affected by the pH properties between the testing sample and GOx of the fiber sensor. The best response time of the fiber sensor are 1.3 seconds for glucose solution as the pH values of testing solution and GOx of the fiber sensor are identical. In addition, the results show good linearity of the calibration curve for the glucose solution and serum based sample. The best resolutions are 0.141 and 0.152 mg/dl for glucose solution and serum based sample, respectively. Besides, the fiber sensor can be reused more than 10 times in this study.