Time-Domain Optical Coherence Tomography System With Balanced Detection

As optical coherence tomography (OCT) plays an important role in biomedical research and clinical applications, an1310nm time-domain optical coherence tomography system is developed. The system includes a double-pass Fourier-domain rapid scanning optical delay line in the reference arm and features balanced detection. Firstly, the double-pass Fourier-domain rapid scanning optical delay line, and its operation are detailed. Then the theory of balanced detection is derived and the mathematical expression of interference signal is obtained. Next, the design of balanced detection circuit, the data acquisition software based on LabVIEW and four envelope demodulation methods are introduced, and the signal to noise ratio is analysed in detail in order to optimize OCT system. Finally, some important parameters, such as line scan rate, axial resolution, and sensitivity, are measured. Moreover, a sample is scanned to test the function of this system. This thesis will be helpful for building a practical OCT system.