New EDF design for high power and low nonlinearity applications

A new EDF with mode field diameter of 9 /spl mu/m and effective area of 65 /spl mu/m/sup 2/ at signal band 1550 nm is presented. Since large effective area suppresses the nonlinearities of the EDF, the output power limit of EDFA can be improved, and the splice loss is significantly reduced to less than 0.1 dB. This can be implemented by adding a side ring core to the conventional simple step core EDF; this additional core can control the spectral field profile of the EDF.