Toward Miniaturized Optical Coherence Tomography

Optical coherence tomography (OCT) is a widely used optical imaging technology with an increasing number of applications [1]. It has particular importance in the medical field since it can provide non-invasive, sub-micrometer resolution diagnostic images. Current OCT systems contain fiber-based or free-space bulky components which make these instruments costly. A significant decrease in the size and cost of an OCT system is possible through integrated optics. With a suitable material technology and optimum design, one can fabricate extremely compact and low-cost OCT systems, especially suited for applications in which instrument size may play an important role. In the literature there is only limited data on the implementation of OCT systems on a chip [2-3]. In this work, we present the successful attempt toward miniaturization of a spectral-domain OCT (SD-OCT) system by designing an arrayed waveguide grating (AWG) spectrometer in silicon-oxynitride (SiON) for the 1300-nm spectral range. The AWG spectrometer, with its excellent performance and compactness, has a high potential for various spectroscopic applications. The operation principle of an AWG is explained in detail in Ref. [4].