Femtosecond Laser-inscribed Non-volatile Integrated Optical Switch in Fused Silica based on Microfluidics-controlled Total Internal Reflection

Compact packaged silicon photonic Bragg grating sensor based on a ball lens interface

“…This is an established technique which has previously been applied e.g. for the fabrication of optofluidics [15], optical switches [16], V-grooves for fiber alignment [17], and optical resonators [18]. For the current work, the FLICE technology was further optimized specifically for achieving a conical holder with a 45°slope angle.…”

Femtosecond laser written Bragg grating sensors with passive fiber alignment structures in fused silica

“…Regular waveguides are formed by using a pulse energy of 300 nJ, a pulse repetition rate of 500 kHz and a translation speed of 0.5 mm/s [4]. In the case of Bragg grating waveguides, the same pulse energy and pulse repetition rate are used, with an external modulation of 500 Hz with a duty cycle of 60 %.…”

Laser Written Glass Interposer for Fiber Coupling to Silicon Photonic Integrated Circuits

“…To allow for low-loss optical coupling between the optical fiber and the laser written waveguide, the end-face of the V-groove is written along the direction perpendicular to the femtosecond laser polarisation, which allows for the lowest facet roughness. As the laser polarisation is kept fixed during the process, the waveguides are written along the direction parallel to the laser polarisation, which leads to the lowest waveguide propagation loss [15]. In a second step, the fused silica substrate is submerged into an aqueous KOH solution so that the V-grooves are etched.…”

“…Single mode optical waveguides are written with a stage translation speed of 0.5 mm/s, and a laser power of 125 mW, resulting in a mode field diameter matching to single mode fiber and an acceptable waveguide propagation loss [15]. The waveguides are defined 43 µm below the surface, matched to the V-groove design as described in the next section.…”

“…This allows recording the waveguide mode field diameter and as such estimating the minimum achievable coupling loss. The waveguide propagation loss on the other hand, was obtained using Optical Frequency Domain Reflectometry (LUNA OVA 5000) [16], according to the procedure detailed in [15]. To allow for a reliable waveguide loss measurement, a 10 cm long waveguide sample was prepared, using the laser settings as detailed in section 2.2.…”