摘要： In this paper, a D-shaped optical fiber is presented in terms of sensor application using FiberBench rotating wave plate. The designed sensor was adopted to detect plumbum ions in aqueous medium using surface plasmon resonance (SPR). The fiber-based SPR sensor was designed using a bilayer sensor chip. The polished area of the D-shaped optical fiber was coated by reduced graphene-based maghemite nanocomposite+1-ethyl-3-(3-dimethylaminopropyl)-carbodiimidehydrochloride/N-hydroxysuccinimide as a sensing layer. The transmission response curves were investigated according to the wavelength and intensity shifts at different concentrations. By incorporating the sensing layer, Pb2+ can be easily detected by wavelength and intensity interrogation methods. The sensor exhibited a recognizable intensity shift at 0.3 ppb Pb ion concentration. The limit of detection due to wavelength shift was 1 ppm. The sensitivity of the Pb ion concentration was 0.116 nm/ppm, and the accuracy was 19.1×10?4. FiberBench rotating wave plate was used to control the depth and the width of the transmission curve using SPR. The outcome of the developed sensor revealed a high accuracy, high sensitivity, and real-time sensor in a static water environment.