Low-loss chalcogenide waveguides for chemical sensing in the mid-infrared

Abstract

We report the characteristics of low-loss chalcogenide waveguides for sensing in the mid-infrared (MIR). The waveguides consisted of a Ge₁₁.₅As₂₄Se₆₄.₅ rib waveguide core with a 10nm fluoropolymer coating on a Ge₁₁.₅As₂₄S₆₄.₅ bottom cladding and were fabricated by thermal evaporation, photolithography and ICP plasma etching. Over most of the functional group band from 1500 to 4000 cm⁻¹ the losses were < 1 dB/cm with a minimum of 0.3 dB/cm at 2000 cm⁻¹. The basic capabilities of these waveguides for spectroscopy were demonstrated by measuring the absorption spectrum of soluble Prussian blue in Dimethyl Sulphoxide.

Small core Chalcogenide photonic crystal fiber for mid-infrared wavelength conversion: experiment and design

“…A good CE of -30 dB is obtained over 20 nm of total bandwidth. The dispersion estimated from the conversion bandwidth is D = -183 ps/(nm km), and compares well with the value D = -196 ps/(nm km) retrieved from COMSOL simulations, where we used the actual fiber geometry and Sellmeier equation for Ge 11.5 As 24 Se 64.5 [10]. Fig.2b shows CE values at different pump power levels for a 6 nm pump-signal detuning.…”

Mid-infrared integrated photonics on silicon: a perspective

“…The recently demonstrated suspended Ge membrane devices hold the potential to fully utilize the broad transparency band of Ge, although optical functions of these devices at >3-μm wavelength are yet to be realized [29,30]. Infrared-transparent chalcogenides and halides, on the other hand, can be monolithically deposited on Si or dielectric substrates via thermal evaporation or sputtering, with waveguides defined by using two compositions of different indices as core and cladding layers ( Figure 3K-L) [16,[31][32][33][34][35][36][37][38]. Compared to Si or Ge, the drawback of this approach is that chalcogenides and halides are generally not considered compatible with CMOS foundry processes.…”

Mid-infrared supercontinuum generation using dispersion-engineered Ge_115As_24Se_645 chalcogenide channel waveguide

“…A few of these ChG materials such as As 2 S 3 , As 2 Se 3 , Ge 11.5 As 24 S 64.5 and Ge 11.5 As 24 Se 64.5 glasses are highly suitable for making active and passive devices in the MIR region. Amongst them Ge 11.5 As 24 Se 64.5 glass has excellent film-forming properties with high thermal and optical stability under intense illumination [10]. Recently interest has grown in designing and optimizing planar waveguides made from Ge 11.5 As 24 Se 64.…”