R.C. Moore

Bismuth glass holey fibers with high nonlinearity.

We report on the progress of bismuth oxide glass holey fibers for nonlinear device applications. The use of micron-scale core diameters has resulted in a very high nonlinearity of 1100 W-1 km-1 at 1550 nm. The nonlinear performance of the fibers is evaluated in terms of a newly introduced figure-of-merit for nonlinear device applications. Anomalous dispersion at 1550 nm has been predicted and experimentally confirmed by soliton self-frequency shifting. In addition, we demonstrate the fusion-splicing of a bismuth holey fiber to silica fibers, which has resulted in reduced coupling loss and robust single mode guiding at 1550 nm.

Highly nonlinear and anomalously dispersive lead silicate glass holey fibers

In this paper we present significant progress on the fabrication of small-core lead-silicate holey fibers. The glass used in this work is SF57, a commercially available, highly nonlinear Schott glass. We report the fabrication of small core SF57 fibers with a loss as low as 2.6 dB/m at 1550 nm, and the fabrication of fibers with a nonlinear coefficient as high as 640 W-1km-1. We demonstrate the generation of Raman solitons at ~1550 nm in a short length of such a fiber which highlights the fact that the group velocity dispersion can be anomalous at these wavelengths despite the large normal material dispersion of the glass around 1550nm.

High-nonlinearity dispersion-shifted lead-silicate holey fibers for efficient 1-/spl mu/m pumped supercontinuum generation

This paper reports on the recent progress in the design and fabrication of high-nonlinearity lead-silicate holey fibers (HFs). First, the fabrication of a fiber designed to offer close to the maximum possible nonlinearity per unit length in this glass type is described. A value of /spl gamma/=1860 W/sup -1//spl middot/km/sup -1/ at a wavelength of 1.55 /spl mu/m is achieved, which is believed to be a record for any fiber at this wavelength. Second, the design and fabrication of a fiber with a slightly reduced nonlinearity but with dispersion-shifted characteristics tailored to enhance broadband supercontinuum (SC) generation when pumped at a wavelength of 1.06 /spl mu/m-a wavelength readily generated using Yb-doped fiber lasers-are described. SC generation spanning more than 1000 nm is observed for modest pulse energies of /spl sim/ 100 pJ using a short length of this fiber. Finally, the results of numerical simulations of the SC process in the proposed fibers are presented, which are in good agreement with the experimental observations and highlight the importance of accurate control of the zero-dispersion wavelength (ZDW) when optimizing such fibers for SC performance.

Exposed-core microstructured optical fibers for real-time fluorescence sensing

New methods for fabricating glass exposed-core microstructured optical fiber are demonstrated. The fiber designs consist of an optical fiber with a suspended micron-scale core that is partially exposed to the external environment, which is particularly useful for sensing. These fibers allow for strong evanescent field interactions with the surrounding media due to the small core size, while also providing the potential for real-time and distributed measurements. The experimental performance of an exposed-core fiber is compared to an equivalent microstructured fiber with an enclosed (protected) core in terms of their performance as evanescent field sensors. We demonstrate that the exposed-core fiber can provide a significantly improved measurement response time.

Towards efficient and broadband four-wave-mixing using short-length dispersion tailored lead silicate holey fibers

We demonstrate four-wave-mixing based wavelength conversion at 1.55 mum in a 2.2 m-long dispersion-shifted lead-silicate holey fiber. For a pump peak power of ~6 W, a conversion efficiency of -6 dB is achieved over a 3-dB bandwidth of ~30 nm. Numerical simulations are used to predict the performance of the fiber for different experimental conditions and to address the potential of dispersion-tailored lead silicate holey fibers in wavelength conversion applications utilizing four-wave-mixing. It is shown that highly efficient and broadband wavelength conversion, covering the entire C-band, can be achieved for such fibers at reasonable optical pump powers and for fiber lengths as short as ~2 m.

Fluoride glass microstructured optical fiber with large mode area and mid-infrared transmission

We demonstrate an extruded fluorozirconate microstructured fibre with large mode area, loss of 3 dB/m at 4 mum and negligible excess loss relative to a corresponding unstructured fibre.

Halide-modified Ga–La sulfide glasses with improved fiber-drawing and optical properties for Pr3+-doped fiber amplifiers at 1.3 μm

We report Cs halide-modified Ga-La sulfide glasses, a new class of chalcohalide glasses with improved fiber-drawing and optical properties suitable for Pr3+-doped fiber amplifiers at 1.3µm. Cs halide-modified Ga-La sulfide glasses retain the essential characteristics of low phonon-energy and good rare-earth solubility of pure Ga-La sulfide glasses. However, they transmit further into the UV/visible region of the spectrum, and can meet the need of high thermal stability for fiber fabrication

High nonlinearity extruded single-mode holey optical fibers

We report the fabrication of the first microstructured single-mode non-silica glass fiber from an extruded preform. The measured effective nonlinearity (/spl gamma/) is 550 W/sup -1/ km/sup -1/, more than 500 times larger than standard silica fiber.

Soliton-self-frequency-shift effects and pulse compression in an anomalously dispersive high nonlinearity lead silicate holey fiber

We report the fabrication of a single-mode lead silicate glass holey fiber with anomalous dispersion and a record nonlinearity of /spl gamma/=640 W/sup -1/km/sup -1/ at 1550nm. We report what we believe to be the first soliton and pulse compression experiments in this new class of fibers.

Advances in microstructured fiber technology

We review our recent progress in the area of microstructured fiber design, fabrication and applications with particular emphasis on the control of both the nonlinearity and dispersion.