[21p-E204-1~6] 3.14 Optical control devices and optical fibers

▲ [21p-E204-6] Ultra-high Sensitive and Broadband Inline Photodetector by Integrating Graphene onto Optical Fiber

〇(M2)Linqing Zhuo¹, Zhe Chen¹, Wenguo Zhu¹, Jianhui Yu¹ (1.Jinan Univ.)

Keywords:photodetectors, nanomaterials

Based on evanescent wave theory, we fabricate an inline graphene photodetector (IGPD) from visible to infrared regime. Unlike the pure graphene photodetector reported earlier, the IGPD achieves ultra-high responsiveness (1.5*10⁷ A/W) in our particular structure. We increase the absorption by spinning a hybrid polybutadiene(PB)/polymethyl methacrylate (PMMA) film over the graphene, at the same time the thermo-electricl effects were introduced. The refractive index of hybrid PB/PMMA film is about 1.49, which is larger than the fiber core. Via light propagation theory, light always travels towards a medium with a high refractive index, therefor, the PB/PMMA film drag the evanescent field out of fiber core. Most of the light field was confined below the hybrid film after leakage from the core, which greatly enhanced the interaction with graphene and increased the absorption rate from 2.3% to 72.13%. In addition, the influence of residual thickness of the side-polished region and wavelength of the incident light, on the IGPD sensitivity is investigated in detail. At the wavelength of 1550 nm, our device possesses a ultra-high responsivity of 1.5*10⁷ A/W and a fast response time of ~ 61.8 ms. In addition, our device is sensitive to a broad wavelength range from visible to near-infrared. This simple, sensitive, and easy-to-integrate graphene photodetecor provides us with ideas for the development of all fiber electrooptical devices.