High numerical aperture square lattice structure photonic crystal fiber for optical coherence tomography

In optical coherence tomography (OCT) system, high numerical aperture (NA) PCF is required for collecting back scattering light for detailed information from body tissue. In this paper, we propose a new structure of high NA zero dispersion single mode photonic crystal fiber (PCF) for OCT at 0.83 μm, 1.06 μm and 1.31 μm wavelengths which are used for ophthalmology, dermatology and dentistry, respectively. The properties of the proposed PCF are simulated by using finite difference method (FDM) with an anisotropic perfectly matched boundary layer. The PCF offers not only high NA but also both zero dispersion and single mode operation at each center wavelengths. Simulation results show that the designed PCF at target wavelengths improves the transverse resolution of OCT systems.