Development Of All Fiber High Speed Time-domain Oct System

Optical Coherence Tomography which is based on the low coherence interference is a new medical imaging method. It can obtain the high resolution cross-section image of the interior biological tissue. With the advantages of high resolution, high sensitivity, non-radioactive, non-invasive, it has been widely applied in medical fields such as ophthalmology, dermatology, cardiology, dentistry and so on. So it has broad clinical and research prospects.Increasing the imaging speed can produce real time image of the biological tissue, reduce the life activities impact on the OCT system. In this thesis, based on the OCT principle and the previous OCT system of the laboratory, a new all fiber high speed time-domain OCT system is developed, which can acquire the image of biological tissue with high speed and accuracy.This thesis fulfills the work as follows:1,The optical structure of the all fiber high speed time-domain OCT system has been designed. The optical path matching and test of the fiber stretcher are completed.2,An in-line method based on the spectral interference pattern and nonlinear curve fit to measure the dispersion of the interferometer is put forward. According to the measured dispersion, a non-zero dispersion shifted fiber is used to compensate the dispersion of the interferometer.3,Based on the characteristic of the signal, the signal processing circuit has been developed, which includes the filter, logarithmic amplifier and amplifier.4,According to the synchronization theory of the system, the synchronization circuit based on the FPGA has been developed in order to synchronize the data acquisition, axial scan and lateral scan of the OCT system. The FPGA communicates with PC to facilitate the remote control of the system.5,The two-dimensional OCT images of the oral restoration, artificial caries, normal and caries extracted human teeth are obtained. The all fiber high-speed time-domain OCT system is compared with the previous system.