[OPTICAL REVIEW Vol. 19, No. 5 (2012) 315-319]
© 2012 The Japan Society of Applied Physics

Supercontinuum Generation at 1.55 μm Using Highly Nonlinear Photonic Crystal Fiber for Telecommunication and Medical Applications

Md. Anwar HOSSAIN1*, Yoshinori NAMIHIRA1, and S. M. Abdur RAZZAK2

1Graduate School of Engineering and Science, University of the Ryukyus, Nishihara, Okinawa 903-0213, Japan
2Department of EEE, Rajshahi University of Engineering and Technology, Rajshahi-6204, Bangladesh

(Received October 28, 2011; Accepted July 10, 2012)

In this paper, we present a theoretical calculation of a highly nonlinear germanium (Ge) doped photonic crystal fiber with all-normal group velocity dispersion to design a supercontinuum (SC) light source at 1.55 μm. By doping 3% higher refractive index Ge inside the host silica, the nonlinear coefficient is increased to a value as large as 60.5 W-1 km-1 at 1.55 μm. A 10 dB bandwidth of a 120 nm SC spectrum for a 2.5 ps input optical pulse and a 10 dB bandwidth of a 190 nm SC spectrum for a 1.0 ps input optical pulse have been found using the same fiber length of 200 m and input optical power of 18 W. The coherent lengths of the generated SC light sources are found to be 8.8 μm for a 2.5 ps input optical pulse and 5.6 μm for a 1.0 ps input optical pulse. Therefore, the highest longitudinal resolution at 1.55 μm is found to be about 4.0 μm for biological tissues.

Key words: optical coherence tomography (OCT), supercontinuum (SC), photonic crystal fiber (PCF), group velocity dispersion (GVD), nonlinear fiber optics, chromatic dispersion (D), finite element method (FEM)

*E-mail address: namihira@eee.u-ryukyu.ac.jp