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To: George T. Santamaria who wrote (252)	3/2/1999 8:10:00 PM
From: Frank A. Coluccio	Respond to of 626

Carl, that's ok. I thought it was a different school altogether: Stanford U. <grin> I'm looking forward to the proposed integration effort, too, so we can get to see this in a more everyday kind of light. Regards, Frank C. ps - Sorry, George if I posted this our of sequence... I realized this when I went to edit. Don't know how that happened.

To: George T. Santamaria who wrote (252)	3/4/1999 5:46:00 AM
From: Carl Hindman	Read Replies (3) \| Respond to of 626

George Santamaria writes: "You see, upon reading the paper, it becomes apparent that this technology purports to work by modulating data in whatever form -- analog, 64 QAM digital or whatever onto subcarriers at various microwave frequencies. The subcarriers and their modulating signals are chosen so that they occupy adjacent bands in the RF spectrum. For example, if channels are stacked together so that they fill up 20GHz of spectrum, then it ought to be possible to encode a total of 100-160GB of data if the individual channels are modulated with a 256 QAM technique. I want to point out that this type of channel stacking is purported, in the white paper, to be be done before any electro-optical modulation is performed on the output laser beam." Yes I noticed this also. They are using single sideband modulation (without carrier suppression) and a frequency division muxing for the electrical arrangement. Your estimate of 100-160GB from a 256 QAM for 20GHz of bandwidth does require 8 bit (48 dB+) SNR at the receiver however. Furthermore other remarks made by SR indicates that they can independently 'focus' each channel so the above is not telling us anything about how the optical signal is (de)modulated by this composite signal, which IMO is the heart of the whole deal assuming that it is real. I surmise that the frequency tags' mentioned in the PR however may just be the unsupressed carriers of the FDM muxed SSB. "The paper also says that the above RF signal is applied to the electro-optical crystal which performs an amplitude modulation. There is a vague description of the modulator, at best. What is perfectly clear, however, is that information could be transmitted on a light beam at these data rates with QAM encoding and plain, old-fashioned AM modulation techniques applied to a very narrow linewidth laser beam." Yes but direct AM modulation of a clean CW carrier is not so easy to achieve with an EO or AO modulator at these bandwidths as the modulators are usually uniaxial or biaxial optically active crystals with high electo-strictive responses. These make it easy to modulate polarization but not amplitude directly. However you could be right. I would also point out though that SR claims to be relatively more immune from propagation dispersion in the fiber continues to suggest that, at least at the receiver end, they have a means of isolating the signal subchannels optically because, assuming the required selectivity, (which is considerable), they would only be susceptible to intrachannel dispersion which would be much lower than that across the entire signal bandwidth. Once again the use of high order signalling constellations to increase bits/Hz depends upon attaining an adequately high SNR at the receiver. "There appears to be no use of or even the need to use multiple LaGuerre orders or any kind of stacking of photons in three-dimensional space. If photons were being stacked in independent Laguerre Orders, as the entrepreneuers claim, then there would need to be an independent electrical stimulus for each order. Where is the unique role that ORS will play? Hence, where are the cattle?" Since photons are bosons, they easily 'stack' in whatever space you can put them in. Mention of this is just more SR red herring. However, what if we assume that the action of the modulator is to 'wind up' each subcarrier mode of the beam into a set of angular momentum states which are disjoint from one subcarrier to the next simply on the basis of the frequency of the subcarrier. I am thinking here of an angular momentum analog to the 'coherent states' connecting photon momentum eigenfunctions to classical plane wave fields. I am conjecturing that it is possible to modulate the principle indices of an anisotropic propagation medium to accomplish this. The resultant EM field would exhibit a Poynting vector which winds around optical axis at the corresponding frequency(s). The action of the demodulator would then be (hypothetically) to 'unwind' a particular set of such states into coherent superposition for that subcarrier, but which would be highly interfering or incoherent for the other subcarriers. The particular signal could then be detected without having to convert the whole optical signal space to an electrical signal to bandpass out the desired channel. Clearly this would simplify add/drop etc. Obviously this is just my conjecture based upon an attempt to be consistent with SR's various rather misleading remarks, without obviously violating physics. The question remains as to whether this or an analogous type of modulation is possible, how it is achieved and how the relevant signal characteristics can be preserved through insertion of the optical signal from the modulator into the fiber and vice versa.For instance the 'helical' modes should couple into the fiber so long as the departure of the Poynting vector from the optical axis reamins within the numerical aperture of the fiber. Just from simple ray tracing one can surmise that these 'off-axis' rays will continue to bounce around in the fiber maintaing the progression of the P vector rotation ie. the angle (I think). At the receiver application of the the 'conjugate' of the carrier (via some external synchronizing signal) will 'straighten' out the modulated frequency selected while leaving all others at slight angles which then allows the preferred signal to be focussed onto the photodiode while dispersiing the other signals into off axis positions in the focal plane. Again all highly conjectural on my part but I again also consistent with the general tenor of SR's highly evasive hints. You can see that I am trying to credit SR with more than simply having a clean CW source to which conventional modulation schemes, appropriate to scalar wave propagation, could be applied because both you and I know that any such arrangement is immediately subject to the usual trades along Shannonian lines vs alternatives, does not represent a significant breakthrough conceptually or technologically and probably would not much simply equipment requirements. I also think that my surmise is consistent with SRs very cagey approach to disclosure, since the basic phenomenology, if correct, is just the behavior of EM fields in anisotropic inhomogeneous media and belongs to mother nature not SR. Since the physics is clearly not a candidate for statutory material, SR holds their cards close to the vest while applying for patents on the more obvious 'embodiments'. To see if I am right we would need to review solutions to Maxwells equations for inhomogenous anisotropic media and how such solutions couple into typical optical fibers. This is more than just a day or two's homework but would seem to be worth a look. OK George, AHaha et al what do you think? Carl

To: George T. Santamaria who wrote (252)	3/5/1999 9:45:00 PM
From: Srexley	Read Replies (1) \| Respond to of 626

Hello everyone, I am using this response as my first post to this thread. I have been following this thread since it's insecption, and it is getting so interesting, I decided to join s.i. and join in the discussion. My response has to do with patent protection and SR's release of information on their technology (white paper, DQ report, news releases). People who have speculated about their strategy have suggested some of the information is intended to mislead or confuse. I will use George's statement as an example: "There appears to be no use of or even the need to use multiple LaGuerre orders or any kind of stacking of photons in three-dimensional space. If photons were being stacked in independent Laguerre Orders, as the entrepreneuers claim, then there would need to be an independent electrical stimulus for each order. Where is the unique role that ORS will play? Hence, where are the cattle?" I am not at the technical level of most (if not all) of the people on this thread, but I have a decent since of logic and am at least smart enough to follow what's going on. That said, my feeling is that Dr. Palmer's figuring out a way of to use multiple LaGuerre orders for the stacking of photons in 3 deminsional space IS the breakthrough. To accomplish this feat he needed a contraption that could transmit this technology (stabelized laser), and that is what the patent is for. Even if someone invented a better mouse trap, I'm not sure they would have a way of modulating the information onto the beam as good as SR's. In other words, I think that what SR says is basically true, but they are not telling everything (like the solutions to the Maxwell equations). What do you think? Don't laugh too hard if I'm way off base. This is my first post, and I don't want to look like a chump.