L. Dong et al., OPTICAL FIBERS WITH DEPRESSED CLADDINGS FOR SUPPRESSION OF COUPLING INTO CLADDING MODES IN FIBER BRAGG GRATINGS, IEEE photonics technology letters, 9(1), 1997, pp. 64-66
A new method for suppression of coupling from guided optical modes int
o cladding modes in an optical fiber Bragg grating using a fiber with
a strongly depressed cladding is proposed, Strong suppression of the c
oupling has been demonstrated both theoretically and experimentally.