Journal of Photonics http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. A New Design for All-Normal Near Zero Dispersion Photonic Crystal Fiber with Selective Liquid Infiltration for Broadband Supercontinuum Generation at 1.55 μm Wed, 16 Apr 2014 12:47:53 +0000 http://www.hindawi.com/journals/jpho/2014/728592/ A new design of all-normal and near zero flattened dispersion based on all-silica photonic crystal fibers (PCFs) using selectively liquid infiltration technique has been proposed to realize smooth broadband supercontinuum generation (SCG). The investigation gives the details of the effect of different geometrical parameters along with the infiltrating liquids on the dispersion characteristics of the fiber. Numerical investigations establish a dispersion value of −0.48 ps/nm/km around the wavelength of 1.55 μm. The optimized design has been found to be suitable for SCG around the C band of wavelength with flat broadband wavelength band (375 nm bandwidth) and smooth spectrum with only a meter long of the PCF. The proposed structure also demonstrates good tunable properties that can help correct possible fabrication mismatch towards a better optimization design for various optical communication systems. Partha Sona Maji and Partha Roy Chaudhuri Copyright © 2014 Partha Sona Maji and Partha Roy Chaudhuri. All rights reserved. Simulation and Measurement of Solar Harvesting Enhancement of Silver Plasmonic Nanoparticles on GaSb Nanodots Mon, 24 Mar 2014 08:06:32 +0000 http://www.hindawi.com/journals/jpho/2014/327586/ The performance of a plasmonic antireflection layer which can be utilized for deep-space radiationresistant GaSb solar cells is investigated numerically and experimentally. The layer consists of nanodots made by plasma etching of a GaSb substrate and subsequent physical vapor deposition of Ag nanoparticles on the nanodot tips, in a partially ordered configuration determined by the plasma energy level. This technique is readily applicable to patterning of silicon. We measure the substrate reflectivity and model the reflection and absorption of the substrates using the 3D finite difference time domain (FDTD) method, which are realistically imported as 3D layers from the scanning electron microscopy (SEM) images. The variation of the height of the Ag nanoparticles on top of the GaSb pillars shows that the plasmonic effect remarkably enhances the absorption. The presence of GaSb pillars enhances absorption and tunes the maximum absorption wavelength peak. Lorenzo Rosa, Mukesh Ranjan, Mukul Bhatnagar, Daryoush Mortazavi, Subroto Mukherjee, and Saulius Juodkazis Copyright © 2014 Lorenzo Rosa et al. All rights reserved. Heat Conduction Modeling of Fiber Fuse in Single-Mode Optical Fibers Mon, 24 Feb 2014 09:16:31 +0000 http://www.hindawi.com/journals/jpho/2014/645207/ The unsteady-state thermal conduction process in single-mode optical fiber was studied theoretically with the explicit finite-difference method. We assumed that the vitreous silica optical fiber underwent pyrolysis at elevated temperatures to form (). We also proposed a model in which the optical absorption coefficient of the core layer increased with increasing molar concentration of . The core-center temperature changed suddenly and reached over  K when a 1.064-μm laser power of 2 W was input into a short core layer of 40 μm length, which was heated at 2923 K. This thermal wave, that is, a fiber fuse, increased in size and propagated toward the light source at a rate of about 0.54 m/s. The calculated propagation velocity of the fiber fuse was in agreement with the experimental value. Moreover, the average temperature of the radiated region of the core layer gradually approached a temperature of about 5700 K. It was found that the final average temperature was close to the experimentally reported values. Yoshito Shuto Copyright © 2014 Yoshito Shuto. All rights reserved. Bragg Gratings Induced in Birefringent Optical Fiber with an Elliptical Stress Cladding Wed, 11 Dec 2013 15:18:47 +0000 http://www.hindawi.com/journals/jpho/2013/936036/ The paper presents the results of writing of type I and high-performance type II fiber Bragg gratings in birefringent optical fiber with an elliptical stress cladding by a single 20 ns pulse of KrF excimer laser (248 nm). The gratings’ efficiency produced by a single pulse was up to 100%. Experimental results on visualization of these gratings are presented. I. K. Meshkovskiy, V. E. Strigalev, A. V. Kulikov, and S. V. Varzhel' Copyright © 2013 I. K. Meshkovskiy et al. All rights reserved. DQOBSR Protocol with QoS Provisioning for OBS Metro Rings Thu, 12 Sep 2013 10:04:12 +0000 http://www.hindawi.com/journals/jpho/2013/515074/ Optical burst switching (OBS) is the switching technology that enables optical internet with current technology. OBS networks are capable of operating with or without optical buffers and wavelength converters. Hence, medium access control (MAC) protocol plays an important role in resolving contention in such networks. Distributed Queue OBS Ring (DQOBSR) is one MAC protocol proposed for OBS ring networks. In this paper, the quality of service (QoS) provisioning scheme for DQOBSR protocol is presented. For the proposed protocol, service differentiation for different classes of traffic in terms of throughput and access delay is verified through simulation. A mathematical model is also presented for the computation of classwise mean access delay. The results obtained using the model are found to be in good agreement with the simulation results. M. Thachayani and R. Nakkeeran Copyright © 2013 M. Thachayani and R. Nakkeeran. All rights reserved. Monitoring of Moisture in Transformer Oil Using Optical Fiber as Sensor Wed, 24 Jul 2013 09:29:25 +0000 http://www.hindawi.com/journals/jpho/2013/528478/ This paper describes an optical fiber sensor and temperature sensor-based instrumentation system to measure the moisture content in transformer oil. The sensor system consists of (i) Diode Laser Source, (ii) a bare and bent multimode fiber as sensor probe, (iii) an LDR as detector, (iv) LM35-based temperature sensor, and (v) microcontroller system having a trained ANN for processing and calibration. The bare and bent optical fiber sensor and the temperature sensor LM35 are used to provide the measures of refractive index (RI) and temperature of a transformer oil sample. An ATmega32-microcontroller-based system with trained ANN algorithm has been developed to determine the moisture content of the transformer oil sample by sampling the readings of the bare bent optical fiber sensor and the temperature sensor. S. Laskar and S. Bordoloi Copyright © 2013 S. Laskar and S. Bordoloi. All rights reserved. Tunable Optical Filter Based on Mechanically Induced Cascaded Long Period Optical Fiber Grating Mon, 17 Jun 2013 17:38:40 +0000 http://www.hindawi.com/journals/jpho/2013/415059/ We have proposed and demonstrated experimentally a novel and simple tunable optical filter based on mechanically induced and cascaded long period optical fiber gratings. In this filter variable FWHM and center wavelength is provided by cascading long period and ultralong period optical fiber gratings with different periods in a novel fiber structure. We report here for the first time to our knowledge the characterization of mechanically induced long period fiber gratings with periods up to several millimeters in novel multimode-single-mode-multimode fiber structure. We have obtained maximum loss peak of around 20 dB. Sunita P. Ugale and Vivekanand Mishra Copyright © 2013 Sunita P. Ugale and Vivekanand Mishra. All rights reserved.