  Unitary operation is an essential step for quantum information processing. We
first propose an iterative procedure for decomposing a general unitary
operation without resorting to controlled-NOT gate and single-qubit rotation
library. Based on the results of decomposition, we design two compact
architectures to deterministically implement arbitrary two-qubit
polarization-spatial and spatial-polarization collective unitary operations,
respectively. The involved linear optical elements are reduced from 25 to 20
and 21 to 20, respectively. Moreover, the parameterized quantum computation can
be flexibly manipulated by wave plates and phase shifters. As an application,
we construct the specific quantum circuits to realize two-dimensional quantum
walk and quantum Fourier transformation. Our schemes are simple and feasible
with the current technology.
