  We propose a scalable scheme for optical quantum computing using
measurement-induced continuous-variable quantum gates in a loop-based
architecture. Here, time-bin-encoded quantum information in a single spatial
mode is deterministically processed in a nested loop by an electrically
programmable gate sequence. This architecture can process any input state and
an arbitrary number of modes with almost minimum resources, and offers a
universal gate set for both qubits and continuous variables. Furthermore,
quantum computing can be performed fault-tolerantly by a known scheme for
encoding a qubit in an infinite dimensional Hilbert space of a single light
mode.
