Fused coupler, an all-fiber passive branching component plays a key role in fiber optic communication network for light branching/splitting, wavelength multiplexing/ de-multiplexing, filtering, polarization selective splitting etc. [1,2]. The fabrication of fused-coupler has been achieved using several methods namely, Flame fusion, Optical irradiation etc.  and the technology is fully developed. However, an already fabricated fused coupler having a fixed power-splitting ratio at a particular wavelength cannot be achieved for any other wavelength unless the coupling segment gets reformed. In this research, we developed a dynamic light-coupling circuit by chemically etching a pair of twisted, identical SMF-28 fibers and tuning their coupling ratio by dipping the segment into a liquid with variable refractive indices (RI). The performance of such devices in terms of twisted length, number of turns and the excitation wavelength has also been investigated.
© 2019 Japan Society of Applied Physics, The Optical Society (OSA)PDF Article