Optical fiber has been traditionally served as a passive transmission
medium in optical communications. For the past ten years, there have
been extensive research to exploit the potentials of optical fiber waveguides
as a functional building block to manipulate photons in a novel manner.
Hollow core fiber has been developed in FORlab with a three-layered structure,
silica clad, germano silica ring core, and air hole in the center, to find applicaitons
in novel photonic devices. In this presentation, three parts will be discussed
in terms of fabrication and design, photonic device applications, forefront research
ahead, along with an emphasis on mode conversion technlogy,
acousto-optic interaction, hybridization of liquid, gaseous active media.

Part of the presentation will be also given to the invited papers in the following
conferences; conference on optical fiber sensors(Japan), OSA annual meeting (USA),
IEEE-LEOS annual meeting(USA)