Simultaneous 6-Channel Optical Coherence Tomography Using A High-Power Telescope-Less Polygon-Based Swept Laser In Dual-Amplifier Configuration

Multichannel optical coherence tomography (MOCT) imaging is demonstrated using a high-power wavelength-swept laser source. The main benefit of MOCT is faster image acquisition rates without a corresponding increase in the laser tuning speed. The wavelength-swept laser was constructed using a compact telescope-less polygon-based filter in Littman arrangement. High output power, necessary for MOCT, was achieved by incorporating two serial semiconductor optical amplifiers in a ring laser cavity in Fourier domain mode-locked configuration. The laser has a measured wavelength tuning range of 111 nm centered at 1329 nm, coherence length of 5.5 mm, and total average output power of 131 mW at 43 kHz sweeping rate. Using this laser, a six-channel imaging system was constructed. The imaging arm consisted of a multi-fiber push-on connector mounted on a galvanometer-based scanner. All channels, spaced 250 mu m apart, were focused at the same depth. Six-channel OCT imaging to achieve 258 kHz scan rate is demonstrated. The increase in effective frame rate using multichannel acquisition may be beneficial for 3-dimensional in-vivo imaging where bulk tissue motion can adversely affect the image quality.