Harmonic femtosecond fiber laser based on supercontinuum generation with carbon nanotubes saturable absorber

An ultrashort pulse fiber laser has been proposed due to the problem of bulky size and high cost of the Titanium Sapphire laser and other commercial ultrashort pulse fiber lasers. Thus, this study focused on the development of a robust, compact and stable femtosecond mode-locked fiber laser via opti...

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Main Author:	Mat Rifin, Siti Norfarha
Format:	Thesis
Language:	English
Published:	2017
Subjects:	QC Physics
Online Access:	http://eprints.utm.my/id/eprint/79530/1/SitiNorfarhaMatRifinPFS2017.pdf
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spelling	my-utm-ep.795302018-10-31T12:58:09Z Harmonic femtosecond fiber laser based on supercontinuum generation with carbon nanotubes saturable absorber 2017 Mat Rifin, Siti Norfarha QC Physics An ultrashort pulse fiber laser has been proposed due to the problem of bulky size and high cost of the Titanium Sapphire laser and other commercial ultrashort pulse fiber lasers. Thus, this study focused on the development of a robust, compact and stable femtosecond mode-locked fiber laser via optical telecommunication components. This laser was designed to have a high repetition rate (80 - 100 MHz) and average output power (30 - 50 mW), and also a narrow pulse width (< 100 fs) which are crucial for a laser source used in all-fiber terahertz time domain spectroscopy system. A short cavity was needed in order to get a high repetition rate while the effect of optical dispersion in the cavity was included in order to produce a narrow pulse width. This design employed a passive mode-locked technique with a carbon nanotube thin film as the saturable absorber. Initially, a diode laser of 980 nm wavelength was used as a pumping source and a 0.4 m long of highly erbium-doped fiber with 110 dB/m peak absorption at wavelength of 1530 nm was utilised as a gain medium. Then, in order to achieve the desired parameters, the pump power was increased to raise the repetition rate of the pulse laser and a supercontinuum generation technique was adopted to compress the pulse width. The preliminary results of the designed laser show a fundamental repetition rate of 67.8 MHz at mode-locking threshold pump power of 63.5 mW. The average output power and pulse width obtained are 0.77 mW and 410 fs respectively. The increment of pump power to 104.2 mW significantly increased the fundamental repetition rate to 193.5 MHz which corresponds to the 3rd order harmonic and compressed the pulse width to 70 fs. The average output power after compressing the pulse width is 4.27 mW. As the conclusion, two of the targeted parameters of the laser have been successfully attained. This design however has not been able to produce the targeted average output power and to operate with the desired parameters simultaneously. 2017 Thesis http://eprints.utm.my/id/eprint/79530/ http://eprints.utm.my/id/eprint/79530/1/SitiNorfarhaMatRifinPFS2017.pdf application/pdf en public phd doctoral Universiti Teknologi Malaysia, Faculty of Science Faculty of Science
institution	Universiti Teknologi Malaysia
collection	UTM Institutional Repository
language	English
topic	QC Physics
spellingShingle	QC Physics Mat Rifin, Siti Norfarha Harmonic femtosecond fiber laser based on supercontinuum generation with carbon nanotubes saturable absorber
description	An ultrashort pulse fiber laser has been proposed due to the problem of bulky size and high cost of the Titanium Sapphire laser and other commercial ultrashort pulse fiber lasers. Thus, this study focused on the development of a robust, compact and stable femtosecond mode-locked fiber laser via optical telecommunication components. This laser was designed to have a high repetition rate (80 - 100 MHz) and average output power (30 - 50 mW), and also a narrow pulse width (< 100 fs) which are crucial for a laser source used in all-fiber terahertz time domain spectroscopy system. A short cavity was needed in order to get a high repetition rate while the effect of optical dispersion in the cavity was included in order to produce a narrow pulse width. This design employed a passive mode-locked technique with a carbon nanotube thin film as the saturable absorber. Initially, a diode laser of 980 nm wavelength was used as a pumping source and a 0.4 m long of highly erbium-doped fiber with 110 dB/m peak absorption at wavelength of 1530 nm was utilised as a gain medium. Then, in order to achieve the desired parameters, the pump power was increased to raise the repetition rate of the pulse laser and a supercontinuum generation technique was adopted to compress the pulse width. The preliminary results of the designed laser show a fundamental repetition rate of 67.8 MHz at mode-locking threshold pump power of 63.5 mW. The average output power and pulse width obtained are 0.77 mW and 410 fs respectively. The increment of pump power to 104.2 mW significantly increased the fundamental repetition rate to 193.5 MHz which corresponds to the 3rd order harmonic and compressed the pulse width to 70 fs. The average output power after compressing the pulse width is 4.27 mW. As the conclusion, two of the targeted parameters of the laser have been successfully attained. This design however has not been able to produce the targeted average output power and to operate with the desired parameters simultaneously.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Mat Rifin, Siti Norfarha
author_facet	Mat Rifin, Siti Norfarha
author_sort	Mat Rifin, Siti Norfarha
title	Harmonic femtosecond fiber laser based on supercontinuum generation with carbon nanotubes saturable absorber
title_short	Harmonic femtosecond fiber laser based on supercontinuum generation with carbon nanotubes saturable absorber
title_full	Harmonic femtosecond fiber laser based on supercontinuum generation with carbon nanotubes saturable absorber
title_fullStr	Harmonic femtosecond fiber laser based on supercontinuum generation with carbon nanotubes saturable absorber
title_full_unstemmed	Harmonic femtosecond fiber laser based on supercontinuum generation with carbon nanotubes saturable absorber
title_sort	harmonic femtosecond fiber laser based on supercontinuum generation with carbon nanotubes saturable absorber
granting_institution	Universiti Teknologi Malaysia, Faculty of Science
granting_department	Faculty of Science
publishDate	2017
url	http://eprints.utm.my/id/eprint/79530/1/SitiNorfarhaMatRifinPFS2017.pdf
_version_	1747818248810790912

Harmonic femtosecond fiber laser based on supercontinuum generation with carbon nanotubes saturable absorber

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