2x2 photonic crystal fiber splitter for 800 nm spectral domain optical coherence tomography

Abstract

We report the fabrication and performance of the 2x2 photonic crystal fiber (PCF) splitter that was designed as a single mode splitter at the 800 nm optical band and used as the beam splitter for a spectral domain optical coherence tomography system. The PCF splitter has been made by coupling PCFs to a planar lightwave circuit (PLC) splitter chip. The PLC splitter chip was fabricated to have a single mode property at the 800 nm wavelength band and the PCFs were securely connected to the PLC chip through PCF block arrays having lithographically fabricated V grooves. The core size of the splitter chip was about 5 μmx5 μm and the core-cladding index difference was about 0.15 %. With the implemented PCF PLC splitter, we have obtained a low excess loss of 1.2 dB at 850 nm and a low polarization-dependent loss of 0.19 dB. With the proposed 2x2 PCF splitter, optical coherence tomography images of pearls were successfully obtained.