Air-clad Photonic Crystal Fiber Research Articles

Thermal modeling of gain competition in Yb-doped large-mode-area photonic-crystal fiber amplifier.

We propose a new model for gain competition effects in high-power fiber amplifiers, which accounts for the thermal effects of heat load on the doped core overlap of the propagating light field. The full-vectorial nature of the fiber modes is modeled by an embedded finite-element method modal solver, and the temperature profile is calculated by a simple and efficient radial heat propagation solver. The model is applied to a Yb³⁺-doped LPF45 air-clad photonic-crystal fiber amplifier for coand counter-propagating pumping setups, showing gain competition in conditions of severe heat load.

Refractive Index Measurement of Liquids Based on Microstructured Optical Fibers

This review is focused on microstructured optical fiber sensors developed in recent years for liquid RI sensing. The review is divided into three parts: the first section introduces a general view of the most relevant refractometric sensors that have been reported over the last thirty years. Section 2 discusses several microstructured optical fiber designs, namely, suspended-core fiber, photonic crystal fiber, large-core air-clad photonic crystal fiber, and others. This part is also divided into two main groups: the interferometric-based and resonance-based configurations. The sensing methods rely either on full/selective filling of the microstructured fiber air holes with a liquid analyte or by simply immersing the sensing fiber into the liquid analyte. The sensitivities and resolutions are tabled at the end of this section followed by a brief discussion of the obtained results. The last section concludes with some remarks about the microstructured fiber-based configurations developed for RI sensing and their potential for future applications.

Phosphate Yb3+ photonic crystal fiber single-mode laser with enormous high pump absorption

We demonstrate a single-mode 6 cm long, phosphate fiber laser with maximum power of 9.0 W. Laser action output power per fiber length of 150 W m−1 was achieved and this is the highest value ever reported in a single-mode fiber laser using a phosphate glass fiber. The slope efficiency of the laser was 36.2% and lasing wavelength was 1028 nm. We used a 6% mol ytterbium-doped, air-clad photonic crystal fiber with the core of 30 µm in diameter. Estimated pump absorption in the fiber exceeded 400 dB m−1.

1.9 μm lasing with Tm3+ /Yb3+ co-doped air-clad fiber and 931 nm pumping

A 1.9 μm single mode laser is demonstrated by employing a newly developed large mode area Tm3+/Yb3+ co-doped air-clad photonic crystal fiber (PCF) in conjunction with 931 nm pumping for the first time. The PCF has an Yb3+ and Tm3+ ion concentrations of about 16 × 10−19 and 4 × 10−19 ions/cc, respectively. The laser produces a maximum output power of 4.6 mW with an efficiency slope of 0.70% at a multimode pump power of 2.3 W with a 2.7 m long PCF in a linear cavity with two fiber Bragg grating. The threshold of the input pump power is obtained at around 1.3 W. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1124–1126, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27523

Optical properties of all-solid microstructured optical fibers

In this Letter, we study optical properties of all-solid microstructured optical fiber made of soft glass. Such fibers have various interesting features including good geometrical stability, low fundamental transmission losses, high Kerr nonlinearity, and large solubility of rare-earth ions. By investigating transmission mechanism, mode structure, and numerical aperture of the fibers and confronting the results with theoretical calculations we demonstrate that the fibers have optical properties similar to those observed in air-silica microstructured optical fibers. This makes the all-solid soft-glass microstructured fibers very attractive for many potential applications. Full Text: PDF References J. R. Hayes, J. C. Flanagan, T. M. Monro, D. J. Richardson, P. Grunewald, and R. Allott, "Square core jecketed air-clad fiber", Optics Express, 14(22):10345-10350, 2006 CrossRef N. A. Issa, "High numerical aperture in multimode microstructured optical fibers", Applied Optics, 43(33):6191-6197, 2004 CrossRef M. Antkowiak, R. Kotynski, T. Nasilowski, P. Lesiak, J. Wojcik, W. Urbanczyk, F. Berghmans, and H. Thienpont, "Phase and group modal birefringence of triple-defect photonic crystal fibres", Journal of Optics A: Pure and Applied Optics, 7(12):763, 2005 CrossRef W. Reeves, J. Knight, P. St. Russell, and P. Roberts, "Demonstration of ultra-flattened dispersion in photonic crystal fibers", Optics Express, 10(14):609-613, 2002 CrossRef C. Martelli, J. Canning, B. Gibson, and S. Huntington, "Bend loss in structured optical fibres", Optics Express, 15(26):17639-17644, 2007 CrossRef T. A. Birks, J. C. Knight, and P. St. Russell, "Endlessly single-mode photonic crystal fiber", Optics Letters, 22(13):961-963, 1997 CrossRef L. Rindorf, J. B. Jensen, M. Dufva, L. H. Pedersen, P. E. Hoiby, and O. Bang, "Photonic crystal fiber long-period gratings for biochemical sensing", Optics Express, 14(18):8224-8231, 2006 CrossRef R. Buczynski, D. Pysz, I. Kujawa, J. Korzeniowski, T. Martynkien. F. Berghmans, H. Thienpont, and R. Stepien, "Supercontinuum generation with microstructured fibers made of soft glass", Photonics Letters of Poland, 1(3):109-111, 2009 CrossRef M. Nielsen, C. Jacobsen, N. Mortensen, J. Folkenberg, and H. Simonsen, "Low-loss photonic crystal fibers for transmission systems and their dispersion properties", Optics Express, 12(7):1372-1376, 2004 CrossRef W. Wadsworth, R. Percival, G. Bouwmans, J. Knight, and P. Russell, "High power air-clad photonic crystal fibre laser", Optics Express, 11(1):48-53, 2003 CrossRef X. Feng, T. M. Monro, P. Petropoulos, V. Finazzi. and D. Hewak, "Solid microstructured optical fiber", Optics Express, 11(18):2225-2230, 2003 CrossRef R. Buczynski, I. Kujawa, R. Kasztelanic, D. Pysz, K. Borzycki, F. Berghmans, H. Thienpond, and R. Stepien, "Supercontinuum generation in all-solid photonic crystal fiber with low index core", Laser Physics, 22(4):784-790, 2012 CrossRef M. Grabka, S. Pustelny, P. Mergo, and W. Gawlik, "Application of continuous wavelet transform for determination of fiber birefringence", Optics Express, 20(13):13878-13885, 2012 CrossRef M. Grabka, B. Wajnchold, S. Pustelny, W. Gawlik, K. Skorupski, and P. Mergo, "Experimental and theoretical study of light propagation in suspended-core optical fibre", Acta Physica Polonica A, 118(6):1127-1132, 2010 DirectLink M. J. F. Digonnet, Hyang Kyun Kim, G. S. Kino, and Shanhui Fan, "Understanding Air-Core Photonic-Bandgap Fibers: Analogy to Conventional Fibers", Journal of Lightwave Technology, 23(12):4169-4177, 2005 CrossRef H. Ebendorff-Heidepriem, R. G. Moore, T. M. Monro, "Progress in the fabrication of the next-generation soft glass microstructured optical fibers", AIP Conference Proceedings, 1055(1):95-98, 2008 CrossRef

Multimode interference in outer cladding large-core, air-clad photonic crystal fiber

It is described a large-core air-clad photonic crystal fiber-based sensing structure using the outer cladding as a light guide, which is highly sensitive to refractive index. The sensing head is based on multimodal interference, and relies on a single mode/large-core air-clad photonic crystal fiber/single mode fiber configuration. Using this configuration and controlling the light to travel in a segment of the outer cladding multimode fiber, it was possible to implement a sensing head and the results were obtained independently from variations of temperature, strain and refractive index. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1009–1011, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26726

Optical refractometer based on large-core air-clad photonic crystal fibers

A large-core air-clad photonic crystal fiber-based sensing structure is described, which is sensitive to refractive index. The sensing head is based on multimodal interference, and relies on a single-mode/large-core air-clad photonic crystal fiber (PCF)/single-mode fiber configuration. Using two distinct large-core air-clad PCF geometries-one for refractive index measurement and the other for temperature compensation, it was possible to implement a sensing head sensitive to refractive index changes in water as induced by temperature variations. The results indicated the high sensitivity of this sensing head to refractive index variations of water, and a resolution of 3.4×10(-5) refractive index units could be achieved.

Ytterbium doped phosphate glass photonic crystal fiber laser

AbstractWe demonstrate the 3% mol ytterbium doped phosphate glass air-clad photonic crystal fibre (PCF) laser of 43-cm length in single-mode operation. The fabrication and testing of the laser is introduced. The laser has the diameter of the core of 12 µm created in photonic microstructure and generates at wavelength of 1030 nm. Near 4-W output power and 14.6% slope efficiency against the launched pump power is demonstrated in preliminary characterization. The difference of refractive indices achieved in doped and undoped glass is Δn = 0.0004. We used the doped glass with the negative core-cladding Δn to assure the photonic crystal fibre way of single-mode propagation.

Application of an artificial neural network for simultaneous measurement of temperature and strain by using a photonic crystal fiber long-period grating

A general analysis of an inserted long-period grating in an air-clad photonic crystal fiber for temperature and strain measurement is presented. The temperature and strain can be detected simultaneously by using an artificial neural network. A simulation study was carried out with the data set generated by using theoretical strain and temperature sensitivities of the long-period gratings. It indicates that the maximum temperature error is 0.04 °C in the temperature range from 35 °C to 120 °C. At the same time, the maximum strain error is 2.7 µε in the strain range from 0 to 3000 µε.

Core temperature in super-Gaussian pumped air-clad photonic crystal fiber lasers compared with double-clad fiber lasers

In this paper we investigate the core temperature of air-clad photonic crystal fiber (PCF) lasers pumped by a super-Gaussian (SG) source of order four. The results are compared with conventional double-clad fiber (DCF) lasers pumped by the same super-Gaussian and by top-hat pump profiles.

Tunable, linearly polarized, intrinsically single-mode fiber laser using a 40-μm core-diameter Yb-doped photonic-crystal fiber

We report a 40-μm core-diameter, Yb-doped, air-clad photonic crystal fiber laser operating continuous-wave with intrinsic single-transverse-mode beam quality ( M 2 ∼ 1.25). The laser was tunable over the 1020–1050 nm range, exhibited a spectral linewidth ∼5 GHz, was temporally stable and linearly polarized with a polarization extinction ratio >93%. The maximum output power obtained was ∼14 W (limited by the available pump power).

Thermo-optical properties of air-clad photonic crystal fiber lasers in high power operation

We report on the investigation of the thermo-optical behavior of air-clad ytterbium-doped large-mode-area photonic crystal fiber lasers. Analytical and numerical models are applied to calculate the heat distribution and induced stresses in a microstructured fiber. The results are compared to conventional double-clad fiber lasers and design guidelines are provided to ensure maximum heat dissipation and scalability to power levels of several kWs.

High power air-clad photonic crystal fibre laser

An Ytterbium-doped photonic crystal fibre laser is demonstrated with a 100 microm2 core area and single transverse mode with an output efficiency of 30 %. Double-clad PCF laser structures are demonstrated with pump cladding NA greater than 0.8 and output power up to 3.9 W. Such lasers are potentially scalable to high power.