Supercontinuum Generation in a Silicon Nanowire Embedded Photonic Crystal Fiber for Optical Coherence Tomography Applications

In this paper, we design a silicon nanowire embedded photonic crystal fiber (SN-PCF) using fully vectorial finite element method. Further, we analyze the various optical properties, namely, waveguide dispersion and nonlinearity by varying the core diameter from 400 to 500 nm for a wide range of wavelengths from 0.8 to 1.7 mu m. The proposed structure exhibits a low second (-0.4909 ps(2)/m) and third order (0.6595 10(-3) ps(3)/m) dispersions with very high nonlinearity (1358 W(-1)m(-1)) for 480 nm core diameter at 0.8 mu m wavelength. Besides, we investigate the evolution of supercontinuum at 0.8, 1.3 and 1.55 mu m wavelengths for an incredibly low input pulse energy of 2.5 pJ. The numerical results corroborate that the proposed SN-PCF provides a wider supercontinuum bandwidth of 1250 nm at 0.8 mu m, 1100 nm at 1.3 pm and 800 nm at 1.55 mu m wavelengths. We demonstrate longitudinal resolution of 0.16 mu m at 0.8 mu m wavelength for oph-thalmology and dermatology, 0.41 mu m at 1.3 mu m wavelength for dental imaging and 0.8 mu m at 1.55 mu m wavelength also for dental imaging. To our knowledge, these are the highest resolution ever achieved in biological tissue at 0.8, 1.3 and 1.55 mu m wavelengths.