Abstract: The invention is directed to an integrated (2.times.2) optical coupler including input waveguides (21, 22) approaching each other at an angle .PHI. and having different propagation constants and widths (w.sub.1, w.sub.2), minimum web widths S (approximately 4 .mu.m) and output waveguides (23, 24) of the same width w.sub.0. The output waveguides include circular arc segments which connect to the respective input waveguides with abrupt steps. Both directions are the same. Attenuation is avoided where the waveguides come close to each other in the interaction region and arcuate segments in the narrow waveguide 21 are avoided. The optical coupler according to the invention can be used in branching devices and especially in a 2.times.N branching device and in Mach-Zehnder duplexers.