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Title: Post-processing of photonic crystal fibres and standard fibres
Author: Witkowska, Agata
ISNI:       0000 0004 2673 6702
Awarding Body: University of Bath
Current Institution: University of Bath
Date of Award: 2009
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This thesis describes work on fibre transitions made in photonic crystal fibres (PCF) and conventional standard fibres. Three post-processing techniques were used to make the transitions: fibre tapering, ferrule drawing and a new technique – PCF hole inflation. All these methods change the fibre dimensions on a centimeter scale while maintaining very low loss. In the hole inflation technique, cladding holes are pressurized and can be enlarged while heat-treating, unlike other techniques where the holes can only be reduced in size. Controlled hole expansion was used to produce devices for applications such as supercontinuum generation. Furthermore, differential pressurization of holes could create a diversity of core shapes in a PCF section. For example they were investigated to improve interfacing of laser diodes to fibres. Differential pressurization was also used to introduce new cores into PCFs. Introducing a larger core asymmetrically by the original core resulted in a fundamental to second-order mode conversion with a high extinction ratio. Alternatively, similar mode conversion was demonstrated by fusing two unequal standard fibres. Also with standard fibres, low-loss multimode to single-mode fibre transitions were made using a modified fibre fabrication technique. These fibre transitions and optical devices have a wide range of potential applications, for example in supercontinuum generation and low-loss interfacing of fibres to other optical systems.
Supervisor: Birks, Timothy Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Optical fibres ; processing ; optical couplers