Improving broadband emission within Bi/Er doped silicate fibres with Yb co-doping

Abstract

We present Bi/Er/Yb co-doped silicate fibre (BEYDF) which is fabricated by co-doping with Yb2O3 into Bi/Er doped silicate fibre (BEDF), and investigate its properties associated with Yb co-doping. Spectral absorption, emission, emission lifetime, ESA and gain characteristics of BEYDF are experimentally investigated and compared with those of BEDF to reveal particular impacts of Yb on the broadband spectral characteristics. We measured Yb3+ emissions at 980 nm and 1040 nm in BEYDF, and emissions related to Bi active centres (BACs, at 1100 nm and 1420 nm) and Er3+ (1530 nm) in BEYDF and BEDF under 830 nm pumping. Evidences of Yb3+→BAC energy transfer process, in addition to the normal Yb3+→Er3+ energy transfer process are noticed. Compared with BEDF, BEYDF has shown both broadened and enhanced emissions and gain. In particular, the overall emission bandwidth within a 4 dB intensity is attained over Δλ = (1000−1590) nm in BEYDF, and just over Δλ = (1250−1590) nm in BEDF. The overall emission intensity is enhanced by a factor of 2.5 in BEYDF over that of BEDF. Furthermore, Er3+ gain at 1530 nm is increased and BAC linked ESA at 1400 nm is reduced in BEYDF. Yb3+ related emissions and energy transfers from the excited Yb3+ to both the Er3+ and BACs can explain the improvements of emission and gain. These results indicate that Yb3+ co-doping can be used to expand and enhance broadband emissions and gain in BEYDFs.