A new broadband fiber light source for optical coherence tomography

Abstract

A new type of Gaussian-like broadband superfluorescent fiber light source suitable for optical coherence tomography (OCT) is introduced in this paper. Erbium-doped optical fiber simultaneously pumped by 980nm laser diode (LD) and 1480 nm LD is used as the gain medium. Both optical controllers and temperature controllers are employed to adjust the output of LDs and to improve the stability of output power of light source. A fiber coupler with a specific splitting ratio plus multi-stage long period fiber gratings are used to modulate the output spectrum so that the spectral profile of the broadband light source is near Gaussian. The output power is about 27mW with center wavelength at 1.57μm and the bandwidth over 75 nm. The experiment results reveal that the sidelobes of the autocorrelation function of the output spectrum are effectively suppressed, which can meet the need of optical coherence tomography.