NDLI: High-power Yb- and Tm-doped fiber amplifiers seeded by a femtosecond Er:Fiber system

Content Provider	IEEE Xplore Digital Library
Author	Kumkar, S. Wunram, M. Storz, P. Fehrenbacher, D. Brida, D. Leitenstorfer, A.
Copyright Year	2013
Description	Author affiliation: Dept. of Phys., Univ. of Konstanz, Konstanz, Germany (Kumkar, S.; Wunram, M.; Storz, P.; Fehrenbacher, D.; Brida, D.; Leitenstorfer, A.)
Abstract	Summary form only given. The generation of ultrafast optical pulses that are used for many applications is increasingly based on Er:fiber lasers. The inherent advantages of this technology are compactness, stability, and turn-key operation. Tm- and Yb-doped fiber systems are promising candidates for reaching microjoule pulse energies [1,2,3].We present a setup exploiting the well-established Er:fiber technology that provides a femtosecond pulse train suitable for coherent seeding of both Yb: and Tm:amplifiers. A seed source generates pulses with a wavelength centered at 1550 nm. Four parallel amplification branches each provide 8 nJ pulse energy at a repetition rate of 40 MHz. This source implements also a passive phase-locking scheme [4]. The pulses are compressed in a silicon prism pair and then coupled into a highly nonlinear fiber (HNF). This scheme allows us to generate tailor-cut spectra with components spanning from 800 to 2300 nm that can be finely tuned by material insertion in the prism sequence [5]. The solitonic part of the spectrum is centered at 1970 nm and optimized to cover the entire gain bandwidth of Tm:silica. The dispersive part of a second HNF is designed to fit the gain maximum of Yb-doped fibers at a wavelength of 1030 nm. The benefit of Er:fiber seeding has been proven experimentally by confirming the full coherence of the spectral components generated in the HNFs [6].MHz and the transform limit for the pulse duration is 110 fs. The Er:fiber system acts as seed source for the parallel Yb: and Tm:fiber amplifiers. We reduce the repetition rate to 10 MHz via electro-optic modulators. To amplify the spectrum delivered by the HNF at a center wavelength of 1030 nm, we stretch the pulses with a grating pair to a temporal duration of 340 ps. The amplification occurs in a first Yb:fiber preamplifier pumped at a wavelength of 976 nm. The energy is then boosted in a 1.5 m long Yb-doped photonic crystal fiber (PCF) amplifier stage. The PCF double cladding structure enables pumping with high-power multimode laser diodes. At a pump power of 40 W, we measured pulse energies of 2.2 μJ. The spectrum after amplification has a bandwidth of 12 nm (FWHM) centered at 1032 nm (see Fig. 1.a). Recompression of these pulses leads to a pulse duration of 185 fs (see SHG FROG characterization in Fig. 1.b). The seed for the Tm:amplifier is stretched in 30 m of single-mode fiber directly spliced to the HNF. In a monolithic and truly single-mode Tm:fiber amplifier pumped at 796 nm, we demonstrate pulse energies of 250 nJ at a repetition rate of 10 MHz [6]. Fig. 1.c shows the pulse spectrum after amplification. It is centered at a wavelength of 1950 nm with a bandwidth of 50 nm. Both amplifiers are operating in a linear regime and there are no signs of a significant influence of nonlinear effects. The combination of high-energy, sub 200-fs pump pulses together with passive carrier-envelope phase stability of ultrabroadband seed pulses for parametric amplification paves the way towards extremely nonlinear optics and attosecond technology at unprecedented repetition rates and stability.
Sponsorship	Eur. Phys. Soc.
Starting Page	1
Ending Page	1
File Size	280572
Page Count	1
File Format	PDF
e-ISBN	9781479905942
DOI	10.1109/CLEOE-IQEC.2013.6801344
Language	English
Publisher	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Publisher Date	2013-05-12
Publisher Place	Germany
Access Restriction	Subscribed
Rights Holder	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Subject Keyword	Optical fiber amplifiers Optimized production technology Bandwidth Laser stability Ultrafast optics Optical fiber dispersion Fiber lasers
Content Type	Text
Resource Type	Article

Sl.	Authority	Responsibilities	Communication Details
1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
5	Website/Portal (Helpdesk)	Queries regarding NDLI and its services	support@ndl.gov.in
6	Contents and Copyright Issues	Queries related to content curation and copyright issues	content@ndl.gov.in
7	National Digital Library of India Club (NDLI Club)	Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach	clubsupport@ndl.gov.in
8	Digital Preservation Centre (DPC)	Assistance with digitizing and archiving copyright-free printed books	dpc@ndl.gov.in
9	IDR Setup or Support	Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops	idr@ndl.gov.in