J4 ›› 2012, Vol. 29 ›› Issue (3): 303-310.

• Laser Tech. and Devices • Previous Articles     Next Articles

Transverse mode competition and signal to noise ratio in few-mode fiber amplifiers

LIU Qing, WEI An-kun, ZHENG Rui, WANG An-ting, XU Li-xin, MING Hai   

  1. Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei 230026, China
  • Received:2011-04-28 Revised:2011-05-06 Published:2012-05-28 Online:2012-05-22

Abstract:

Transverse mode distribution and dopant profile are introduced in propagation-rate equations. An approximate numerical algorithm by multilayer method is presented to calculate the power of amplified signal and ASE in multimode fiber amplifiers. Numerical results of the propagation-rate equations before and after the improvement are compared. It shows that power filling factor is the key indication to describe the transverse mode competition behavior. Dopant profile makes great effect in mode selection and 60%-70% confinement of flat doping is more helpful in high-order mode suppression. ASE significantly dropped and SNR increased when the ions are doped more concentrated in the fiber core.

Key words: laser physics, transverse mode competition, multilayer method, amplified spontaneous emission, filling factor

CLC Number: