Re: [802.3_100GNGOPTX] copper and optics differences
Jeff and Chris,
Just to provide some context to discussion, here are the links to the entire Gazettabyte interview with Mehdi. Part 1: http://www.gazettabyte.com/home/2012/10/16/silicon-photonics-qa-with-koturas-cto.html. Part 2: http://www.gazettabyte.com/home/2012/10/17/qa-with-koturas-cto-integration-styles-and-io-limits.html.
And no, it was not raining cats and dogs when Mehdi did the interview. Photons and electrons have always behaved like cats and dogs!
Arlon
-----Original Message-----
From: Jeffery Maki [mailto:jmaki@xxxxxxxxxxx]
Sent: Tuesday, October 23, 2012 4:11 PM
To: STDS-802-3-100GNGOPTX@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_100GNGOPTX] copper and optics differences
Chris,
Simulation tools can prove what does not work. The addition of finer fidelity to simulation tools does not usually lead to something becoming feasible when first found to be faulty with first principles. Proving something works is something much different and getting "excellent first pass correlation with measurements" is indeed years ahead and dependent on much forward refinement of tools.
Jeff
-----Original Message-----
From: Chris Cole [mailto:chris.cole@xxxxxxxxxxx]
Sent: Tuesday, October 23, 2012 3:43 PM
To: STDS-802-3-100GNGOPTX@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_100GNGOPTX] copper and optics differences
Jeff,
If you pushed dogs close enough together, they would revert to their primal instincts and fight their way out like wolves. However, when taken for a confined stroll along spacious copper wires, they are happy to please their electronic design masters through obedient behavior.
I agree with you that optical chip EDA tools have the potential in the future for excellent first pass correlation with measurements, if we can overcome the resource and volume limitations that Michael Hotchberg discusses. However, it is a mistake to confuse what is possible in the future with reality today. Even worse is to act on that confusion.
Chris
-----Original Message-----
From: Jeffery Maki [mailto:jmaki@xxxxxxxxxxx]
Sent: Tuesday, October 23, 2012 2:53 PM
To: Chris Cole; STDS-802-3-100GNGOPTX@xxxxxxxxxxxxxxxxx
Subject: RE: copper and optics differences
Chris,
I agree but something seems confused:
Photons are bosons and can occupy the same quantum state. Electrons are fermions and cannot occupy the same quantum state. I think electrons would thus be more like cats as they tend to fly apart the more you push them together into the same place at the same time.
The precision to which optical theory can match experiment can be quite pleasing if not astounding. The problem is capturing all the relevant physical phenomena. It is called "design to process" for a component that provides the challenge. It is quite intensive to develop a model of what a given micro-fabrication facility produces that captures everything such as stress induced birefringence, density variations, scattering from imperfections in lithography, the list goes on. Success with this approach has been established. The direct evidence is sub-wavelength optical lithography itself for electronics. Still, I do get the point you make.
What I do believe we have an opportunity to do is to develop an impairment model to compare the robustness of signal propagation over the fiber media including patch panels. This could potentially be done using RSoft OptSim, VPI, or other tool with the appropriate model being setup. Then we might have a means for objectively comparing reception and the resulting BER of competing proposals for signaling.
Jeff
-----Original Message-----
From: Chris Cole [mailto:chris.cole@xxxxxxxxxxx]
Sent: Tuesday, October 23, 2012 10:41 AM
To: STDS-802-3-100GNGOPTX@xxxxxxxxxxxxxxxxx
Subject: [802.3_100GNGOPTX] copper and optics differences
In the Next Generation Optical Ethernet Study Group, a number of presentations heralded the arrival of optical simulation tools that will rival the modeling accuracy of IC simulation tools, leading to first pass success of complex optical chips. Those of us that have been through multiple iteration cycles designing even simple optics have remained skeptical that our jobs are soon going to be a lot easier. This has been reaffirmed by presented measurements.
A recent quote from Mehdi Asghari, CTO of Kotura, wonderfully captures the difference between designing electronics and optics.
"Photons and electrons are like cats and dogs. Electrons are dogs: they behave, they stick by you, they are loyal, they do exactly as you tell them, whereas cats are their own animals and they do what they like. And that is what photons are like."
If you find the cat herding analogy too simplistic an explanation, I am confident Mehdi can expand using quantum statistical mechanics.
Chris