Characterization and reducing method of optical feedback of DFB laser module in CATV systems

摘要

In this paper, the effects of a reflected laser beam on DFB laser intensity noise and nonlinear characteristics are investigated. It is shown that reflected power increases the intensity noise to 5 or more decibels over the intrinsic laser noise level. The undulation of light output versus current (L-I curves) result from the optical feedback is discussed. The nonlinearity impairments induced by moderate levels of optical feedback is not as severe as evaluated by static L-I curves. Some effective methods to reduce the optical reflection are put forward.