Amorphous silicon nanowires combining high nonlinearity, FOM and optical stability

Abstract

Abstract:We demonstrate optically stable amorphous silicon nanowires with both high nonlinear figure of merit (FOM) of ~5 and high nonlinearity Re(γ) = 1200W −1 m −1 . We observe no degradation in these parameters over the entire course of our experiments including systematic study under operation at 2 W coupled peak power (i.e. ~2GW/cm 2 ) over timescales of at least an hour.

New CMOS-compatible platforms based on silicon nitride and Hydex for nonlinear optics

“…Although initial measurements yielded a FOM no better than c-Si (~0.5) [120,121], more recent results have shown FOMs ranging from 1 [122] to as high as 2 [123,124], allowing very high parametric gain (+26dB) over the C-band [125]. While a key problem for this material has been a lack of stability [126], very recently a-Si nanowires were demonstrated [127] that displayed a combination of high FOM of 5, high n 2 (3-4 times that of crystalline silicon) and good material stability at telecom wavelengths. A key goal of all optical chips is to reduce both device footprint and operating power.…”

“…Nonlinear parameters for CMOS compatible optical platforms a-Si [127] c-Si [2,47] SiN [55][56][57] Hydex [63,76] [55,56]. The nanowire dimensions are 500nm thick by 1 µm wide.…”

Nonlinear Group IV photonics based on silicon and germanium: from near-infrared to mid-infrared

“…We did not include specific data in Figure 3 for amorphous silicon, since different groups reported highly variable n 2 and nonlinear FOM values in the near-IR [31][32][33][34][35]. The n 2 value could be one order of magnitude higher than that in silicon [33], while the nonlinear FOM can be as high as 5 [35], although these may not be obtained simultaneously [34].…”

“…Materials engineering further enhanced the nonlinearity, e.g., in amorphous silicon under certain deposition conditions [31][32][33][34][35] and in Si-rich silicon oxide (SRO) and nitride (SRN) based on the formation of silicon nano-crystals [36][37][38][39][40][41].…”

Nonlinear optical interactions in silicon waveguides

“…Furthermore, it is interesting to note that in a set of experiments involving 150 fs pulses to generate a supercontinuum at telecom wavelengths [45], no degradation could be observed. However, it also needs to be emphasized that other groups have demonstrated aSi:H waveguides, which are chemically stable at telecom wavelengths [36,37]. These groups have shown a multitude of demonstrations of all-optical signal processing experiments in a-Si:H waveguides [36] and even as a source for photon pair generation [46,47].…”