Integrated optical system for spectral domain optical coherence tomography

An apparatus suitable for optical coherence tomography (OCT) scanning of a subject, the apparatus comprising:

• at least one source for providing a first signal and a reference signal;
• a photonics integrated circuit comprising:
• (i) a first path for receiving a reflected first signal, reflected from the subject;
• (ii) a second path for coupling the reflected first signal to the reference signal to provide an interference signal, and
• (iii) a variable delay for varying an optical path length of one of the reference signal and the first signal to match the optical path length of the reference signal to an optical path length of the reflected first signal, wherein the variable delay comprises a series of binary switches and a series of path elements of different lengths of L wherein the series of path elements comprises lengths of L up to 2N L, where N is a positive integer;
• and
• a detector for analyzing and detecting the interference signal.