“…Recently, various sensing materials have been applied to functionalize microfiber for highly sensitive sensors, such as graphene [16,17], carbon nanotubes [18,19], and quantum dots [20]. Particularly, graphene, as two-dimensional material, has excellent properties including surface plasmon polariton (spp) effect and fast thermal response, and has been emerged in many optical applications, such as optical polarizers and modulators [21][22][23]. Yet, no report has addressed graphene functionalized on the microfiber surface that produced from three or more twisted SMFs.…”