Novel optical fibre devices based on MCVD method

Abstract

In this thesis, several new optical fibre devices are described. These devices are based on fibres with special structures or materials, fabricated by the MCVD technique.
Light propagation and intermodal coupling in twin-core (TC) fibres are investigated both theoretically and experimentally. A cascaded TC fibre filter is demonstrated and so are TC fibre intermodal couplers using both mechanical gratings and fibre acoustic flexural waves, which can be used as filters, wavelength-division multiplexing (WDM) taps and frequency shifters.
Photosensitivity in both transition-metal-doped fibre and cerium-doped fibre with applications for making fibre in-core gratings are also studied. UV-induced absorption and refractive index change are investigated. A large absorption change occurs when fibre is exposed to pulsed UV. The fibre IR loss eventually recovers to its original level. The UV-induced refractive index change in cerium fibre is found to be the same order of magnitude as that reported in germanosilicate fibres.
Some other devices and effects, including a gold-implanted fibre polariser, excitation poling in second harmonic generation and a spatial model converter, are also studied. The gold-implanted polariser is much easier to be massproduced and spliced to an ordinary fibre with a low loss than its liquid-metal-implanted counterpart. Excitation poling gives an improved efficiency in second harmonic generation. The spatial model converter provides an easy low-loss connection for waveguides with different spatial modes.

More information

Identifiers

Catalogue record

Export record