This research focuses on the development of an interrogator that operates and measures fiber Bragg grating(FBG) multiplexing sensor probes for accurate-measurement of the blade deflection in a wind power generator. We designed and fabricated an optical source and spectrum module for the interrogator. Additionally, we verified the wavelength repeatability within 0.001 nm and the wavelength stability within 1 pm of the optical source, and we experimentally determined that the wavelength scanning range was about 44.4 nm. The FBG sensor with 2 nm resolution can be extended to a performance-efficient system that measures more than 20 sensors. The implemented interrogator has 0.141 nm wavelength variations corresponding to an ambient temperature range of $0^{circ}C$ to $70^{circ}C$. The measurement error can be easily reduced by employing a temperature compensation algorithm. In this study, we quantitatively confirmed the accuracy and operating stability of the interrogator.