Parallel drawing of multiple bent optical waveguides using a spatial light modulator

Multiple optical waveguides inside glass were drawn in parallel using multiple light spots, which were formed by focusing a spatially phase-modulated femtosecond laser pulse. Because the spatial phase distribution was modulated by a computer-generated hologram (CGH) on a liquid-crystal spatial light modulator (SLM), bent structures were formed in the drawn waveguides by changing the positions of the light spots by switching the CGHs when the waveguides were being drawn. We confirmed that a He–Ne laser beam can be guided through the fabricated waveguides, and we found that the propagation loss of the waveguides was determined by both the steps for changing the beam position and the number of times the CGHs were switched. We also explain the method we used to reduce the time required to calculate the CGHs used to create bent waveguides