Subwavelength grating slot (SWGS) waveguide on silicon platform

Abstract

We present a subwavelength grating slot (SWGS) waveguide on silicon platform. The SWGS waveguide is characterized by the merging of a slot structure and a subwavelength grating (SWG) structure. The mode guiding mechanism (SWG slot mode) relies on the combination of surface enhanced supermode (slot mode) in a slot waveguide and Bloch mode (SWG mode) in an SWG waveguide. The mode properties and nonlinearities of silicon-based strip waveguide, slot waveguide, SWG waveguide and SWGS waveguide are studied in detail for comparison. It is found that the designed SWGS waveguide with SiO/air cladding features greatly reduced nonlinearity due to the delocalized light from the silicon region. We also optimize the SWGS waveguide with varied geometries (silicon width, slot width, period, duty cycle) using the mode confinement factor and evaluation factor. An ultralow nonlinearity of 3.20 /W/m is obtained. Moreover, we design two types of compatible strip-to-SWGS mode converters, showing favorable performance with broadband high conversion efficiency. The obtained results indicate that the proposed SWGS waveguide with greatly reduced nonlinearity may find potential applications in chip-scale data transmission for optical interconnects. The SWGS waveguide with air cladding or low-refractive-index nonlinear material cladding may also see possible applications in optical sensing and nonlinear optical signal processing.

Recent Advances in Resonant Waveguide Gratings

“…Photonic integrated circuits or integrated optical circuits are devices which integrate two or more photonic functions in a similar way to integrated electronic circuits, but using photons rather than electrons. Relaxed latency, wide bandwidth, and high resistance to electromagnetic interferences are some of the promising driving forces behind the development of such platforms . As discussed earlier, RWG were initially developed as thin‐waveguide couplers in the 1970s following the work of Dakss et al .…”

“…Relaxed latency, wide bandwidth, and high resistance to electromagnetic interferences are some of the promising driving forces behind the development of such platforms. [276] As discussed earlier, RWG were initially developed as thin-waveguide couplers in the 1970s following the work of Dakss et al [9] and the state of the art was reviewed by Tamir in 1975 [28] and by Petit in 1980. [29] Optical interconnects with higher efficiency and lower coupling losses than using micro-mirrors have been measured.…”

On-chip silicon photonic signaling and processing: a review

“…In this section, we first introduce several kinds of silicon waveguide structures, and then review their applilcations in on-chip signal photonic signaling [135,136,146,147,224,225].…”

“…We evaluate the performance of high-speed on-chip signal transmission of silicon strip waveguides (e.g. microring formed by strip waveguides), silicon slot waveguides, hybrid SPP slot waveguides, and SWGS waveguides [135,136,146,147,224,225].…”

“…As mentioned above, the SWGS waveguide with low index air or SiO 2 slot region, adding increased degree of freedom and flexibility for tailoring mode with much lower nonlinearity, is also a promising candidate for on-chip optical interconnects. We design an SWGS waveguide on silicon platform [224], as shown in Fig. 13.…”