Control of waveguide properties by tuning femtosecond laser induced compositional changes

Abstract

Articles you may be interested in Optical characterization of femtosecond laser induced active channel waveguides in lithium fluoride crystals

Imaging Ellipsometry Determination of the Refractive Index Contrast and Dispersion of Channel Waveguides Inscribed by fs‐Laser Induced Ion‐Migration

“…Waveguide writing, optical and structural characterization details have already been described in detail in previous works . The waveguide inscription setup is based on a high repetition rate fs‐laser (Tangerine, Amplitude Systems, 500 kHz rep. rate) emitting ≈400 fs pulses at 1030 nm.…”

“…It is worth noting that fs‐laser induced local modification of the glass composition has been shown to provide an extremely efficient alternative for the production of high performance passive waveguides, waveguide optical amplifiers and lasers . We have shown that in several glass families including phosphates, tellurites, and borates, it is feasible producing high contrast waveguides by inducing the migration of an index carrier element (La, Te, …) toward the guiding region by fs‐laser irradiation at high repetition rate. The migration of the carrier index element occurs along with the cross migration of a fast diffusing element, normally an alkaline (Na, K).…”

“…The migration of the carrier index element occurs along with the cross migration of a fast diffusing element, normally an alkaline (Na, K). Although the mechanisms responsible for this process are not yet fully understood, the process has been shown to be highly controllable at least in the case of phosphate‐based glasses modified with La 2 O 3 and K 2 O. In fact, the local refractive index of the waveguides scales linearly with the local La content for relatively low concentrations .…”

“…Although the mechanisms responsible for this process are not yet fully understood, the process has been shown to be highly controllable at least in the case of phosphate‐based glasses modified with La 2 O 3 and K 2 O. In fact, the local refractive index of the waveguides scales linearly with the local La content for relatively low concentrations . However, although these later works suggest that the wavelength dependence of the refractive index contrast (Δ n ( λ )) of waveguides produced by fs‐laser assisted ion migration is small, there are no experimental measurements of the actual dispersion of Δ n ( λ ).…”

“…However, although these later works suggest that the wavelength dependence of the refractive index contrast (Δ n ( λ )) of waveguides produced by fs‐laser assisted ion migration is small, there are no experimental measurements of the actual dispersion of Δ n ( λ ). The index contrast of these waveguides has been measured by near‐field index profilometry at a single wavelength in the visible (670 nm), or estimated from NA measurements in the near IR (980 and 1620 nm). In this work, we have used imaging micro‐ellipsometry to measure, for the first time, the refractive index dispersion of waveguides produced in a La 2 O 3 modified, phosphate‐based glass by fs‐laser induced ion migration.…”