Determination of dispersion induced relative intensity noise through spectral linewidth measurements

With the recent advent of erbium-doped fiber amplifiers, CATV networks are now utilizing 1550 nm technologies to achieve high fidelity transmission over long fiber links. Although the lower fiber attenuation at 1550 nm serves to improve the network´s power budget, the non-zero dispersion frequently necessitates the use of external modulation to avoid dispersion induced distortions. Fiber dispersion, when combined with certain laser characteristics, can also lead to excess link noise. In this paper, we discuss the specific source laser characteristics which determine this excess noise as well as how they can be accurately measured.