Fabrication of photonic devices directly written within glass using a femtosecond laser

1. Microscope image of a 2-µm period (a) line and (b) dot patterns directly written inside fused silica with 320 nJ pulse energy Optical memory Optical micrograph of waveguides written inside fused silica glass using a 300-500 nJ, 1 kHz, and 100 fs pulse train focused with a 0.42 NA microscope objective Microscope image of U-groove machined by femtosecond laser pulses; (a) top view (×500), (b) side view (×500). Fiber aligned one-input and two-output channels of U-grooved optical splitter Schematic diagram of U-grooved optical splitter. Line width and dot diameter are 0.5 µm a b a b Optical microscope image of 3-D dot patterns consisted of three layers, which is applicable to optical memory Far-field pattern of the optical splitter’s output with a 1550 nm laser beam coupled into the input waveguide a b c (a) I, (b) C, and (c) U, respectively. The layer gap and dot pitch are 7 µm and 2 µm, respectively. The splitting ratio is approximately 1:1 Fabrication of photonic devices directly written within glass using a femtosecond laser Ik-Bu Sohn, Man-Seop Lee; Information and Communication University119, Munjiro, Yuseong-gu, Daejeon, 305-714, Korea