Bloch domain walls in transverse patterns in type-II optical parametric oscillators

Summary form only given. We show that the presence of a birefringent and/or dichroic mirror into a type-II optical parametric oscillator (OPO) yields to a new kind of domain walls. In these walls the field amplitude remains constant while the phase rotates when going from one domain to the neighboring one. These domain walls are similar to Bloch walls in magnetic systems. They appear here for positive or null detunings, where the zero wavenumber is selected. Idler and signal fields show a similar pattern.