A NOVEL SWEPT LASER SOURCE BASED ON COMBINED TUNABLE FILTERS FOR OCT

A novel broad tunable bandwidth and narrow instantaneous line-width linear swept laser source using combined tunable filters working at 1,300 nm center wavelength is proposed. The combined filters consist of a fiber Fabry–Perot tunable filter and a tunable filter based on diffractive grating with scanning polygon mirror. In contrast to traditional method using single tunable filter, the trade-off between bandwidth and instantaneous line-width is alleviated. Parallel implementation of two semiconductor optical amplifiers with different wavelength range is adopted in the laser resonator for broadband light amplification. The Fourier domain mode locking swept laser source with combined tunable filters offers broadband tunable range with narrow instantaneous line-width, which is especially benefiting for high-quality optical frequency domain imaging. The proposed Fourier domain mode locking swept laser source provides a tuning range of 160 nm with instantaneous line-width of about 0.01 nm at sweeping rate of 15 kHz, a finesse of 16,000 is thus achieved.