Realization of single-mode telluride rib waveguides for mid-IR applications between 10 and 20 μm

Abstract

The feasibility of all-telluride integrated optics devices based on waveguides presenting a single-mode behavior in the spectral range (10-20 μm) is demonstrated. These waveguides are constituted of a several micrometer thick Te(82)Ge(18) film deposited onto a Te(75)Ge(15)Ga(10) bulk glass substrate by thermal coevaporation and further etched by reactive ion etching under the CHF(3)/O(2)/Ar atmosphere. The obtained structures were proven to behave as channel waveguides with a good single-mode transmission over the whole spectral range. These results allowed validating our technological solution for the fabrication of integrated optics modal filters for spatial interferometry.

Telluride buried channel waveguides operating from 6 to 20μm for photonic applications

“…Moreover this new component had a higher transmission than the previous ones. Indeed the overall transmission varied between 3.5% and 4.5% over the 10-20 lm range for the best previous components [10], whereas an average transmission of 6% was observed in the buried channel waveguides, with a value of 9% at k = 10 lm, as mentioned above.…”

“…Rib waveguides lie at the surface of the components and are not buried under a superstrate. We found that two rib waveguides were necessary to cover the whole 6-20 lm spectral range: a narrow rib waveguide, single-mode from 6 to 11 lm and a larger one being single-mode from 10 to 20 lm [10][11][12]. In the present paper, the design of a new alltelluride buried waveguide, able to cover the whole spectral range from 6 to 20 lm is presented.…”

“…The selected substrate was a Te 75 Ge 15 Ga 10 bulk glass [13,14] already proposed as substrate in previous rib waveguide devices [10][11][12]. The main motivations for this selection were a wide spectral transmission range, which covers the whole [6-20 lm] range, the absence of highly toxic or very volatile elements in the composition and the high thermal stability which allows fabricating large size (50 mm in diameter) homogeneous bulk glasses, in a reproductive way.…”

“…Due to the phenomenon of shadowing during the deposition of the superstrate, the sides of the core layer were not covered, leaving large voids. Reactive ion etching which was used for the fabrication of previous rib waveguides [10][11][12] had therefore to be discarded in favor of ion beam etching. The set-up used for the experiments was equipped with a system which allowed modifying the angle of the components during etching, making tailored sidewall profiles possible together with minimal sputtered re-deposition.…”

High-contrast GeTe4waveguides for mid-infrared biomedical sensing applications

“…A range of chalcogenide compositions have been explored for phase change memory devices [7] and crystalline GeTe 4 was reported to be a promising phase change memory material due to its good thermal stability and low power consumption [8]. Recently GeTe 4 rib waveguides were explored in the mid-IR range of 6-20 µm for spatial interferometry in the search for earthlike planets, where the index contrast between the GeTe 4 core and the Te 75 Ge 15 Ga 10 substrate was about 4 x 10 -2 [9][10][11]. In this paper, we describe the fabrication of a "high contrast" (Δn ≈ 1), GeTe 4 single mode rib waveguide on a ZnSe substrate, transmitting over the spectral range from 2μm -20µm.…”