Simulating and Designing Brillouin Gain Spectrum in Single-Mode Fibers

Koyamada, Yahei; Sato, Shunsuke; Nakamura, Shigeo; Sotobayashi, Hideyuki; Chujo, Wataru

doi:10.1109/jlt.2003.822007

Cited by 193 publications

(68 citation statements)

References 13 publications

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“…For 10% Ge-doped silica if the acoustic wave damping time is considered as T B = 6.469 ns [29], then we have, v B = 49.205 MHz. For such a structure, often it is assumed that v B to be equal for all acoustic modes and is assumed to be around MHz for all silica based fibers [27].…”

Section: Resultsmentioning

confidence: 99%

Characterization of acousto-optical interaction in planar silica optical waveguide by the finite element method

Rahman

2016

J. Opt. Soc. Am. B

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This is the accepted version of the paper.This version of the publication may differ from the final published version. A full-vectorial finite element based approach is used to find accurate modal solutions for the acoustic modes in a Ge-doped planar silica optical waveguide. To enhance the accuracy of the solution, the existing structural symmetry is exploited and rigorous analyses of the interactions between the guided acoustic and optical modes are performed. The Stimulated Brillouin Scattering (SBS) frequency and the overlaps between the fundamental and the higher order transverse and longitudinal acoustic modes and the fundamental quasi-TE optical mode are presented. Permanent

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Section: Resultsmentioning

confidence: 99%

Characterization of acousto-optical interaction in planar silica optical waveguide by the finite element method

Rahman

2016

J. Opt. Soc. Am. B

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“…These can reach 100 K or more. Another possibility is to use a transversally varying speed for the acoustic wave involved in the Brillouin interaction, e.g., with varying germanium and aluminum concentrations across the core [7], [8], [9], [10]. This way, it is possible to independently control propagation of the acoustic and optical waves, and an acoustic speed variation as large as 9% has been achieved [10].…”

Section: Single-frequency Fiber Mopas and Synthetic-aperture Lasersmentioning

confidence: 99%

Fiber MOPAs with high control and high power

Nilsson

Yoo

Dupriez

et al. 2008

Asia Optical Fiber Communication and Optoelectronic Exposition and Conference

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High power fiber sources have reached several kilowatts of output power, and are now leading contenders for many applications. Important attractions include control, efficiency, manufacturability, and reliability. We will exemplify opportunities and limitations for these revolutionary sources. IntroductionHigh power fiber sources are now leading contenders for many important applications requiring powers from a few watts up to several kilowatts. Beyond raw power, fibers offer advantages such as control, efficiency, manufacturability, and reliability. These derive from the fundamental fiber geometry, as well as advances in fiber design, fabrication, and pump diodes, largely driven by the optical communications industry. Master oscillator -power amplifier (MOPA) configurations build on the unique combination of high power, high efficiency, high gain, and broad gain bandwidth of rare-earth (RE) doped fibers. In MOPAs, the output from highly controlled, low power seed lasers can be amplified to ultrahigh power levels whilst preserving the desired seed characteristics. High control is much simpler at low powers. For example, high-speed lithium niobate modulators can be used to control the amplitude as well as the phase of the seed light. This makes MOPAs revolutionary light sources that can enable and dominate a range of devices and application areas. At the same time, the fiber MOPAs are being pushed ever closer to their physical limits. Here, we will exemplify both opportunities and limits of high-power fiber MOPAs. Fiber Raman amplifier with controllable gain spectrum Raman amplifiers offer the potential to generate gain at any arbitrary wavelength over several Stokes orders with an appropriate pump source. This has proved a very effective and successful way of providing gain at wavelengths not directly available with RE-doped fibers. Most of this success has been achieved using CW pump diodes, but in recent years there has been renewed interest in pulsed pumping of Raman amplifiers. This has been mainly in the telecommunications area through time-division multiplexed pumping schemes [1], but also in other areas due to advances in diode-seeded high power fiber MOPA systems [2]. A MOPA allows for excellent control of the pulse parameters which is not easily available from Q-switched or mode-locked lasers. This opens up new opportunities for controlling the Raman gain spectrum through control of the pulse parameters. We have experimentally investigated this, by pumping a fiber Raman amplifier with step-shaped optical pulses delivered from an ytterbium (Yb) doped fiber MOPA [3], [4]. With the instantaneous power of each step appropriately tailored, different parts of the pulse transfer their energy to different Stokes orders, leading to a controllable gain spectrum covering multiple Stokes orders. This opens up opportunities for an ultra-broadband Raman amplifier with near-instantaneous electronic control of the gain spectrum.

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“…Several approaches have been exploited for the computation of the BGS starting from the modal properties of the fiber [2,3]. The usual assumption is that the fiber can support a single optical mode so that only a limited set of axially-symmetric acoustic modes are evaluated.…”

Section: Introductionmentioning

confidence: 99%

Full modal analysis of the Brillouin gain spectrum of an optical fiber

Tartara

Codemard

Maran

et al. 2009

Optics Communications

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We present a numerical study of stimulated Brillouin scattering in optical fibers based on a full modal analysis of the acoustic and optical properties. The computation of each acoustic mode supported by the fiber structure allows us a deep and detailed investigation of the characteristics of the Brillouin gain spectrum. We focus our attention on optical fibers acting as acoustic antiwaveguides where the biggest contribution to the Brillouin response often comes from very high-order modes but it is sometimes overlooked because of computational issues. Our analysis clearly highlights their role and their dependence on the physical and geometrical structure of the fiber. INTRODUCTIONFiber lasers are nowadays emerging as the most powerful solid-state laser technology because of their compactness, their reliable and efficient operation, and the high power levels attainable. However several issues degrading the laser performance arise and need to be tackled when increasing the light intensity in the fiber. Stimulated Brillouin scattering (SBS) is often the most detrimental effect for narrow-line lasers [1]. Moreover SBS sets a limit to the power which can be transmitted in a fiber communication system. On the other hand SBS can be conveniently employed for sensing applications and for all-optical signal elaboration. A great deal of research has thus been devoted to the design of fiber geometries in terms of their Brillouin response. The Brillouin gain spectrum (BGS) summarizes all the main properties characterizing a fiber from this point of view and hence is usually the object of the numerical investigations of SBS.Several approaches have been exploited for the computation of the BGS starting from the modal properties of the fiber [2,3]. The usual assumption is that the fiber can support a single optical mode so that only a limited set of axially-symmetric acoustic modes are evaluated. In this paper we present a numerical study of SBS in optical fibers based on a full modal analysis of the acoustic behaviour. The computation of the characteristics of each acoustic mode supported by the fiber structure allows a deep and detailed investigation of the BGS. This is particularly important in the case of optical fibers acting as acoustic antiwaveguides as higher-order modes often provide the biggest contribution to the Brillouin response.

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Simulating and Designing Brillouin Gain Spectrum in Single-Mode Fibers

Cited by 193 publications

References 13 publications

Characterization of acousto-optical interaction in planar silica optical waveguide by the finite element method

Characterization of acousto-optical interaction in planar silica optical waveguide by the finite element method

Fiber MOPAs with high control and high power

Full modal analysis of the Brillouin gain spectrum of an optical fiber

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