A discretely tunable, single-frequency erbium-doped fiber ring laser demons
trates frequency locking to the 50-GHz ITU frequency grid with an accuracy
of +/-0.3 GHz and stability of +/-0.05 GHz over a 50-nm tuning range, An ou
tput power of 7 mW and an extinction ratio of 45 dB make this single-freque
ncy laser useful for a variety of DWDM applications.