By removing the sericin from the silk fibers using Na

2

CO

3

solution

bio-fibers in diameters of 5~15 μm were fabricated and their morphology was observed using SEM and TEM. With the method of evanescent wave coupling

red/green/blue light at the wavelength of 671/532/473 nm was coupled into the micrometer-sized silk fiber-based optical fibers

followed by the investigation of the waveguiding properties and measurement of the optical propagating loss. Various photonic devices

including 2×2

3×1

1×4 and ring structures

were fabricated using the silk fibers. Experimental results confirm that the silk fiber-based bio-optical fibers exhibit good flexibility and surface smoothness. A propagating loss of 0.78 dB·mm

-1

was obtained for the green light at 532 nm guided in the silk fiber with diameter of 9.0 μm.