A WIDELY TUNABLE NARROW-LINEWIDTH SEMICONDUCTOR FIBER RING LASER

We have demonstrated a novel approach to obtain a 0.1-nm line width la ser with 38-dB sidemode suppression by utilizing a 1.3-mu m semiconduc tor optical amplifier in a fiber unidirectional ring that consists of a linear polarizer and polarization controllers. The laser has a low-t hreshold current of 22.5 mA as well as a widely tuning range of 28 nm. The new approach is applicable to the 1.55-mu m region as well. It is expected that nanosecond wavelength tuning speed is feasible using th is approach in conjunction with fast electrooptic polarization control lers, short cavities and low-cavity losses.