An all-optical upstream carrier generation scheme based on a Brillouin/erbium fiber laser (BEFL) is proposed for wavelength-independent optical network units in a wavelength-division multiplexed passive optical network. Experimental measurements show that the BEFL mainly operates in a single longitudinal mode and occasionally undergoes mode hopping given environmental fluctuations. Employing the proposed scheme, bidirectional transmission at 1.25-Gb/s over 20-km single-mode fiber is performed. Bit error rate measurement shows no crosstalk originating from Rayleigh backscattering and back-reflections in the network, due to a 0.08-nm-wavelength shift between the downstream and upstream carriers.
"All-optical upstream carrier generation scheme for optical network unit using a Brillouin/erbium fiber laser," Optical Engineering 48(6), 065001 (1 June 2009). https://doi.org/10.1117/1.3156050