Quanta image sensor quantum random number generation

Abstract

Some embodiments provide methods and apparatus for quantum random number generation based on a single bit or multi bit Quanta Image Sensor (QIS) providing single-photon counting over a time interval for each of an array of pixels of the QIS, wherein random number data is generated based on the number of photons counted over the time interval for each of the pixels.

1 . A quantum random number generator (QRNG), comprising:
 a Quanta Image Sensor (QIS) comprising a pixel array, wherein each pixel of the QIS is configured to convert photons emitted from a photon source into charged photocarriers, wherein the QIS is configured to readout each pixel to provide a signal representing a count of the number of photocarriers with single-photocarrier sensitivity; and   wherein the QRNG is configured to output random number data having randomness based on the number of collected photocarriers within a time interval.   
     
     
         2 . The QRNG according to  claim 1 , wherein for each pixel the number of photocarriers collected within the time interval is converted to a voltage and then into binary signal using a threshold level. 
     
     
         3 . The QRNG according to  claim 2 , wherein the voltage is compared to the threshold level in the analog domain. 
     
     
         4 . The QRNG according to  claim 2 , wherein the conversion is performed in the digital domain, wherein the photocarrier signal is converted to a digital signal or digital number (DN) by an ADC which has a bit depth higher than 1-bit, and the digital signal or digital number is converted to a 1-bit random number. 
     
     
         4 . (canceled) 
     
     
         5 . The QRNG according to  claim 2 , wherein the photocarrier collection rate and the threshold level are tunable to realize an ideal randomness entropy of the random number data and/or to realize greater than a minimum value of the randomness entropy of the random number data. 
     
     
         6 . The QRNG according to  claim 1 , wherein the photocarrier rate is capable of being adjusted based on the relative location of the photon source to the pixel array. 
     
     
         7 . The QRNG according to  claim 2 , wherein the threshold level can be adjusted by a reference voltage supplied by an on-chip or off-chip DAC. 
     
     
         8 . The QRNG according to  claim 1 , wherein the generated random number data's adjustable levels are periodically or aperiodically reset to maximize randomness entropy. 
     
     
         9 . The QRNG according to  claim 2 , wherein one or more of the following are periodically or aperiodially adjusted to maximize randomness entropy of the random number data: the time interval over which photocarriers are collected, the photon source intensity, and the threshold level used to determine the value of the binary output. 
     
     
         10 . The QRNG according to  claim 1 , wherein the QRNG includes the photon source. 
     
     
         11 . The QRNG according to  claim 1 , wherein the QRNG includes a randomness extractor. 
     
     
         12 . The QRNG according to  claim 1 , wherein the QRNG includes an optical conditioner disposed such that photons emitted by the photon source impinge on the optical conditioner prior to impinging on the pixel array. 
     
     
         13 . A QRNG, comprising:
 a Quanta Image Sensor (QIS) comprising an array of jots that are each configured to provide single-photon detection of photons emitted from a photon source having Poisson photon-emission statistics; and   wherein the QRNG is configured to output random number data, wherein for each jot the number of photons detected by the jot within a time interval is the quantum random variable used for generation of the random number data.   
     
     
         14 . A QRNG comprising:
 a QIS that includes an array of pixels, wherein each pixel is configured to convert a single photon incident on the pixel into a single photocharge-carrier that is stored in the pixel, and wherein the QIS is configured to readout from each pixel, with single-photocharge-carrier sensitivity, the photocharge-carriers, if any, stored in the pixel within a time interval, so as to generate a pixel signal corresponding to the number of stored photocharge-carriers; and   comparison circuitry configured to compare for each pixel, the pixel signal with a threshold level to generate for each pixel a bit having a binary value that depends on whether or not the pixel signal is less than the threshold level or not less than the threshold level, wherein the binary values are substantially equiprobable based on the threshold level, thereby providing for binary output data having high quality randomness.   
     
     
         15 . The QRNG according to  claim 14 , further comprising one or more of (i) a photon source configured to generate the photons incident on the QIS pixel array, (ii) an optical conditioner disposed such that photons emitted by the photon source impinge on the optical conditioner prior to impinging on the pixel array, and (iii) a randomness extractor configured to process data generated from readout of the QIS. 
     
     
         16 . The QRNG according to  claim 14 , wherein the QRNG includes control circuitry configured to adjust or control at least one of (i) the threshold level, (ii) the time interval, (iii) the photon source emission intensity, and (iv) the optical conditioner, to maximize the randomness of the random number data generated by the QIS. 
     
     
         17 . The QRNG according to  claim 14 , wherein each pixel has sufficient in-pixel conversion gain, without in-pixel avalanche gain, to provide for readout of the photocharge with single-electron sensitivity and resolution. 
     
     
         18 . The QRNG according to  claim 14 , wherein the read noise associated with each QIS pixel is at least one of about 0.5 charge carriers rms or less, about 0.3 charge carriers rms or less, and about 0.15 charge carriers rms or less. 
     
     
         19 . A method for quantum random number generation, the method comprising:
 generating for each of a plurality of pixels of a single-bit or multi-bit Quanta Image Sensor (QIS) a signal representing the number of individual photons incident on the pixel over a time interval; and   generating random number data based on the signals representing the number of photons detected over the time interval for each of the pixels.   
     
     
         20 . The ORNG according to  claim 1 , wherein the photon source intensity is tunable to realize an ideal randomness entropy of the random number data and/or to realize greater than a minimum value of the randomness entropy of the random number data.