Download presentation
Presentation is loading. Please wait.
1
Rare-Earth-Doped Fiber Lasers
Anneke Batenburg
2
Introduction Fiber Lasers : lasers having a doped fiber as gain medium or (sometimes) just lasers where most of the laser cavity consists of fibers. Dopants usually are rare-earth ions, like erbium, neodymium, ytterbium... Hier kan ook het plaatje uit het boek komen.
3
Erbium Energy Levels Transition between 4f-levels: actually forbidden (parity), but can occur through interaction with lattice electrons. 4f electrons are very well shielded from crystal: little collisional decay and long u. Transition at 1.53 μm: very useful for telecom Inhomogeneous broadening in glass. De I-I overgang is eigenlijk verboden, omdat er geen verandering in pariteit optreedt, maar bestuderen
4
Pumping Scheme Possible pumping wavelengths: 0.98 and 1.48 μm. Usually pumped with laser diodes.
5
Parameters...
6
Advantages of Fibers Large surface-to active-volume ratio → good heat dissipation, less thermal effects Low losses in the fiber, permits construction of very long lasers and amplifiers, leading to very high single-pass gain and low pump treshold values Broad gain bandwidth (glass) Easily integrable in communication systems, compactness, stability
7
Output Fluctuations Spiking is common in three-level solid-state laser systems, and also in erbium-doped fiber lasers. Spiking can be suppressed by choosing suitable pumping wavelength (Loh et al) 980 nm 1510 nm
8
Double-Clad Fibers Ordinary single-mode fibers have to be pumped by single-mode diode lasers, typically limited in power (~W). Solution: double-clad fibers. Laser light propagates in core, pump light in highly multimode inner cladding. Allows for higher power laser diode pumping (and higher gain)
9
Photonic Crystal Fibers
Nonlinear effects restrict ultimate power of fiber lasers. Desired: single mode fibers with large mode area (low power density) The renaissance and bright future of fibre lasers, Tünnermann et al.
10
Photonic Crystal Fibers 2
More missing air holes lead to larger mode-areas (but take care of bending losses).
11
Double-Clad PCF (Makes in-coupling of pump light easier by larger numerical apertures) 80 W output power, could be scaled up to 260 W, authors expect 4 kW in the future
12
Questions? www.erbium.nl/nanophotonics www.rp-photonics.com
Laser Funadementals Optical Fiber Sensors: Principles and Components, edited by John Dakin and Brian Culshaw,Artech House The renaissance and bright future of fibre lasers, A Tünnermann, T.Schreiber, F. Röser, A. Liem, S. Höfer, H. Zellmer, S. Nolte and J. Limpert, Journal of Physics B Suppression of self-pulsing behaviour in erbium-doped fiber lasers with resonant pumping: experimental results, W.H. Loh and J.P. de Sandro, Optics Letters 1996
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.