The University of Southampton
University of Southampton Institutional Repository

Ultra-low NA step-index large mode area Yb-doped fiber with a germanium doped cladding for high power pulse amplification

Ultra-low NA step-index large mode area Yb-doped fiber with a germanium doped cladding for high power pulse amplification
Ultra-low NA step-index large mode area Yb-doped fiber with a germanium doped cladding for high power pulse amplification
High concentration rare earth doped, large mode area (LMA) step-index fibers, which feature a very high cladding absorption per unit length at the pump wavelength, high efficiency, and excellent beam quality, are ideal for high power pulsed fiber lasers/amplifiers where large effective mode areas and short device lengths are crucial in order to reduce detrimental nonlinear effects associated with high peak power operation. In this Letter, we realize low numerical aperture (NA) high absorption fibers, simply by employing a germanium (Ge)-doped cladding rather than a pure silica cladding to offset the high refractive index associated with using a high concentration of ytterbium (Yb) in the core. This approach allows us to separate the two inter-linked fiber design parameters of pump absorption and NA in a step-index fiber. Using a conventional modified chemical vapor deposition process combined with solution doping, a low NA (0.04), LMA (475µm2) silica fiber is fabricated with a cladding absorption value of >20dB/m, which is the highest value among LMA step-index fibers with NA<0.06 so far reported to the best of our knowledge. The fabricated Yb-doped fiber was tested in a high-power picosecond amplifier system and enabled the generation of 190 ps laser pulses with a 101 µJ pulse energy and 0.5 MW peak power at an average power of 150 W.
0146-9592
3828-3831
Sidharthan, Raghuraman
c530dd79-017d-4d9b-a7d5-0b054e5c2c41
Lin, Di
d858c2c7-6eab-49d8-87e7-6b71d9bad013
Lim, Jang Jie
59668283-9624-4eed-ac5c-26557a34e284
Li, Huizi
fd7a494d-8a38-4d1f-b734-492897da9823
Lim, Serene Huiting
10f5e75b-0bbf-4bcd-a48d-345e359a3480
Chang, Chen Jian
1b1e147a-c68b-4bf7-8070-f5e1e1618456
Seng, Yue Men
3845ce7a-80b3-4a65-afe6-db45e52694d3
Chua, Song Liang
0d305f5f-2604-4f17-a141-a4454457aaae
Jung, Yongmin
6685e51e-be47-4c96-8c4b-65aee3b5126d
Richardson, David J.
ebfe1ff9-d0c2-4e52-b7ae-c1b13bccdef3
Yoo, Seongwoo
09689046-7e27-40c4-a205-0f26c93f527d
Sidharthan, Raghuraman
c530dd79-017d-4d9b-a7d5-0b054e5c2c41
Lin, Di
d858c2c7-6eab-49d8-87e7-6b71d9bad013
Lim, Jang Jie
59668283-9624-4eed-ac5c-26557a34e284
Li, Huizi
fd7a494d-8a38-4d1f-b734-492897da9823
Lim, Serene Huiting
10f5e75b-0bbf-4bcd-a48d-345e359a3480
Chang, Chen Jian
1b1e147a-c68b-4bf7-8070-f5e1e1618456
Seng, Yue Men
3845ce7a-80b3-4a65-afe6-db45e52694d3
Chua, Song Liang
0d305f5f-2604-4f17-a141-a4454457aaae
Jung, Yongmin
6685e51e-be47-4c96-8c4b-65aee3b5126d
Richardson, David J.
ebfe1ff9-d0c2-4e52-b7ae-c1b13bccdef3
Yoo, Seongwoo
09689046-7e27-40c4-a205-0f26c93f527d

Sidharthan, Raghuraman, Lin, Di, Lim, Jang Jie, Li, Huizi, Lim, Serene Huiting, Chang, Chen Jian, Seng, Yue Men, Chua, Song Liang, Jung, Yongmin, Richardson, David J. and Yoo, Seongwoo (2020) Ultra-low NA step-index large mode area Yb-doped fiber with a germanium doped cladding for high power pulse amplification. Optics Letters, 45 (14), 3828-3831. (doi:10.1364/OL.396157).

Record type: Article

Abstract

High concentration rare earth doped, large mode area (LMA) step-index fibers, which feature a very high cladding absorption per unit length at the pump wavelength, high efficiency, and excellent beam quality, are ideal for high power pulsed fiber lasers/amplifiers where large effective mode areas and short device lengths are crucial in order to reduce detrimental nonlinear effects associated with high peak power operation. In this Letter, we realize low numerical aperture (NA) high absorption fibers, simply by employing a germanium (Ge)-doped cladding rather than a pure silica cladding to offset the high refractive index associated with using a high concentration of ytterbium (Yb) in the core. This approach allows us to separate the two inter-linked fiber design parameters of pump absorption and NA in a step-index fiber. Using a conventional modified chemical vapor deposition process combined with solution doping, a low NA (0.04), LMA (475µm2) silica fiber is fabricated with a cladding absorption value of >20dB/m, which is the highest value among LMA step-index fibers with NA<0.06 so far reported to the best of our knowledge. The fabricated Yb-doped fiber was tested in a high-power picosecond amplifier system and enabled the generation of 190 ps laser pulses with a 101 µJ pulse energy and 0.5 MW peak power at an average power of 150 W.

Text
Manuscript-Optics Letters Final 20200427 - Accepted Manuscript
Restricted to Repository staff only until 6 July 2021.
Request a copy

More information

Accepted/In Press date: 28 May 2020
Published date: 6 July 2020

Identifiers

Local EPrints ID: 442348
URI: http://eprints.soton.ac.uk/id/eprint/442348
ISSN: 0146-9592
PURE UUID: 2d342a5c-eef9-48d5-9103-75bcc6401b13
ORCID for Di Lin: ORCID iD orcid.org/0000-0001-5025-9051
ORCID for David J. Richardson: ORCID iD orcid.org/0000-0002-7751-1058

Catalogue record

Date deposited: 14 Jul 2020 16:30
Last modified: 07 Oct 2020 02:08

Export record

Altmetrics

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 http://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.

×