Polarization dependent intensity noise in Er/Yb co-doped fiber lasers

Abstract

Summary form only given. Co-doped fiber lasers have recently shown a wide range of novel capabilities from vector soliton formation to DBR cw lasing. Efficient energy transfer between the Yb and Er enables one to design a low-threshold, compact fiber laser. The dramatically reduced cavity length enables entirely new regimes of fiber laser operation. In fact, the ideal, quantum single-mode laser theory suggests that due to nonlinearities in the pump process, the low frequency intensity noise can potentially drop below shot noise under certain driving conditions. Our experiments on the low frequency intensity noise have revealed an anomalous polarization dependent resonance that may be evidence of coherent effects between Zeeman sublevels in the erbium lasing transition. The noise characteristics of an Er/Yb fiber laser have been studied and we report a novel polarization dependent resonance in the intensity noise.