About photonic Using Compute Engine with An Optical Phased Array - Page 1
Forum section: electronics / projects

author: Alexander Morozov
author_rank: Newbie
timestamp: June 30, 2023, 03:46:09 pm
content: 1. In the patent "Photonic Ising Compute Engine with An Optical Phased Array" (https://patents.google.com/patent/US20230142781A1/en?q=(Photonic+Ising+Compute+Engine+with+An+Optical+Phased+Array)&oq=Photonic+Ising+Compute+Engine+with+An+Optical+Phased+Array)dated 2023-05-11 and the article "Scalable and ultralow power silicon photonic two-dimensional phased array" (https://pubs.aip.org/aip/app/article/8/5/051305/2893498/Scalable-and-ultralow-power-silicon-photonic-two) dated January 2023, the authors, led by James Leatham from the Raytheon Intelligence & Space laboratory, study the construction of a computer from an optical phased array, and for better control of the electromagnetic field, they propose to use attenuators\amplifiers.2. In “On the control of the electromagnetic field in a space. Continuation” (https://www.eng-tips.com/viewthread.cfm?qid=505072) it is assumed that a periodic array of radio components with wireless distributed communication allows you to control and transform the spatial spectrum of the electromagnetic field only by phase shifters. In the radio range, these can be varicaps, and what's the best thing about optics?Is it useful to combine these two observations when building high-speed optical calculators with vector-matrix control?

author: Alexander Morozov
author_rank: Newbie
timestamp: August 02, 2023, 08:11:09 pm
content: Objectives of the optical computer:- “Optical computing provides an advantage because it generates no heat. It needs no return path for electrons”,- increasing the speed of computing (the clock frequency can be much higher than the units of GHZ of modern electronic computers),- size reduction,- during calculations, the ability to control the electromagnetic field in space as in phased arrays (for frequencies units of GHZ, the dimensions of radio arrays are measured in meters, in optics – in microns),I assume that the classical control of the field by phase shifters\attenuators\amplifiers does not provide control with the greatest benefit for calculations. For example, it is impossible to create a radiation pattern as in FIG. 4 without large energy losses of controlled light using a phased array withFIG. 1. But the diagram withFIG. 2has such an opportunity, if in the optical range it is possible to make a phase shifter with the diagram ofFIG. 3. In this case, the energy is not absorbed \amplified, but redistributed in the control channels. This creates additional opportunities for transmitting binary information.I studied such method of controlling the microwave field in the USSR, but now only technologies are available to mehttps://www.eng-tips.com/viewthread.cfm?qid=460973. For example, JAMES G. LATHAM, head of the RAYTHEON TECHNOLOGIES laboratory, has such technologies and he can make the phased array with diagramFIG. 2.I wrote to them in vain, so I'm trying to find out the opinion of engineers about the usefulness of such field management. Some details are described in the links from the first message.FIG. 1from thehttps://www.semanticscholar.org/paper/A-Monolithically-Integrated-Large-Scale-Optical-in-Chung-Abediasl/5541dd9450564fdd60fdf8fc622246025700a4ba(Fig. 6).FIG. 2, Fig. 3from thehttps://www.eng-tips.com/viewthread.cfm?qid=505072(Fig. 1)

author: Marco
author_rank: Super Contributor
timestamp: August 03, 2023, 12:59:09 pm
content: So is this phase shifting THz electronic signals and then creating photons with nano antennas?

author: Alexander Morozov
author_rank: Newbie
timestamp: August 05, 2023, 08:45:02 am
content: Yes. But it wasn't my idea, it was JAMES G. LATHAM, head of the RAYTHEON TECHNOLOGIES laboratory, deeply respected Cherokee Indian. I only propose to improve the quality of control of the electromagnetic field, including light.

author: Marco
author_rank: Super Contributor
timestamp: August 05, 2023, 11:20:39 am
content: I can kinda sorta see were you are going with this, a 2D power distribution array where the phase shifts determine which antennas get power. I doubt you'll get any useful replies here though.Also you'd really need one phase shifter per cell to show the usefulness of the approach. If the degrees of freedom come from the 1D input of phase shifts, there is no real use to a 2D array of emitters.

author: Alexander Morozov
author_rank: Newbie
timestamp: August 11, 2023, 10:58:03 am
content: That's right, but there are nuances.1. The dielectric lens controls the electromagnetic field in space. Its properties are constant in time.InFIG. 5from the message of July 7, 2020 inhttps://www.eng-tips.com/viewthread.cfm?qid=461144the focusing lens is shown. Pay attention to its sizes. I assume that it is possible to calculate and make such a lens so that at afixedfrequency the diffraction losses will be record low at such sizes. This is useful for transmitting energy over long distances. Micro-CAP12 suggests that if a wide frequency band is needed, for example, for an electromagnetic field with pulse modulation, then it is possible to increase the thickness of the lens and complicate its dielectric structure. At the same time, the thermal losses in the dielectric will increase. I read that there are tasks when the customer agrees to large thermal and diffraction losses for the sake of working in a certain frequency band. Where is the limit of acceptable losses? I don't know.2. On the control of electromagnetic field in time.It was assumed In Soviet textbooks that the controlled power splitter should only to share the energy of the microwave field without phase control, and the phase shifter – on the contrary.FIG. 3is the simplest device that simultaneously control both the coupling factors and the phases in the coupled channels. This is an imitation of the dielectric medium. The refractive index in it changes at the request of the engineer.FIG. 6shows a possible array of phase shifters from coupled resonators. Such resonators are well studied. Their refractive index is changed by heating, changing voltage or current. A circle on the picture may mean a complex structure that provides control of the phase\amplitude of the field and the smallest diffraction scattering. Now such a structures is well simulated in various ways.