Waveguide-Integrated Si Nano-Photodiode with Surface-Plasmon Antenna and its Application to On-chip Optical Clock Distribution

Abstract

We developed a waveguide-integrated Si nano-photodiode (PD) with a surface plasmon (SP) antenna for on-chip optical clock distribution. The interfacial periodic nano-scale metal–semiconductor–metal Schottky electrodes were shown to function as an SP optical antenna and also as an optical coupler between a SiON waveguide and a very thin Si-absorption layer. Furthermore, a very high speed response of 17 ps as well as enhanced photoresponsivity was achieved for a 10-µm coupling length. By using this technology, we fabricated a prototype of a large-scale-integration (LSI) on-chip optical clock system and demonstrated 5 GHz of optical clock circuit operation connected with a 4-branching H-tree structure.

Waveguide-integrated Si nano-photodiode with surface-plasmon antenna and its application to on-chip optical clock signal distribution

“…Results from the FDTD simulation showed more than 60% of coupling efficiency was obtained for wavelengths from 780 to 900 nm [11].…”

“…Input light power is divided into four output ports via MMI splitters, and four Si nano-PDs were coupled with the branching SiON waveguides. Also, Figure 5 (b) and (c) show the transient output waveform of Si nano-PD at 1 V bias, and full width at half maximum (FWHM) of the output waveforms dependence on the dc bias voltage [11]. In this experiment, an optical clock signal of 1 1 1 1 1 1 1 1 1 1 1 1 1. .…”

“…The photoresponse characteristics of the fabricated Si nano-PD is shown in Fig. 3 (c) [11]. An 850-nm-wavelength laser diode (LD) light of 1.6 mW was introduced into the SiON waveguide via butt-coupling with an optical fiber, and the photocurrent was monitored by using a microprobe system with an I-V source meter.…”

“…4 (a) [11]. Input light power is divided into four output ports via MMI splitters, and four Si nano-PDs were coupled with the branching SiON waveguides.…”

Optically-Clocked Instruction Set Extensions for High Efficiency Embedded Processors

“…A remaining problem is that of optical-to-electrical conversion [4] which [3], [5], and [6] have tried to solve with some success. However, much remains to be done in this eld even with the encouraging advances achieved in optical clock distribution at the chip, package, board, and cabinet level [1], [7]- [10].…”