LAUSR

Abstract A few mode wavelength division multiplexing coupler (WDMC) based on a five-core fiber is proposed to couple pump light with the wavelength of 980 nm into few-mode fiber amplifiers supporting four LP modes at 1550 nm. The WDMC is composed of a few-mode core and four single mode cores surrounding it. The pump light is coupled into LP 01 , LP 11 , LP 21 , LP 02 mode, respectively. Numerical simulation results show that the coupling efficiency for pump light is 99.6%, 99.3%, 99.9%, and 99.9%, and the power loss of the signal light in the LP 01 , LP 11 , LP 21 , and LP 02 modes in few mode core is 0 , 0 . 01 , 0 . 03 , 0 . 10 , and 0 . 18 dB , respectively. The proposed few-mode WDMC with lower insertion loss and easier fabrication, which can provide four LP modes of pump light in the few mode fiber, is an ideal candidate for pump scheme for the few-mode fiber amplifier.