Optical Design of a Vertically Integrated Array-type Mirau-based OCT system

SPIE Photonics Europe 2014. Bruxelles (Belgique), du 14/04/2014 au 17/04/2014Skin cancer is the most diagnosed type of cancer. While an early treatment usually offers good therapy prospects, effective diagnosis techniques are required. Today traditional biopsy is still the reference diagnostic technique, which has the drawback of a long diagnosis time and invasiveness. In recent years, new optical system based on optical coherence tomography were developed for early diagnostics of skin cancer. But as these systems are still bulky and expensive, they're still available at specialized hospitals only. Therefore we present the optical design of a Vertically Integrated Array-type Mirau-based OCT System (VIAMOS), which will allow non-invasive 3D optical biopsies of skin for early diagnostics of skin cancer. The VIAMOS system constitutes a miniature, low cost, full-field optical coherence tomography system combining swept-source OCT, phase-shifting interferometry and MOEMS technologies. It will provide 3D tomograms of human skin from a measurement volume of 8 x 8 x 0.5 mm³ with an axial and transverse resolution of about 6 µm. The swept-source will be realized as a miniaturized, MEMS-based wavelength-tuning Fabry-Perot Interferometer and a near-infrared superluminescent diode resulting in a linewidth of approximately 1 nm and a scanning range of 50 nm. The wafer stacked measurement device consists of 4 x 4 Mirau-Interferometer channels with movable reference mirrors to realize heterodyne detection and will be fabricated by means of MOEMS technologies. The signal detection will be realized using a fast new developed smart camera chip, which features 4 x 4 multiple regions of interest and on-chip signal processing. In this contribution, we present the optical design of the sensor and provide results of an extensive stray light analysis of the system