A holey fiber based Brillouin laser

We demonstrate for the first time a Brillouin laser based on a Holey Fiber (HF). Using a simple Fabry-Perot resonator scheme containing a 75m long highly nonlinear HF with an effective area of 2.85µm2 we obtain a threshold of 125mW and a slope efficiency of ~70%

TeO2-ZnO-La2O3 glass composition for mid infrared wavelengths generation and transmission in optical fibers

Numerous applications in the Mid InfraRed (Mid IR) wavelength region still require basic optical components such as sources and optical fibers as transmission medium. Thanks to its mid IR transparency and nonlinearity, tellurite glass allows for developing both these types of components. However, practical applications require materials able to handle high optical intensity through enhanced material damage threshold. We report on the synthesis of a tellurite glass in the TeO2-ZnO-La2O3 (TZL) system which presents enhanced thermo mechanical properties with respect to typical tellurite glass compositions. We measured for the TZL composition a glass transition of 626 K, hence 70 K higher than the glass transition temperature of “standard” TZN compositions. The coefficient of thermal expansion was measured to be 138.10-6/K as compared to typical value of 180.10-6/K for TZN glass. We manufactured two types of fibers to assess the prospect for achieving high average power SC sources and Mid IR transmission in TZL glass fibers. First, a high Numerical Aperture (NA) aperture fiber was developed through standard rod in tube technique, where the cladding glass tube was manufactured by extrusion. The 50 μm core fiber presents an optical attenuation value of 0.26 dB/m at 1.55 μm. As an intermediate step towards the fabrication of an antiresonant hollow core fiber for high power transmission, we manufactured a preform and drew it into a cane. A TZL glass tube, 120 mm long and 9 mm/12 mm of inner/outer diameters (ID/OD) was manufactured via rotational casting technique. This latter tube was drawn into a tube of 2 mm in diameter which was cut into sections 130 mm long. Seven of those were stacked in another tellurite glass tube 6.5 mm/12 mm of ID/OD diameters, respectively. This preform was then drawn into a microstructured cane 1.6 mm in diameter which features tubular structures periodically arranged and of uniform thickness

Optimizing the curvature of elliptical cladding elements to reduce leakage loss in antiresonant hollow core fibres

We study systematically the effect of the curvature of glass membranes on the confinement loss of an antiresonant negative curvature hollow core fibre. Optimum curvatures are found that can reduce the fibre loss by orders of magnitude

Exploring the effect of the core boundary curvature in hollow antiresonant fibers

Through numerical simulations, we systematically study the leakage loss properties of a simplified novel hollow antiresonant fiber in which the core is surrounded by semi-elliptical elements. These studies lead to new insight into the effect of the curvature of the core boundary in antiresonant fibers. We observe in particular that in our design, there exists an optimum curvature of the elements—which we quantify simply through the aspect ratio of the ellipses—for which the fiber’s leakage loss is minimized. Furthermore, it is shown that elliptical elements can lead to orders of magnitude loss reduction as compared with similar fibers with circular ones

Double Pass Gain in Helium-Xenon Discharges in Hollow Optical Fibres at 3.5 μm

With recent advances in low-loss hollow core optical fibre technology [1], the concept of a flexible electrically pumped gas discharge laser has become a reality. Such a device would be capable of having a very narrow discharge tube, which has been shown to increase gain and output power in neutral noble gas lasers, while eliminating the need for long, rigorously straight glass tubes, a problem that has plagued past attempts to exploit this behaviour [2]. The narrow bore tubes have however made the discharge parameters harder to achieve, but recent work with DC-excited glow discharges provided the first indications of gain on the 3.11 μm, 3.37 μm and 3.51 μm Xenon transmission lines in fibres of over 1 m in length [3]. Here we continue with that work by carrying out a double pass experiment with these discharges, as a step towards a full laser cavity

Synchronously pumped mid-IR hollow core fiber gas laser

We report a synchronously pumped 3.16 μm acetylene fiber laser based entirely on low-loss silica hollow-core fiber. Our system oscillates at 2.568 MHz repetition rate, when pumped with a modulated amplified 1.53 μm diode laser.</p

Holey optical fibres for high nonlinearity devices

This thesis describes the development of a novel type of optical fibre, namely holey optical fibre (HF), for its specific incorporation in optical devices based on fibre nonlinearity. The development of the fabrication technique to produce such a fibre is discussed, and the fibres produced are characterized and used in device applications, proving the advantages of HF technology in the implementation of highly nonlinear optical devices, as well as showing its limitations. The initial fabrication problems that hindered the production of HFs with a high nonlinearity are identified and several strategies are adopted for its solution, including an experimental study of the HF drawing parameters, the invention of a novel holey fibre fabrication design based on an air clad HF jacket, the introduction of HF preform pressurization by means of a sealing technique and the use of a HF silica jacket. Thus long and robust HFs with a high nonlinearity can be reliably fabricated. In parallel with the development of the HF fabrication technique, the first applications of HF technology to high nonlinearity devices are investigated, ranging from a 2R data regenerator, based on only 3.3 m of a HF, to a Raman amplifier and a Brillouin laser based on long and robust HFs with low confinement losses, high birefringence and high anomalous dispersion at the operating wavelength. The negative impact of anomalous dispersion on the BER performances of a wavelength converter, and the limitations in terms of wavelength tuning range and phase matching of a high dispersion HF, directs our research towards the development of a HF with a relatively low normal dispersion (about -30 ps/nm . km) and an extremely high effective nonlinearity (gamma) = 70 W-1km-1). 15 meters of this HF were used to provide a demonstration of the first wavelength converter based on FWM, which allows error free-penalty free wavelength conversion of 10 Gbit/s data signals over a 10 nm bandwidth. As shown by these experiments one major issue of our HFs is the high polarization mode dispersion. We suggest a possible route to the solution of this problem, by systematically investigating the feasibility of a spun HF. We first use some hollow tubes to study the effects of preform spinning on the spin pitch, on a central hole and on an off-centre hole. Those preliminary results lead us towards the successful fabrication of the first spun HF, which demonstrates the applicability of the preform spinning technique to HF technology<br/