Highly efficient double-taper-type coupler between III–V/silicon-on-insulator hybrid device and silicon waveguide

Abstract

An optical mode converter between hybrid device and Si waveguide is the key component for efficient and stable operation of III–V/silicon-on-insulator (SOI) hybrid photonic integrated circuits (PICs). In this study, we introduced a double taper structure into such a mode converter and investigated the coupling efficiency dependence on their structural parameters. By using N2 plasma activated bonding technology, III–V/SOI double-taper-type mode couplers with various taper-tip-widths and taper lengths were fabricated, and their coupling efficiencies were evaluated. As the result, a coupling efficiency of as high as −0.2 dB was achieved for a double-taper device with a tip width of 0.4 µm and total length of 85 µm.

III–V gain region/Si waveguide hybrid lasers by chip-on-wafer hydrophilic bonding process using UV-ozone treatment

“…8(c)]. 46) In order to acquire both high-efficiency optical coupling to the Si waveguide and the constriction of a current-injection region, the p-type tapers have a two-storied ridge structure in which a taper waveguide with a deep ridge and a gain region with a shallow ridge are connected. The details of this structure are described in our previous paper.…”

Design and characteristics of reflectivity tunable mirror with MZI and loop waveguide on SOI

“…Our group used a rib waveguide with a thin remaining Si layer to obtain a hydrophobic surface for wafer bonding. 28) The hydrophobic surface is preferable to have a good bonding interface without water void for III-V/Si heterogeneous integration as our final target of hybrid lasers. Since we only have a thickness of 30 nm, the design can be applicable with small modification for conventional channel waveguide.…”

“…[23][24][25][26] We have also reported a GaInAsP/SOI hybrid laser using a III-V/SOI hybrid gain section and Si waveguide resonators using direct bonding technology. [27][28][29][30] As mentioned earlier, there have been several reports on photonic FPGAs or R-PICs. These PICs consist of only passive elements such as waveguides; 10,11) there are only a few reports of photonic FPGAs that include light sources and active elements.…”

III–V gain region/Si waveguide hybrid lasers with InP-based two-storied ridge structure by direct bonding technology

“…In order to realize a III-V/Si hybrid integration platform, various approaches, such as the bonding of processed III-V chips, [16][17][18] transfer printing, [19][20][21] bonding using polymers, [22][23][24] and direct bonding [25][26][27][28][29][30] have been studied. The direct bonding process of a III-V wafer on a silicon-oninsulator (SOI) substrate has several advantages over other approaches, since it offers high optical coupling efficiency between III-V layers and Si waveguides [31][32][33] and does not need severe position alignment in the bonding process, i.e. the position alignment of III-V layers and Si waveguides is determined by a conventional photolithography technique after the bonding process.…”

“…34) The high optical coupling efficiency between InP-based layers and Si-waveguides using two-step taper structures has also been suggested. [31][32][33] To obtain good properties in hybrid lasers, a new waveguide configuration which attains both high optical coupling efficiency at the interface between III-V layers and Si waveguides and current-blocking for an efficient current injection to the active region is a key point, so we introduce a two-storied ridge structure consisting of a taper waveguide with a deep ridge and a gain region with a shallow ridge for hybrid lasers.…”