  We present a practical high-speed quantum random number generator, where the
timing of single-photon detection relative to an external time reference is
measured as the raw data. The bias of the raw data can be substantially reduced
compared with the previous realizations. The raw random bit rate of our
generator can reach 109 Mbps. We develop a model for the generator and evaluate
the min-entropy of the raw data. Toeplitz matrix hashing is applied for
randomness extraction, after which the final random bits are able to pass the
standard randomness tests.
