Fast, Compact Random Number Generator Using Semiconductor Lasers

Technological fields
Cutting-edge Technologies
  • Physical random number
  • Semiconductor laser
  • Integrated optical circuit
Laboratory organization
NTT Communication Science Laboratories

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Random number sequences that are absolutely unpredictable are essential for data security, so there is a demand for a compact device that rapidly generates random numbers on the basis of a physical phenomenon. Our work focused on the phenomenon in which the intensity of light from a laser varies randomly over time at high speed. We used the most advanced integrated optical circuit technology and high-frequency packaging technology to achieve a fast and compact random signal generator module. Digitizing the random output signal of the module can produce an unpredictable sequence of random numbers at high speed.


  • Compact, integrated system by using integrated optical circuit technology
  • Random number generation at 2.08 Gbit/s
  • Physical guarantee that generated random number sequence cannot be predicted

Application scenarios

  • Password generation, encryption key generation
  • Generation of random numbers required for the segmentation processing of secret data in secret sharing schemes
  • Generation of key sequences in quantum cryptography
  • Can also be used in numerical computation in science and engineering that uses random numbers