Low-loss submicrometer silicon-on-insulator rib waveguides and corner mirrors

Abstract

Rib microwaveguides are demonstrated on silicon-on-insulator substrates with Si film thickness of either 380 or 200 nm and a width of 1 microm. Corner mirrors that allow compact 90 degrees turns between two perpendicular waveguides are characterized. Measured propagation losses are approximately 0.4 dB/cm and approximately 0.5 dB/cm for 380-nm and 200-nm Si film, respectively, and mirror losses are approximately 1 dB. This allows the development of applications such as optical interconnects in integrated circuits over propagation distances larger than several centimeters.

Compact and Highly Efficient Grating Couplers Between Optical Fiber and Nanophotonic Waveguides

“…Traditional grating couplers have a small coupling strength and are therefore rather long and have a small bandwidth. A coupling efficiency of 40% was reported in [4]. By using a top mirror and coupling through the substrate, a coupling efficiency of 57% was demonstrated in [5].…”

Unidirectionally optical coupling from free space into silicon waveguide with wide flat-top angular efficiency

“…In practice, the triangular pattern are approximated by 20-step staircases. As the design and fabrication of the taper and photonic wire has a well-rounded study [8,9,24], here we focus on the design of the grating, which can be fabricated using state-of-the-art techniques just as stated above, to achieve wide flat-top angular efficiency.…”

Efficient light coupling from integrated single-mode waveguides to supercollimating photonic crystals on silicon-on-insulator platforms

“…The high index contrast between Si and silica (SiO 2 ) makes it possible to design efficient planar PhCs and lowloss waveguides. Rib waveguides 17 in particular consist of a waveguide core surrounded by a partially etched Si layer, contrary to strip or ridge waveguides, where the surrounding Si layer if etched down to the SiO 2 layer. Rib waveguides have the capability of sustaining TE-and TM-like single-modes that exhibit a larger spatial extension than other SOI-based waveguides.…”

“…One should note that a thickness of 700 nm is sufficient for the SiO 2 layer below the guiding Si layer to prevent light from leaking down to the Si substrate 17 . The period a of the lattice is 310 nm and the radius r of the holes is 94 nm.…”