Dong-Jae Shin

Bulk silicon photonic wire for one-chip integrated optical interconnection

We report a nano-sized silicon waveguide by forming partial silicon-on-insulator structure with SPE on bulk silicon substrate. The propagation loss is as low as 6.1 dB/cm, which is close to that of silicon-on-insulator based waveguide.

Mach-Zehnder silicon modulator on bulk silicon substrate; toward DRAM optical interface

We present a Mach-Zehnder silicon modulator fabricated on a bulk silicon substrate featuring active length of 200 µm, modulation speed up to 5 Gb/s, power consumption of 2 pJ/bit, and extinction ratio of 10 dB.

Si-based optical I/O for optical memory interface

Optical interconnects may provide solutions to the capacity-bandwidth trade-off of recent memory interface systems. For cost-effective optical memory interfaces, Samsung Electronics has been developing silicon photonics platforms on memory-compatible bulk-Si 300-mm wafers. The waveguide of 0.6 dB/mm propagation loss, vertical grating coupler of 2.7 dB coupling loss, modulator of 10 Gbps speed, and Ge/Si photodiode of 12.5 Gbps bandwidth have been achieved on the bulk-Si platform. 2x6.4 Gbps electrical driver circuits have been also fabricated using a CMOS process.

10 Gb/s, 1×4 optical link for DRAM interconnect

We present a 10-Gb/s, 1×4 optical link based on a DRAM-integration-ready bulk-silicon modulator for multi-drop CPU-DRAM interconnects. The bulk-silicon modulator operated at 10 Gb/s on a die, and at 5 Gb/s in a QFP package. The 1×4 optical link was limited not by signal integrity but by optical power budget, demonstrating its scalable capacity for the future multi-drop memory bus.

Fabrication and characterization of the Si-photonics-integrated vertical resonant-cavity light-emitting diode

We designed and fabricated a 1.3-um hybrid vertical Resonant-Cavity Light-Emitting Diode for optical interconnect by using direct III-V wafer bonding on silicon on insulator (SOI). The device included InP based front distributed Bragg reflector (DBR), InGaAlAs based active layer, and SOI-based high-contrast-grating (HCG) as a back reflector. 42-uW continuous wave optical power was achieved at 20mA at room temperature.

Germanium p-i-n avalanche photodetector fabricated by point defect healing process

In this Letter, we report Ge p-i-n avalanche photodetectors (APD) with low dark current (sub 1 μA below V(R)=5  V), low operating voltage (avalanche breakdown voltage=8-13  V), and high multiplication gain (440-680) by exploiting a point defect healing method (between 600°C and 650°C) and optimizing the doping concentration of the intrinsic region (p-type ~10¹⁷ cm⁻³). In addition, Raman spectroscopy and electrochemical capacitance voltage analyses were performed to investigate the junction interfaces in more detail. This successful demonstration of Ge p-i-n APD with low dark current, low operating voltage, and high gain is promising for low-power and high-sensitivity Ge PD applications.