1,720,967 research outputs found
Efficient superfluorescent emission at 974nm and 1040nm from a Yb-doped fibre
No full textEnd-pumping of an Yb-doped single-mode fiber has yielded > 10 mW and 30 mW of broadband superfluorescence at 974 nm and 1040 nm respectively. Slope efficiencies > 40% have been obtained. Pump wavelength dependent linewidths between 2 nm and 19 nm have been observed
Mode-locking of an Yb:Er fiber laser at 1.56µm
No full textWe describe the first operation of an actively mode-locked Er fiber laser at 1.56 µm. Short pulse laser sources operating in the 1.5 µm spectral range are needed for two reasons. First, current fiber optical communication systems operate in this spectral region because of the low loss of silica fibers. Second, 1.56 µm falls in the region of the negative group velocity dispersion (GVD) of silica. It is well known that by combining the effects of a Kerr nonlinearity to produce a frequency chirped pulse and negative GVD, significant pulse compression can be achieved. The laser we describe is of particular significance because it has all the ingredients needed to produce significant nonlinear propagation effects. In addition to operating at a suitable wavelength, the doped silica fiber already incorporates the Kerr nonlinearity and negative GVD. Thus, in contrast to other nonlinear laser systems which introduce an external cavity to produce the nonlinearity, in this laser the necessary nonlinear element is an integral part of the laser cavity. Currently the pulse peak powers in our laser are approaching the level at which nonlinear effects become significant
Efficient operation of an Yb sensitised Er fibre laser at 1.56µm
No full textWe report operation of a high-efficiency Yb:Er single-mode fibre laser. Pumping at wavelengths of 1064nm and at 820nm has shown low pump thresholds ( < 7 and 4mW) and high slope efficiencies (4.2 and 7.0%)
Measurements of fibre laser losses via relaxation oscillation
No full textWe describe a simple method for measuring fibre laser losses. The method is based on inducing relaxation oscillations by modulating the laser gain. From the oscillation frequency and known fibre parameters a loss figure can be extracted. Loss measurements performed on a Nd-doped fibre laser are presented
Active mode-locking of a Yb:Er fibre laser
No full textWe report FM mode-locked operation of a single-mode Yb:Er fibre laser at 1.56µm. To date pulses of 70ps duration and peak output powers of 90mW have been achieved
Efficient high-power continuous-wave operation of monomode Tm-doped fibre laser at 2µm pumped by Nd:YAG laser at 1.064µm
No full textDescribes the efficient 2 µm operation of a monomode Tm3+-doped silica-based fibre laser pumped with a Nd:YAG laser at 1.06 µm. The maximum fibre laser output power was 51 mW at 2.038 µm for an absorbed pump power of 230 mW. The threshold power was 60 mW absorbed and the slope efficiency with respect to absorbed power was 30%
Continuous-wave oscillation of a monomode ytterbium doped fibre laser
No full textThe last few years have seen intense interest and activity in the field of rare earth doped monomode fibre lasers and amplifiers [1,2],since these components could be used in fields as diverse as medicine and communications. Furthermore their small active volume offers a number of important advantages over conventional bulk glass lasers. We have chosen to investigate ytterbium doped fibre as it provides a very "clean" system (ie free from excited state absorption. Apart from the energy levels around 11,000cm-1 there are no other levels until the ultra-violet). The ytterbium fibre laser should therefore offer a good system on which to test some of the basic physics of fibre lasers. In addition it offers 3-level, 4-level and quasi 3-level laser transitions. Published work on ytterbium doped glass lasers in bulk form has been sparse with the main publication being that of Snitzer [3]. In this paper we describe the characteristics of an ytterbium-doped, silica based, monomode fibre laser operating at discrete wavelengths in the range 1035nm to 1076nm
Thulium-doped monomode silica fibre as a laser medium
No full textTm3+ is an interesting activator ion for a glass fiber laser because it emits in regions of the spectrum where such lasers have not previously operated. The fiber waveguide geometry confers a low threshold for laser action. Therefore, semiconductor diode laser pumping is a possibility since Tm3+ has an absorption band at ~800 nm
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