High-density and wide-bandwidth optical interconnects with silicon optical interposers [Invited]

On-chip light sources for silicon photonics

“…Another approach is to reduce the optical coupling loss by realizing the efficient optical coupling between the III-V active layer and the SOI waveguide circuit. Consequently, inverted adiabatic tapers 116,117 and spot size converters (SSCs) 118,119 are widely explored and used in evanescently coupled hybrid lasers and butt-coupled hybrid lasers, respectively. A double adiabatic taper coupler structure 117 was proposed for the efficient evanescent coupling, and over 90% in coupling efficiency can be obtained in a taper length less than 100 mm ( Figure 10).…”

“…A double adiabatic taper coupler structure 117 was proposed for the efficient evanescent coupling, and over 90% in coupling efficiency can be obtained in a taper length less than 100 mm ( Figure 10). For the butt-coupled laser, a novel SSC with a trident Si waveguide (Figure 11a) was demonstrated using a simple fabrication procedure 119 . The coupling loss was as low as 2.3 dB, and the alignment error tolerance was greatly improved in the both horizontal and vertical directions (Figure 11b), effectively enhancing the application of the passive alignment technique for direct mounting integration.…”

Athermal silicon optical interposers with quantum dot lasers operating from 25 to 125°C

“…Athermal silicon optical interposers integrated with quantum dot lasers and other temperature-insensitive components on a single silicon substrate are demonstrated, and error-free data links at 12.5 Gbit/s operating from 25 to 125°C are achieved without any bias adjustment. Since maximum junction temperatures in most LSIs have been below 125°C now and will be in the future, the interposers are tolerant of heat generated by LSIs, and are suitable for inter-chip interconnects.Introduction: We previously proposed a photonics-electronics convergence system to solve bandwidth bottlenecks in inter-chip interconnects and demonstrated silicon optical interposers fully integrated with optical components on a silicon substrate, achieving a high bandwidth density of 30 Tbit/s/cm 2 at room temperature [1]. In practical use, the optical interposers should perform stably under high-temperature conditions and rapid temperature change due to the heat generated by mounted large-scale integration (LSI) chips.…”

“…Introduction: We previously proposed a photonics-electronics convergence system to solve bandwidth bottlenecks in inter-chip interconnects and demonstrated silicon optical interposers fully integrated with optical components on a silicon substrate, achieving a high bandwidth density of 30 Tbit/s/cm 2 at room temperature [1]. In practical use, the optical interposers should perform stably under high-temperature conditions and rapid temperature change due to the heat generated by mounted large-scale integration (LSI) chips.…”

“…We carried out data link experiments with the fabricated athermal silicon optical interposers, which were put on a probe station under temperature control. The experimental setup and procedure were similar to those in [1], except the temperature control. The measured bit error rates (BERs) and eye diagrams from the PD outputs with 12.5 Gbit/s non-return-to-zero signals at various temperatures are shown in Fig.…”