Modeling of Cascade Lasing in Dy : Chalcogenide Glass Fiber Laser With Efficient Output at 4.5 $\mu$m

Modelling of a simple Dy3+ doped chalcogenide glass fibre laser for mid-infrared light generation

“…A similar performance, but using standard double-clad fibres, has been predicted by Quimby et al (2008) based on Dy 3+ doped chalcogenide glasses, to give a 3 level cascade lasing system: 6 H 11/2 , 6 H 13/2 and 6 H 15/2 (Fig. 1).…”

“…The more simple design relies only on the feedback provided by Fresnel reflection at chalcogenide glass-air interfaces, thereby reducing the technological challenge of realising the design. We demonstrate that the efficiency of this simple laser design can be increased to match that of the more complicated design proposed by Quimby et al (2008) by terminating one fibre end with a mirror (Fig. 2c).…”

“…A large pumping efficiency (∼20%) was anticipated, and a 1 dB/m fibre loss assumed, to give a potentially large continuous tuning range of fibre lasers, when operating in the vicinity of the 4.5 µm output wavelength. Although the results presented (Quimby et al 2008) clearly demonstrated that a double-clad fibre cascade system may be used for efficient generation of MIR light, the suggested laser structure is still quite challenging in terms of practical realisation requiring the fabrication of two pairs of wavelength-matched fibre gratings in the Dy 3+ -doped chalcogenide glass fibre. Furthermore, the Dy 3+ -doped chalcogenide glass fibre simulated as a laser had a large dopant ion concentration (7 × 10 19 ions cm −3 ).…”

“…2b), which although still based on the 3 level cascade lasing system suggested by Quimby et al (2008), is more simple because it avoids the use of gratings. The more simple design relies only on the feedback provided by Fresnel reflection at chalcogenide glass-air interfaces, thereby reducing the technological challenge of realising the design.…”

“…Such analysis will allow identification of the optimal parameters for fibre laser structures to be realised which are technologically less challenging than that of (Quimby et al 2008), while still achieving output power levels of 100 mW or above at ∼4.5 µm wavelength. This paper comprises four sections: below in Sect.…”