  We propose a linear optical quantum computation scheme using time-frequency
degree of freedom. In this scheme, a qubit is encoded in single-photon
frequency combs, and manipulation of the qubits is performed using
time-resolving detectors, beam splitters, and optical interleavers. This scheme
does not require active devices such as high-speed switches and electro-optic
modulators and is robust against temporal and spectral errors, which are mainly
caused by the detectors' finite resolution. We show that current technologies
almost meet the requirements for fault-tolerant quantum computation.
