In this thesis,kinds of novel fiber-optic chemo- and bio- sensors based on mode-filtered light detection (MFLD) were presented,originating from the proposition of MFLD mechanism. The term of mode-filtered light refers to the observation that light initially propagating down an optical fiber can be decoupled from that fiber by increasing the cladding RI at the core/clad interface with a permeating analyte,thus changing the allowable propagating modes within the fiber,resulting in a continuous and ...