The University of Southampton
University of Southampton Institutional Repository

Double-clad rare-earth doped fibre devices

Double-clad rare-earth doped fibre devices
Double-clad rare-earth doped fibre devices
This thesis reports on the exploitation of the cladding pumping technique to scale the output power of rare-earth (Er3+, Er3+/Yb3+, Yb3+, and Nd3+) doped fibre amplifiers and lasers, and on the study of alternative pumping schemes and applications.

In the first three chapters, the introduction of the cladding pumping scheme, its basic fibre geometries and fundamental analyses of double-clad fibres and their devices are presented.

Chapter 4 describes an investigation of various Er3+-doped and Yb3+ co-doped fibre devices. An Er3+/Yb3+-doped SM fibre amplifier pumped in the 820 nm band can not only avoid the excited state absorption (ESA) peaks of Er3+ at 800 and 840 nm, but also have a higher ratio of ground state absorption to ESA than that of Er3+ fibres. This enables a high gain amplifier with a much shorter fibre length. An experimental study of cladding pumped Er3+/Yb3+ fibres in amplifier and laser forms shows the simplicity of power scaling and brightness conversion from high-power large-area multimode laser diodes into a single diffraction-limited fibre mode, and thus scales the output powers. Efficient operation of a three-level Er3+-doped double-clad fibre in both laser and amplifier forms is described. The fibre design of a low area ratio of the inner cladding to the core reduces the threshold to an acceptable level.

The study of bending effects in large area ratio double-clad fibres indicates that a fibre having a concentric geometry can have nearly as high an efficiency as an eccentric core geometry if periodic bending is employed to promote mode scrambling. In contrast, double-clad fibres with eccentric cores and rectangular inner claddings were found to be relatively insensitive to bending.

In order to obtain high-peak-power pulsed sources, various kinds of novel pulsed fibre lasers have been investigated. These include a cladding pumped Nd3+ Q-switched fibre laser, an enhanced Q-switched double-clad fibre laser, a Q-switched Er3+ fibre laser double-clad fibre with a large mode-area core, and a picosecond mode-locked Yb3+fibre laser. Cladding pumped amplification of short pulses can extract high energy stored in doped fibres, thus obtain pulses with high peak power and energy.
Chen, Zhi-jie
d3c53120-7dd6-409c-b877-3edbddc00583
Chen, Zhi-jie
d3c53120-7dd6-409c-b877-3edbddc00583
Payne, David
4f592b24-707f-456e-b2c6-8a6f750e296d

Chen, Zhi-jie (1997) Double-clad rare-earth doped fibre devices. University of Southampton, Optoelectronics Research Centre, Doctoral Thesis, 197pp.

Record type: Thesis (Doctoral)

Abstract

This thesis reports on the exploitation of the cladding pumping technique to scale the output power of rare-earth (Er3+, Er3+/Yb3+, Yb3+, and Nd3+) doped fibre amplifiers and lasers, and on the study of alternative pumping schemes and applications.

In the first three chapters, the introduction of the cladding pumping scheme, its basic fibre geometries and fundamental analyses of double-clad fibres and their devices are presented.

Chapter 4 describes an investigation of various Er3+-doped and Yb3+ co-doped fibre devices. An Er3+/Yb3+-doped SM fibre amplifier pumped in the 820 nm band can not only avoid the excited state absorption (ESA) peaks of Er3+ at 800 and 840 nm, but also have a higher ratio of ground state absorption to ESA than that of Er3+ fibres. This enables a high gain amplifier with a much shorter fibre length. An experimental study of cladding pumped Er3+/Yb3+ fibres in amplifier and laser forms shows the simplicity of power scaling and brightness conversion from high-power large-area multimode laser diodes into a single diffraction-limited fibre mode, and thus scales the output powers. Efficient operation of a three-level Er3+-doped double-clad fibre in both laser and amplifier forms is described. The fibre design of a low area ratio of the inner cladding to the core reduces the threshold to an acceptable level.

The study of bending effects in large area ratio double-clad fibres indicates that a fibre having a concentric geometry can have nearly as high an efficiency as an eccentric core geometry if periodic bending is employed to promote mode scrambling. In contrast, double-clad fibres with eccentric cores and rectangular inner claddings were found to be relatively insensitive to bending.

In order to obtain high-peak-power pulsed sources, various kinds of novel pulsed fibre lasers have been investigated. These include a cladding pumped Nd3+ Q-switched fibre laser, an enhanced Q-switched double-clad fibre laser, a Q-switched Er3+ fibre laser double-clad fibre with a large mode-area core, and a picosecond mode-locked Yb3+fibre laser. Cladding pumped amplification of short pulses can extract high energy stored in doped fibres, thus obtain pulses with high peak power and energy.

PDF
ChenZ_1998_thesis_1220T.pdf - Other
Restricted to Repository staff only

More information

Published date: March 1997
Organisations: University of Southampton, Optoelectronics Research Centre

Identifiers

Local EPrints ID: 394562
URI: https://eprints.soton.ac.uk/id/eprint/394562
PURE UUID: c5441f80-9c45-4ecc-8fa9-cf2cfec91f9c

Catalogue record

Date deposited: 21 Jun 2016 14:29
Last modified: 17 Jul 2017 18:59

Export record

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of https://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×