Hybrid coupling in integrated injection laser arrays

Analytic and numerical investigations are reported of the mode composition of the radiation emitted by integrated injection laser arrays consisting of an arbitrary number of components coupled by Y junctions and by a slight overlap of the fields of parallel parts of waveguides. An analysis of symmetric Y couplers is made also near the lasing threshold. A strong dependence of the mode composition of the output radiation on the weak coupling between the parallel waveguides and/or on the waveguide length is revealed. An allowance for weak coupling in Y-coupler arrays alters considerably the distribution of the radiation intensity of the first array mode in the far-field zone and the changes are manifested mainly by a relative increase of the side lobes of the angular distribution of the output radiation.