Near-infrared broadband emission from glass-clad Cr-doped yttrium orthosilicate crystal fiber

Cr 4+ :Y 2 SiO 5 crystal fiber was grown by the laser-heated pedestal growth method. Severe spinodal decomposition domains were observed at low growth speed. At a growth rate of 30 mm/min, the spinodal decomposition area ratio was reduced to 0.4%. Using borosilicate as the cladding, 0.85 mW of broadband emission with a 3-dB bandwidth of 246 nm centered at 1257 nm was generated. The near-infrared light source is eminently suitable for optical coherence tomography with reduced scattering for deep tissue penetration. The estimated axial resolution is 2.8 µm in free space.