Conventional spectral imaging systems use a set of predetermined filters to capture multi-band images. Liquid crystal tunable filters (LCTF) and active illumination allow reconfiguration of spectral sensitivities but these techniques have shortcomings such as latency due to multiple captures and the fact that the same filtering or illumination is applied to the whole frame of the image. There a...

We report on a wavelength-tunable filter based on multimode interference (MMI) effects. A typical MMI filter consists of a multimode fiber (MMF) spliced between two single-mode fibers (SMF). The peak wavelength response of the filter exhibits a linear dependence when the length of the MMF is modified. Therefore a capillary tube filled with refractive-index-matching liquid is used to effectively...

A new tunable electro-optical and thermal-optical modulator based on a liquid crystal (LC) filled side hole fiber (SHF) in ring laser (FRL) system has been proposed experimentally demonstrated. The LC is penetrated into the air of SHF, refractive index (RI) will be altered when an external electrical field or temperature difference applied due to effects electro-optic effects. SHF used as both ...