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