1.3 m broadband swept sources with enhanced nonlinear effects

In this work, a new structure is used to enhance the nonlinear effect in the cavity, which improves the performance of the 1.3[Formula: see text][Formula: see text]m broadband swept source. The swept source adopts a semiconductor optical amplifier (SOA), a circulator, a coupler, and a tunable filter. In the structure, the light passes through the nonlinear medium (SOA) twice in two opposite directions, which excites the nonlinear effect and increases the performance of the swept source. The tunable filter is based on a polygon rotating mirror and gratings. Traditionally, multiple SOAs are adopted to improve the sweep range and the optical power, which increases the cost and complexity of the swept source. The method proposed in this paper can improve the spectral range and optical power of the swept sources without additional accessories. For the short-cavity swept source, the power increases from 6[Formula: see text]mW to 7.7[Formula: see text]mW, and the sweep range increases from 98[Formula: see text]nm to 120[Formula: see text]nm. The broadband swept sources could have wide applications in biomedical imaging, sensor system, measurement and so on.