There is a need to develop a compact in dimension, high speed, bi-axial scanning, and robust scanner with Microelectromechanical Systems (MEMS) technology for in vivo imaging in Optical Coherence Tomography (OCT) applications. These MEMS based endoscoopes with distal beam scanning can image with higher speed, precision, and repeatability than conventional linear scanning endoscopes in which the entire endoscope is mechanically translated with respect to the observed tissue. Most importantly, with bi-axial scanning capability of the MEMS scanner, three dimensional in vivo real time...