Improving the optical bandwidth of swept laser source using a dual-sinusoidal modulation of driving signal

The bandwidth of rapidly wavelength-swept laser sources used in optical coherence tomography is a crucial parameter determining axial resolution. A novel driving method of fiber Fabry-Perot tunable filter (FFP-TF) using a dual-sinusoidal signal is developed. This new method is illustrated in detail, and the bandwidth of the optical spectrum generated by the sinusoidal signal modulation and bandwidth compensation is quantified. The efficiency of the proposed method is demonstrated by comparison of a sinusoidal signal and a dual-sinusoidal signal in serial configuration with an FFP-TF in contrast to wavelength-swept laser source. An operation of a wavelength-swept laser source with a sweep rate of 20 kHz over a 132.9 nm range at a center wavelength of 1076 nm is demonstrated. The general features of dual-sinusoidal signal are discussed, which is important for the design of future broadband wavelength-swept laser sources. While conventional sinusoidal signal driving yields a limited output bandwidth, an increase in bandwidth may be achieved in wavelength-swept laser sources with a dual-sinusoidal signal.

Automated summary

This paper introduces a novel driving method of fiber Fabry-Perot tunable filter (FFP-TF) using a dual-sinusoidal signal, which can increase the bandwidth of wavelength-swept laser sources and improve the axial resolution.