The traditional single reference arm swept-source optical coherence tomography (SSOCT) has the ability to image 7mm axial length, however larger depth can not be obtained directly. Conventionally, the extending depth can be obtained via special system design or multi-arm imaging. However, in this paper we design a SSOCT system with large detection depth which only need one reference arm. The difference between this system and the traditional is that the proposed system use a high-speed scanning laser. The large imaging depth range is achieved owing to the increased k-trigger number and the related sample point number in one A-scan period. The sample signal and the reference signal interfere in the optical fiber coupler, and then it is detected by a balanced detector. The digital signal of each A-line goes through spectrum shaping, background removal, mirror image removal, dispersion matching and the Fourier transform, then the A-scan signal can be obtained. 512 A-scan signal comprise the B-scan frame. The imaging depth can reach 54mm, and the axial imaging resolution is 7.5 μm . The frame rate is 5fps of the SSOCT system which can be improved if algorithm is simplified further. The system can be employed in human eye axial-length measurement and dimensional measurement.
|