InN-Based Optical Waveguides Developed by RF Sputtering for All-Optical Applications at 1.55 <inline-formula> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula>

Abstract

Abstract-We report on the design, fabrication and optical characterization of InN-based optical waveguides aiming at their application as all-optical limiters at 1.55 µm. The InN guiding layers are grown by radio-frequency (RF) sputtering on sapphire substrates. Experimental cut-back method and nonlinear optical transmittance measurements were performed for the developed devices. The waveguides present nonlinear behavior associated with two photon absorption process. A nonlinear absorption coefficient ranging from ~43 cm/GW to ~114 cm/GW is estimated from optical measurements. These results open the possibility of using RF sputtering as a low cost and thermally harmless technique for the development and overgrowth of InN-based optical waveguides in future III-nitride all-optical integrated circuits working at telecom wavelengths.

III‐nitride‐based waveguides for ultrafast all‐optical signal processing at 1.55 μm

“…InN WGs were defined by UV lithography and etched down by RF sputtering at ∼7 nm min −1 , following the conditions described in Ref. . The WG facets were mechanically polished.…”

“…In this work, we report the fabrication of three different WG architectures based on III‐nitrides on sapphire platform for application in all‐optical integrated circuits at 1.55 µm: (i) GaN WGs incorporating GaN/AlN QDs to operate as ultrafast saturable absorbers (ii) nanocrystalline InN WGs grown by RF sputtering to operate as low‐cost ultrafast reverse saturable absorbers , and (iii) passive AlN WGs deposited by RF sputtering to act as low‐cost passive interconnectors.…”