Title :
Spontaneous Rayleigh Seed for Stimulated Rayleigh Scattering in High Power Fiber Amplifiers
Author :
Smith, Arlee V. ; Smith, Jesse J.
Author_Institution :
AS-Photonics, Albuquerque, NM, USA
Abstract :
We estimate the Stokes wave starting power for stimulated thermal Rayleigh scattering (STRS) produced by thermal fluctuations in the fiber core that transiently alter the refractive index profile in the core. A transverse temperature gradient creates a transverse refractive index gradient via the thermooptic effect, and if the fluctuation frequency lies in the STRS gain band, it can couple light from mode LP01 to LP11 to seed STRS. This spontaneous Rayleigh seed may be stronger than the quantum background and may affect the mode instability thresholds of fiber amplifiers. This new seed estimate can be incorporated in STRS models to improve threshold calculations.
Keywords :
Rayleigh scattering; laser beams; laser modes; laser stability; optical fibre amplifiers; refractive index; stimulated scattering; thermo-optical effects; LP01 mode; LP11 mode; STRS gain band; Stokes wave starting power; fiber core; fluctuation frequency; high power fiber amplifiers; mode instability thresholds; quantum background; spontaneous Rayleigh seed; stimulated thermal Rayleigh scattering; thermal fluctuations; thermooptic effect; threshold calculations; transverse refractive index gradient; transverse temperature gradient; Noise; Optical refraction; Optical scattering; Optical variables control; Rayleigh scattering; Refractive index; Fiber lasers; fiber non-linear optics; laser amplifiers; modeling; scattering; theory;
Journal_Title :
Photonics Journal, IEEE
DOI :
10.1109/JPHOT.2013.2280526
