Applications of ultralong Raman fibre lasers in photonics

This thesis presents a numerical and experimental investigation on applications of ultralong Raman fibre lasers in optical communications, supercontinuum generation and soliton transmission. The research work is divided in four main sections. The first involves the numerical investigation of URFL intra-cavity power and the relative intensity noise transfer evolution along the transmission span. The performance of the URFL is compared with amplification systems of similar complexity. In the case of intracavity power evolution, URFL is compared with a first order Raman amplification system. For the RIN transfer investigation, URFL is compared with a bi-directional dual wavelength pumping system. The RIN transfer function is investigated for several cavity design parameters such as span length, pump distribution and FBG reflectivity. The following section deals with experimental results of URFL cavities. The enhancement of the available spectral bandwidth in the C-band and its spectral flatness are investigated for single and multi-FBGs cavity system. Further work regarding extended URFL cavity in combination with Rayleigh scattering as random distributed feedback produced a laser cavity with dual wavelength outputs independent to each other. The last two sections relate to URFL application in supercontinuum (SC) generation and soliton transmission. URFL becomes an enhancement structure for SC generation. This thesis shows successful experimental results of SC generation using conventional single mode optical fibre and pumped with a continuous wave source. The last section is dedicated to soliton transmission and the study of soliton propagation dynamics. The experimental results of exact soliton transmission over multiple soliton periods using conventional single mode fibre are shown in this thesis. The effect of the input signal, pump distribution, span length and FBGs reflectivity on the soliton propagation dynamics is investigated experimentally and numerically

Applications of ultralong Raman fibre lasers in photonics

This thesis presents a numerical and experimental investigation on applications of ultralong Raman fibre lasers in optical communications, supercontinuum generation and soliton transmission. The research work is divided in four main sections. The first involves the numerical investigation of URFL intra-cavity power and the relative intensity noise transfer evolution along the transmission span. The performance of the URFL is compared with amplification systems of similar complexity. In the case of intracavity power evolution, URFL is compared with a first order Raman amplification system. For the RIN transfer investigation, URFL is compared with a bi-directional dual wavelength pumping system. The RIN transfer function is investigated for several cavity design parameters such as span length, pump distribution and FBG reflectivity. The following section deals with experimental results of URFL cavities. The enhancement of the available spectral bandwidth in the C-band and its spectral flatness are investigated for single and multi-FBGs cavity system. Further work regarding extended URFL cavity in combination with Rayleigh scattering as random distributed feedback produced a laser cavity with dual wavelength outputs independent to each other. The last two sections relate to URFL application in supercontinuum (SC) generation and soliton transmission. URFL becomes an enhancement structure for SC generation. This thesis shows successful experimental results of SC generation using conventional single mode optical fibre and pumped with a continuous wave source. The last section is dedicated to soliton transmission and the study of soliton propagation dynamics. The experimental results of exact soliton transmission over multiple soliton periods using conventional single mode fibre are shown in this thesis. The effect of the input signal, pump distribution, span length and FBGs reflectivity on the soliton propagation dynamics is investigated experimentally and numerically.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

RIN transfer in random distributed feedback fiber lasers

We numerically investigate relative intensity-noise transfer from a noisy pump to the generated Stokes component in random distributed feedback ultralong Raman fiber lasers. Results show transfer levels comparable to those in distributed Raman amplification and cavity-based ultralong Raman fiber lasers, but with some unique spectral features. © 2012 OSAThe authors wish to thank the financial support of Ministerio de Economía y competividad (MINECO) through grant TEC2011-27314.Peer Reviewe

RIN transfer in 2nd-order distributed amplification with ultralong fiber lasers

We investigate numerically the effect of ultralong Raman laser fiber amplifier design parameters, such as span length, pumping distribution and grating reflectivity, on the RIN transfer from the pump to the transmitted signal. Comparison is provided to the performance of traditional second-order Raman amplified schemes, showing a relative performance penalty for ultralong laser systems that gets smaller as span length increases. We show that careful choice of system parameters can be used to partially offset such penalty. © 2010 Optical Society of America.The authors wish to thank the financial support of Ministerio de Ciencia e Innovación (MICINN) through grant TEC2008-05791 and of Engineering and Physical Sciences Research Council (EPSRC) through grant EP/E015646/1.Peer Reviewe

Dual-wavelength, ultralong Raman laser with Rayleigh-scattering feedback

We present experimental demonstration of a 200-km-long, dual-wavelength Raman laser utilizing two slightly different-wavelength fiber Bragg gratings, one on each side of the fiber span. The obtained results clearly prove the generation of two independent Raman lasers with a distributed >random> Rayleigh scattering mirror forming a cavity together with each of the individual fiber Bragg grating reflectors. © 2010 Optical Society of America.Peer Reviewe

Brillouin optical time-domain analysis assisted by second-order Raman amplification

We propose and experimentally demonstrate a new method to extend the range of Brillouin optical time domain analysis (BOTDA) systems. It exploits the virtual transparency created by second-order Raman pumping in optical fibers. The idea is theoretically analyzed and experimentally demonstrated in a 50 km fiber. By working close to transparency, we also show that the measurement length of the BOTDA can be increased up to 100 km with 2 meter resolution. We envisage extensions of this technique to measurement lengths well beyond this value, as long as the issue of relative intensity noise (RIN) of the primary Raman pump can be avoided. © 2010 Optical Society of America.We acknowledge the support from the Spanish Ministry of Education and Science through projects TEC2008-05791, TEC2009-14423-C02-01 and TEC2009-14423-C02-02, the Ministerio de Fomento through project MIFFO (FOM-07/77) and the Comunidad de Madrid through project FACTOTEM2. Sonia Martin-Lopez acknowledges funding from the CSIC through the I3P post-doctoral program and the Ministerio de Ciencia y Tecnología through a “Juan de la Cierva” fellowship. The collaborative work was performed in the framework of the European COST Action 299 “FIDES”.Peer Reviewe

Development of IR frequency standards based on laser diodes | Desarrollo de patrones de frecuencia en el IR basados en láseres de diodo

Optical frequency combs have extremely high measurement accuracy for laser frequencies in the optics range, up to an order of approximately ~10-11. However, this technique requires narrow linewidth and frequency stable laser sources. The first set of measurement results we carried out were with an optical frequency comb in the 1550 nm range. These measurements are focused on the frequency stability, linewidth of the laser source and the absolute value of the optical frequency. Two wavemeters for optical communications were calibrated using the previous results. Furthermore, the stabilization of a laser diode in the Rb atomic absorption at 780 nm is presented. This source is expected to be used as calibration standard for wavemeters and as reference laser for optical clocks and frequency combs comparison. © 2012 Sociedad Española de Óptica.Este  trabajo  ha  sido  financiado  en  parte  por  el  Ministerio  de  Ciencia  e  Innovación  a  través  de  los  proyectos  TEC2009‐14423‐C02‐01  y  TEC2009‐14423‐C02‐02,  por  la  Comunidad  de  Madrid a través del proyecto FACTOTEM‐2 y por  Euramet  a  través  del  proyecto  JRP  IND14  FREQUENCHY.Peer Reviewe

Experimental study of the impact of pumping configuration in Raman-assisted fiber optic distributed Brillouin sensors

We have studied the effect of Raman amplification on the performance of a fiber optic distributed sensor based on Stimulated Brillouin scattering. A comparison between the results obtained without amplification and with three different Raman pumping configurations (co-propagating, counter-propagating and bi-directional) is presented.Peer reviewe

Procedimiento de deposición de capas delgadas de estequiometría controlada sobre sustratos mediante pulverización catódica reactiva a ángulo rasante

Procedimiento de deposición de capas delgadas de estequiometría controlada sobre sustratos mediante pulverización catódica reactiva a ángulo rasante. El objeto de la invención se refiere a un procedimiento para la deposición de capas finas sobre un sustrato, basada en la técnica de pulverización catódica reactiva, con el objetivo de controlar la composición química del material depositado y, en paralelo, aumentar la tasa de deposición respecto a la que se obtendría mediante este procedimiento en su modo convencional de uso. Se consigue evitar el envenenamiento del cátodo mediante la determinación del valor crítico de flujo de gas reactivo en el reactor a partir del cual se produce dicho fenómeno y disponiendo el sustrato en una configuración geométrica respecto del cátodo de forma que las especies pulverizadas de este lleguen a la superficie del sustrato según un ángulo rasante promedio, medido respecto de esta, con valores comprendidos entre 0º y 85º.Peer reviewedConsejo Superior de Investigaciones Científicas (España), Abengoa Research S.L.A2 Solicitud de patente sin informe sobre el estado de la técnic

The Development and Testing of a “Child-Proof” Advertising Disclosure to Disclose Embedded Advertising to Children

Procedimiento de deposición de capas delgadas de estequiometría controlada sobre sustratos mediante pulverización catódica reactiva a ángulo rasante. El objeto de la invención se refiere a un procedimiento para la deposición de capas finas sobre un sustrato, basada en la técnica de pulverización catódica reactiva, con el objetivo de controlar la composición química del material depositado y, en paralelo, aumentar la tasa de deposición respecto a la que se obtendría mediante este procedimiento en su modo convencional de uso. Se consigue evitar el envenenamiento del cátodo mediante la determinación del valor crítico de flujo de gas reactivo en el reactor a partir del cual se produce dicho fenómeno y disponiendo el sustrato en una configuración geométrica respecto del cátodo de forma que las especies pulverizadas de este lleguen a la superficie del sustrato según un ángulo rasante promedio, medido respecto de esta, con valores comprendidos entre 0º y 85º.Peer reviewedConsejo Superior de Investigaciones Científicas (España), Abengoa Research S.L.A2 Solicitud de patente sin informe sobre el estado de la técnic