Breaking News
Comments
Newest First | Oldest First | Threaded View
Page 1 / 3   >   >>
R_Colin_Johnson
User Rank
Author
re: IBM debuts CMOS silicon nanophotonics
R_Colin_Johnson   12/13/2010 5:11:40 PM
NO RATINGS
For a direct bandgap material, like III-V, an electron near the bottom of the conduction band can recombine with a hole is near the top of the valence band, annihilating the electron and releasing its energy as a photon. Unfortunately, in an indirect band gap material such a process would violate the conservation of crystal momentum.

R_Colin_Johnson
User Rank
Author
re: IBM debuts CMOS silicon nanophotonics
R_Colin_Johnson   12/13/2010 4:49:05 PM
NO RATINGS
That, of course, is one of the issues that IBM engineers are working on as we speak. And you can bet IBM is also working on process/material/archtectural innovations to overcome the hurdles to silicon emitters.

krisi
User Rank
Author
re: IBM debuts CMOS silicon nanophotonics
krisi   12/13/2010 3:38:36 PM
NO RATINGS
thank you Colin...this approach seems to be much more practical...but clearly some issues remain, how do you synchronize off chip III-V laser signals with some on chip CMOS generated signals? Kris

R_Colin_Johnson
User Rank
Author
re: IBM debuts CMOS silicon nanophotonics
R_Colin_Johnson   12/12/2010 7:31:59 PM
NO RATINGS
Yes, Intel has successfully grafted a flake of III-V onto a silicon chip as an emitter, but not in a production environment. I believe that instead of fabricating III-V materials on CMOS chips, that instead IBM is figuring on using a traditional discrete III-V emitter and just piping its emissions onto its CISN chips with fiber optics, where the silicon modulators will take over translating electrical data into optical data.

R_Colin_Johnson
User Rank
Author
re: IBM debuts CMOS silicon nanophotonics
R_Colin_Johnson   12/12/2010 7:23:58 PM
NO RATINGS
Good emitters need to have a direct bandgap so that electrons in the conduction band can annihilate a hole in the valence band, thereby releasing the excess energy as a photon. Silicon has an indirect bandgap that prevents it from being a good emitter.

krisi
User Rank
Author
re: IBM debuts CMOS silicon nanophotonics
krisi   12/11/2010 12:12:08 AM
NO RATINGS
No, silicon has indirect bandgap, that is the whole problem...you really have to twist its bonds to produce coherent light...regardless of the wavelength...Kris

R_Colin_Johnson
User Rank
Author
re: IBM debuts CMOS silicon nanophotonics
R_Colin_Johnson   12/10/2010 11:58:07 PM
NO RATINGS
I thought of this idea of using air-gaps as waveguides when I was interviewing IBM, but then forgot to ask about it. My best guess is that the people working on air-gaps are not in the same huddle as the guys working on silicon photonics. Maybe when both technologies are a little more mature, there will be some cross-fertilization.

R_Colin_Johnson
User Rank
Author
re: IBM debuts CMOS silicon nanophotonics
R_Colin_Johnson   12/10/2010 11:52:50 PM
NO RATINGS
Intel has many of the components for silicon photonics, including a hybrid emitter that uses a III-V flake, but IBM claims it is the only vendor that has downsized its photonic components enough to make them commercially feasible.

krisi
User Rank
Author
re: IBM debuts CMOS silicon nanophotonics
krisi   12/10/2010 11:50:55 PM
NO RATINGS
Thank you Colin. Yes, silicon emitter would have poor performance, carbon nanotube based or else (BTW, carbon nanotube laser sounds like a long shot)...and III-V laser would be lower cost, but only if manufactured in III-V process...I think it will be very expensive if manufactured in silicon process, imagine how many process steps will be require to add that laser, enormous complexity, hardly a manufacturable solution! Kris

R_Colin_Johnson
User Rank
Author
re: IBM debuts CMOS silicon nanophotonics
R_Colin_Johnson   12/10/2010 11:45:12 PM
NO RATINGS
IBM has a silicon emitter, but it is a hybrid that uses a carbon nanotube: htp://bit.ly/eHrLjj However when I asked IBM about it, they said cost-wise no silicon emitter could yet compete with III-V emitters in performance or cost, and until they do no one should switch.

Page 1 / 3   >   >>


Radio
LATEST ARCHIVED BROADCAST

What are the engineering and design challenges in creating successful IoT devices? These devices are usually small, resource-constrained electronics designed to sense, collect, send, and/or interpret data. Some of the devices need to be smart enough to act upon data in real time, 24/7. Specifically the guests will discuss sensors, security, and lessons from IoT deployments.

Brought to you by:

Datasheets.com Parts Search

185 million searchable parts
(please enter a part number or hit search to begin)
Like Us on Facebook
Special Video Section
With design sizes expected to increase by 5X through 2020, ...
01:48
Linear Technology’s LT8330 and LT8331, two Low Quiescent ...
The quality and reliability of Mill-Max's two-piece ...
LED lighting is an important feature in today’s and future ...
05:27
The LT8602 has two high voltage buck regulators with an ...
05:18
Silego Technology’s highly versatile Mixed-signal GreenPAK ...
The quality and reliability of Mill-Max's two-piece ...
01:34
Why the multicopter? It has every thing in it. 58 of ...
Security is important in all parts of the IoT chain, ...
Infineon explains their philosophy and why the multicopter ...
The LTC4282 Hot SwapTM controller allows a board to be ...
This video highlights the Zynq® UltraScale+™ MPSoC, and sho...
Homeowners may soon be able to store the energy generated ...
The LTC®6363 is a low power, low noise, fully differential ...
See the Virtex® UltraScale+™ FPGA with 32.75G backplane ...
Vincent Ching, applications engineer at Avago Technologies, ...
The LT®6375 is a unity-gain difference amplifier which ...
The LTC®4015 is a complete synchronous buck controller/ ...
10:35
The LTC®2983 measures a wide variety of temperature sensors ...
The LTC®3886 is a dual PolyPhase DC/DC synchronous ...