  We study the Josephson effect between weakly coupled d-wave superconductors
within the quasiclassical theory, in particular, the influence of interface
roughness on the current-phase relation and the critical current of mirror
junctions and $45^\circ$ asymmetric junctions. For mirror junctions the
temperature dependence of the critical current is non-monotonic in the limit of
low roughness, but monotonic for very rough interfaces. For $45^\circ$
asymmetric junctions with a linear dimension much larger than the
superconducting coherence length we find a $\sin(2\phi)$-like current-phase
relation, whereas for contacts on the scale of the coherence length or smaller
the usual $\sin\phi$-like behavior is observed. Our results compare well with
recent experimental observations.
