Si-based On-chip Optical Interconnects
Shang Wang
ECE423 12/16/06
Disadvantages of Electrical Interconnects
Scaling Problem —— ”Aspect Ratio” Limit
T otal R C tim e constant: R l C l l N ow scaling w ith s factor: R l R l s , l sl , C l C l
2 2
N ow T otal R C tim e constant: R l C l l ( R l s ) C l ( sl ) R l C l l T h e sam e!!!
2 2 2 2
R l A , C l B 1 RC A l
2
However, optical interconnects do not have such problem!
Other Advantages of Optical Interconnects
Timing Accuracy Design Simplification
• voltage isolation • Absence of wave reflection and impedance
matching • avoid inductive crosstalk • frequency independence
On-chip Optical Interconnect Data Path
On-chip
Silicon Laser
Silicon Optical Modulator Driver
Silicon Waveguide
Si-based Photo Detector Amplifier
Electrical Logic Cell
Electrical Logic Cell
Si-based Light Source
——Raman Silicon Laser
Simulated Raman Scattering (SRS)
A reversely biased p-i-n diode to eliminate the TPA-induced FCA
Silicon Optical Modulator
N e N h
0 r
et ox t
0.8
[V D V F B ]
ne N e
nh ( N h )
metal-oxide-semiconductor (MOS) capacitor
2 n eff L
Mach-Zehnder Interferometer (MZI)
Si-based Photo detector
SiGe multiple quantum wells (MQW)
Conclusion
The concept of optical interconnect brings a brilliant future for the dense interconnects to the silicon chips. The recent achievement in Intel of the silicon laser, silicon optical modulator and siliconbased photodetector shows the potential of monolithic integration of silicon-based optoelectronics.
Thank you!