Parallel Drawing of Multiple Bent Optical Waveguides Using a Spatial Light Modulator

Abstract

Multiple optical waveguides inside glass were drawn in parallel using multiple light spots, which were formed by focusing a spatially phasemodulated 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. #

Ultrafast-laser-inscribed 3D integrated photonics: challenges and emerging applications

“…Using a computer-generated hologram, multiple foci can be positioned in three dimensions [92,93]. This enables the single-sweep writing of several waveguides [94][95][96][97] or the inscription of multiscan waveguides in a single pass [98].…”

Progress in ultrafast laser processing and future prospects

“…Spatial manipulation of laser pulses is effective to increase the fabrication speed, that is, increased throughput by multibeam parallel processing and enhancement of the laser energy utilization efficiency [135][136][137][138][139][140]. Temporal beam shaping enables the laser energy to be efficiently deposited to the materials, which improves the fabrication quality and resolution.…”

“…Multiple optical waveguides have been simultaneously written in glass by direct writing using multiple laser spots generated with an SLM [136]. Different types of bent optical waveguides can be written by continuously changing the positions of the laser spots through the switching of computer-generated holograms (CGHs) because the spatial phase distribution is modulated by the CGH on a liquid-crystal SLM, which is not possible with passive optical components.…”

Holographic vector-wave femtosecond laser processing for fabrication of orientation-controlled nanostructures

“…It was called holographic femtosecond laser processing [2,3], and has the advantages of high-throughput pulsed irradiation and high energy-use efficiency of the pulse. The holographic femtosecond laser processing has been widely used in many applications, for example, optical waveguide fabrication [4], fabrication of volume phase gratings in polymers [5], surface structuring of silicon [6], twophoton polymerization [7], two-photon microscopy [8] and optical tweezers [9]. These applications have been mainly performed based on a holographic control of spatial phase of the light.…”