Self-Seeded RSOA Fiber Cavity Laser and the Role of Rayleigh Backscattering—An Analytical Model

Reflective semiconductor optical amplifiers (RSOAs) in a fiber cavity are attractive self-seeding optical sources for wavelength division multiplexed (WDM) access networks. This paper presents an analytical model of this fiber cavity laser (FCL). The model accounts for the Rayleigh backscattering (RB) of the fiber cavity as a primary mechanism of optical feedback inside the FCL. Moreover, it also includes the reflectivity of the remote node mirror. The purpose of the model is to analytically estimate the threshold RSOA gain required for the FCL to lase, by taking into account the fiber cavity length, the related attenuation and the RB. The model is suitable to experimentally characterize the Rayleigh backscattering coefficient, once the threshold gain of RSOA-FCL is measured.