摘要:
An adjustable CCD gate structure utilizing ultra-violet light activated floating gates, wherein a floating polysilicon gate is used between a CCD electrode and the underlying substrate to provide a fixed voltage bias to the CCD gate during the manufacturing process thereof The floating gate is programmed with a desired voltage bias during the application of ultra-violet light and is thereafter fixed at that adjusted level, upon the removal of the ultra-violet light. Thus, the method of the present invention comprises the steps of providing a CCD gate structure in which there is such a floating polysilicon gate between the CCD electrode and the underlying substrate; applying an ultra-violet light activation to the floating polysilicon gate; applying a voltage to the conventional CCD electrode which is resistively coupled to the floating electrode for adjusting the bias on the floating electrode to a desired level; and then removing the ultra-violet light to fix the voltage bias at the floating polysilicon gate at a permanant level.
摘要:
A synapse for neural network applications providing four quadrant feed-forward and feed-back modes in addition to an outer-product learning capability allowing learning in-situ. The invention, in its preferred embodiment, utilizes a novel two-transistor implementation which permits each synapse to be built in an integrated circuit chip surface area of only 20 by 20 micrometers. One of the two transistors at each synapse of the present invention comprises a floating gate structure composed of a floating gate electrode and a control electrode which permits learning upon application of incident ultraviolet light. During ultraviolet light application, a floating gate electrode voltage may be altered to modify the weight of each synapse in accordance with preselected criteria, based upon the input and output weight change vector elements corresponding to that particular matrix element. The second transistor corresponding to each synapse of the present invention provides a novel method for applying a voltage to the control electrode of the aforementioned floating gate structure of the first transistor. The voltage applied to the control electrode and thus the proportionate change in the floating gate electrode of the first transistor may be made proportional to the product of the corresponding input weight change vector element and the corresponding output weight change vector element, by using slope controllable ramp generators and phase controllable pulse generators, only one set of which must be provided for the entire matrix of synapses herein disclosed.
摘要:
A charge domain bit serial vector matrix multiplier for real time signal processing of mixed digital/analog signals for implementing opto-electronic neural networks and other signal processing functions. A combination of CCD and DCSD arrays permits vector/matrix multiplication with better than 10.sup.11 multiply accumulates per second on a one square centimeter chip. The CCD array portion of the invention is used to load and move charge packets into the DCSD array for processing therein. The CCD array is also used to empty the matrix of unwanted charge. The DCSD array is designed to store a plurality of charge packets representing the respective matrix values such as the synaptic interaction matrix of a neural network. The vector multiplicand may be applied in bit serial format. The row or sensor lines of the DCSD array are used to accumulate the results of the multiply operation. Each such row output line is provided with a divide-by-two/accumulate CCD circuit which automatically compensates for the increasing value of the input vector element's bits from least significant bit to most significant bit. In a similar fashion each row output line can be provided with a multiply-by-two/accumulate CCD circuit which automatically accounts for the decreasing value of the input vector element's bits from most significant bit to least significant bit. The accumulated charge packet output of the array may be preferably converted to a digital signal compatible with the input vector configuration by utilizing a plurality of analog-to-digital converters.
摘要:
Several embodiments of neural processors implemented on a VLSI circuit chip are disclosed, all of which are capable of entering a matrix T into an array of photosensitive devices which may be charge coupled or charge injection devices (CCD or CID). Using CCD's to receive and store the synapses of the matrix T from a spatial light modulator, or other optical means of projecting an array of pixels, semiparallel synchronous operation is achieved. Using CID's, full parallel synchronous operation is achieved. And using phototransistors to receive the array of pixels, full parallel and asynchronous operation is achieved. In the latter case, the source of the pixel matrix must provide the memory necessary for the matrix T. In the other cases, the source of the pixel matrix may be turned off after the matrix T has been entered and stored by the CCD's or CID's.
摘要:
A non-destructive charge domain multiplier and process thereof wherein the unique characteristics of the charge coupled device permits sensing the size of the charge packet as it moves past an electrode and creating a new charge packet proportional to the product of the original packet and an externally applied value. The device non-destructively senses the size of the charge packet and multiplies it with another value using a multiple metering gate variation of the "Fill and Spill" technique. The present invention therefore constitutes a unique CCD configuration which creates as an output, a charge packet proportional to the product of the charge in an input packet and an externally applied value. Thus, the present invention enables the performance of non-linear operations by CCD integrated circuits.
摘要:
A fully parallel CCD memory chip of N address lines which detects in just one clock cycle, a perfect match between an input pattern and any of a plurality of stored patterns and also detects in less than (N+1)-comparison cycles and still just one XOR operation, the best matching in case a perfect one does not exist. The chip disclosed herein has a fully parallel architecture in which an input word is compared to all stored words at one time. A preferred embodiment of the invention uses a four phase CCD, wherein each stored word occupies one row of the CCD and each such bit of each such word occupies two cells. Where perfect matches exist, only one comparison clock cycle is needed to compare the input word with all stored words and where there is no perfect match, the best match will be detected on a subsequent comparison pulse. Charge packets represent binary words generated by external pulses that are applied to the chip through data input lines and then are compared to the data applied to the address lines. The sensing is done directly on the cells in a non-destructive sensing process in parallel, rather than at the end of each row.
摘要:
A laser power grid for operation with data networks employs WDM and incorporates wavelength addressing. The laser power grid (100) includes a laser power supply station (110) comprising a plurality of continuous-work laser sources (112, 114, 115, 116, 118), a laser distribution grid (130) for distributing light propagations of different wavelengths throughout a data network and an optical switching network (142, 144, 145, 146, 148) coupled to the laser distribution grid for locally turning the laser power on when it is needed. The laser power grid replaces systems of tunable lasers. It is considerably faster and cheaper than systems of tunable lasers and produces less waste heat within the data network surroundings. The laser power grid incorporates parallel fast optical communication in complex multi-node communication and computer networks and enables the implementation of burst switching and packet switching by wavelength addressing.
摘要:
The present invention relates to an optical switch comprising a paraelectric photorefractive material, storing a hologram, possibly a latent hologram, whose reconstruction, or activation and reconstruction, is controllable by means of an applied electric field. The hologram may be formed by spatial modulation of the refractive index of the paraelectric photorefractive material, which arises from the quadratic electro-optic effect induced by the combined action of a spatially modulated space charge within the paraelectric photorefractive material and an external applied electric field. The present invention further relates to a switching network, such as a multistage network, for use in an optical communications system, incorporating at least one optical switch according to the invention.
摘要:
Methods for permanently introducing patterns in electro-optic crystals are provided, by forming patterned variations in the composition of the electro-optic crystals [28], during the crystal growth process. These methods open a way to a family of light-controlling devices that can operate at temperatures as high as 80 degrees centigrade, and may be stored at temperatures as high as 300 degrees centigrade. Additionally, they may withstand radiation of natural light and cosmic ray. In accordance with one embodiment, an electrically [76] controlled Bragg grating is introduced into a crystal, by a permanent periodic spatial variation [60] of its composition, forming permanent periodic striations. The periodic striations induce a spatial modulation of the dielectric constant, and the application of a uniform electric field produces an induced polarization grating.