Chromium doped zinc selenide optical fiber lasers

Abstract

The optical fiber geometry is known for rugged, high power laser sources that are preferred for many applications, but is typically limited to the visible and near-infrared regions of the electromagnetic spectrum due to the transmission limits of silica (< 2 µm). This wavelength range could be extended into the mid-infrared using transition metal doped, crystalline II-VI optical gain media, but these materials cannot be fabricated into optical fibers using conventional glass drawing methods. An in-situ high pressure chemical vapor deposition method for the fabrication of silica-cladded ZnSe fiber cores uniformly doped with Cr 2 + is reported. Optical pumping experiments reveal that these doped fibers exhibit threshold behavior and thus function as mid-infrared optical fiber lasers. Finite element calculations show that undesirable thermal effects common in bulk II-VI crystals are mitigated in the fiber geometry.

Semiconductor core fibres: materials science in a bottle

“…Zinc Selenide core fibres 128 , and Cr-doped ZnSe 129 as well as an array of Ge/ZnSe core fibres have been fabricated by HPCVD 130 . Reactive formation in polymer hosts has also been reported 131 .…”

Recent progress of semiconductor optoelectronic fibers

“…Diffusion doping is a common strategy to incorporate transition metal ions in bulk ZnSe, however the uniform concentration region can be produced is about 1 mm and the process is not compatible for fabricating fibers. Considering the volatility and stability in high temperature and pressure (the condition for HPCVD) of various organometallic molecules, it was determined that metallocene bis(cyclopentadienyl)chromium(II) (Cp 2 Cr) and n-butylferrocene are the suitable precursors for Cr and Fe dopant in the HPCVD ZnSe fabrication [79,88]. The mode profile at 1.55 µm of Cr 2+ :ZnSe is shown in Fig.…”

“…The first demonstration was a pulsed Cr 2+ :ZnSe fiber laser pumped at a wavelength of 2.09 µm that exhibited lasing at 2.3 µm with a threshold about 800 µJ (Fig. 6(a)) [79]. A second demonstration was a continuous wave laser based on a Fe 2+ doped ZnSe fiber pumped at 2.94 µm, see Fig.…”

“…Fig.6(a) Spectral emission of Cr 2+ :ZnSe fiber laser above and below the laser threshold. Reprinted with permission from Ref [79]…”

Glass: The carrier of light—Part II—A brief look into the future of optical fiber

“…While progress has been made toward lower losses, longer lengths, expanded ranges of materials, and cladded fibers, the nature of the crystal growth process is necessarily slow, limiting the utility and practicality of such optical fibers. However, they are of great future interest, particularly for fiber lasers operating at wavelengths not accessible with dopants in glasses, for example, 215,216 and enhanced fiber nonlinear optics 217 . A game changer for nonlinear fiber optics would be the development of suitably low loss and dispersion tailored acentric crystalline phases possessing a nonzero χ (2) nonlinearity, enabling a wide range of electro‐optic and wave‐mixing effects 218,219 …”