Szukana fraza: [Abstrakt = "We demonstrate a stable and tunable single\-longitudinal\-mode SOA\-EDF ring laser for high\-speed data transmission systems. The laser is constructed by incorporating an SOA into the EDF ring cavity. The SOA acts as a saturable absorption high\-pass filter to suppress cavity mode partition noise at low frequencies. Such design ensures a stable and single\-frequency operation for more than several hours. The ring laser has a 30 nm tuning range in the C band and a 0.8 nm wavelength spacing to match 100\-GHz ITU\-T grids. The variation in the maximum power is smaller than 0.02 dB and the optical signal\-to\-noise ratio is above 53 dB. By employing this fiber laser, a 10 Gbps non\-return zero data transmission over a 50 km long single\-mode fiber with a power penalty less than 2.4 dB is demonstrated."]