Temperature-controlled transformation in fiber types of fluid-filled photonic crystal fibers and applications.

We investigated experimentally and theoretically an invertible fiber-type transformation from a photonic bandgap fiber into a nonideal waveguide and then into an index-guiding photonic crystal fiber via the thermo-optic effect of the fluid filled in the air holes. Such a transformation could be used to develop an in-fiber optical switch/attenuator with a high-extinction ratio of more than 35 dB over an extremely broad wavelength range from 600 to 1700 nm via a small temperature adjustment.

Improved bending property of half-filled photonic crystal fiber.

A half-filling technique was demonstrated to improve the bending properties of a fluid-filled photonic crystal fiber. Such a technique can realize to fill selectively a fluid into half of air holes in a PCF. The bending properties of the half-filled PCF are quite different from those of the fully-filled PCF. Distinct bending properties were observed when the half-filled PCF was bent toward different fiber orientations. Especially, the transmission spectrum of the half-filled PCF was hardly affected while the fiber was bent toward the filled-hole orientation.

Generation of continuously wavelength-tunable optical short pulses by use of two self-seeded Fabry-Perot laser diodes and an optical switch.

Generation of wavelength-tunable optical short pulses by use of two self-seeded Fabry-Perot laser diodes in a parallel configuration is described. The system supports continuous wavelength tuning in a relatively wide range of 42 nm. The side-mode suppression ratio achieved is 35 dB across the entire wavelength tuning range. The system is convenient for continuous wavelength tuning.