Design of all normal dispersion highly nonlinear photonic crystal fibers for supercontinuum light sources: Applications to optical coherence tomography systems

• Published in: Optics and laser technology Vol. 44; no. 4; pp. 976 - 980
• Main Authors: Hossain, M.A., Namihira, Y., Razzak, S.M.A., Islam, M.A., Liu, J., Kaijage, S.F., Hirako, Y.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-06-2012
• Subjects: Computer simulation; Dispersions; Finite element method; Finite element method (FEM); Light sources; Mathematical models; Nonlinearity; Optical Coherence Tomography; Optical coherence tomography (OCT); Optical pulses; Supercontinuum (SC); Finite element method (FEM); Optical coherence tomography (OCT); Supercontinuum (SC)
• ISSN: 0030-3992; 1879-2545
• DOI: 10.1016/j.optlastec.2011.10.021

In this paper, we investigate the generation of supercontinuum (SC) light source based on a highly nonlinear Germanium (Ge) doped photonic crystal fiber (HNL-GePCF) with all normal group velocity dispersion (GVD). By doping 3% higher refractive index Ge inside silica, nonlinear coefficient
γ
is increased as large as 110.6
W
−1
km
−1 at
1.31
μ
m
. Using finite element method (FEM) with a circular perfectly matched boundary layer (PML), it is shown through simulations that the proposed HNL-GePCF offers an efficient SC generation for dental optical coherence tomography (OCT) applications at
1.31
μ
m
. By propagating sech
2 picosecond optical pulses having 2.5
ps and 1.0
ps pulsewidth at a full width at half maximum (FWHM) through the proposed HNL-GePCF, output optical pulses are analyzed by the split-step Fourier method to obtain the spectral contents. Simulation results show that 105
m of the proposed HNL-GePCF can produce 100
nm spectrum (10
dB bandwidth) at
1.31
μ
m
for 2.5
ps input optical pulse and 110
m of such HNL-GePCF can produce 140
nm
spectrum (10
dB bandwidth) for 1.0
ps input optical pulse. Therefore, the highest longitudinal resolutions in the depth direction for dental OCT are found about
3.28
μ
m
for enamel and
3.51
μ
m
for dentin.