850 nm centered wavelength-swept laser based on a wavelength selection galvo filter

A wavelength-swept laser is constructed using a free space external cavity configuration coupled with a fiberbased ring cavity at the 850 nm region. The external cavity filter employs a galvo-mirror scanner with a diffraction grating for wavelength selection. The filter is connected to a ring cavity through an optical circulator.The ring cavity contains a broadband semiconductor optical amplifier with a high optical output. The performance of this laser is demonstrated with broad bandwidths and narrow linewidths. The 3 dB linewidth and the bandwidth of this source are 0.05 nm（;0 GHz） and 48 nm, respectively. The maximum output power is 26 m W at 160 m A current.