[1] Zubia J and Arrue J 2001 Opt. Fiber Technol. 7
101

[2] Koeppen C et al 1998 J. Opt. Soc. Am. B 15 717

[3] Bunge C A and Poisel H 2007 POF Modeling: Theory,
Measurement and Application (Herstellung und Verlag: Books on
Demand GmbH, Norderstedt)

[4] Ghatak A and Thyagarajan K 1998 Introduction to Fiber
Optics (Cambridge: Cambridge University Press) p 65

[5] Levfin V et al 1999 Proc. ICPOF p98

[6] Irie K, Uozu Y and Yoshimura T 2001 Proc. ICPOF p73

[7] Lee S et al 2003 Microwave Opt. Technol. Lett.
39 129

[8] Crank J 1975 The Mathematics of Diffusion (Oxford:
Clarendon)

[9] Djordjevich A and Savovic S 2005 Opt. Eng. 44
095003-1

[10] Sadiku M 1992 The Numerical Techniques in
Electromagnetic (Boca Raton, FL: CRC Press) p 141