Direct UV written integrated planar waveguides using a 213 nm laser

Abstract

We present the first demonstration of integrated waveguides in planar silica devices fabricated using direct UV writing with 213 nm laser light. Waveguides were produced with different writing fluences and the NA and MFD of each were measured. Single mode waveguides were achieved at fluence values one tenth that typically required when operating with a 244 nm laser, allowing for more rapid fabrication. A maximum in-plane index change of 2.4 x10 −3 for a writing fluence of 5 kJ cm −2 was estimated from NA measurements. Finally cutback measurements were performed and a propagation loss of 0.42 ± 0.07 dB cm −1 was directly measured, though losses as low as 0.2 ± 0.03 dB cm −1 are indicated through calculations.

4-by-4 Integrated Waveguide Coupler Based on Bi-Directional Propagation in Two Single-Mode Waveguides

“…However, realistic losses of e.g. 0.2 dB/cm in silica waveguides [23], [24] will not qualitatively change the results and conclusions derived below. Note that the waveguides are generally birefringent and we only consider vertically polarized (y-polarized) modes.…”

“…Here we target in particular linear operations on a small number of fiber-coupled narrow bandwidth light pulses, e.g, for applications in optically connected quantum networks [21]. Direct UVwritten waveguides in a planar silica platform provide an ideal implementation of such devices since they allow for fiber coupling with small insertion loss of 0.1 dB [22] and low propagation losses of 0.2 dB/cm [23], [24]. With direct UV-writing technology it is also possible to simultaneously inscribe waveguides and Bragg gratings [25].…”

Direct 213 nm UV written Bragg gratings and waveguides in planar silica without hydrogen loading

“…Compared with a typical argonion laser this source can be compact and cost-effective in terms of footprint and power consumption. In the past this new laser source has been used to produce strong Bragg gratings within the core of hydrogen-free SMF-28 fibre using a phase mask technique [2] and single-mode waveguides in hydrogen-loaded planar silica [3]. Here we report the first successful fabrication of integrated waveguides and Bragg gratings by 213 nm direct UV writing in both hydrogen loaded and hydrogen-free planar silica samples.…”

213 nm laser written waveguides in Ge-doped planar silica without hydrogen loading

“…In one experiment a total of fifteen straight waveguides were UV written along a planar doped silica-on-silicon chip of 15 mm length. Writing fluences ranged from 5 to 75 kJ cm −2 , which are an order of magnitude larger than for hydrogen loaded 213 nm written waveguides [32]. This resulted in stage translation speeds from 1.9 to 0.12 mm min −1 , giving a total time of approximately 14 hours to write all fifteen waveguides.…”

“…Similar doped silica-on-silicon samples to those reported in [32] were used in this study. These were fabricated through flame hydrolysis depostition (FHD).…”