Far-field supermode patterns of a multiple-stripe quantum well heterostructure laser operated (∼7330 Å, 300 K) in an external grating cavity

A multiple-stripe quantum well heterostructure laser diode operated in an external grating cavity is shown to exhibit the far-field radiation patterns of the ‘‘supermode’’ eigenstates predicted by coupled mode analysis. Data (∼7330 Å) are presented on a gain-guided laser array at various continuous (cw, 300 K) operating currents to illustrate the progression of the supermodes from double-lobed patterns (phase shift between emitters) to a single-lobed pattern (no phase shift between emitters). As the cavity wavelength is scanned a cyclical progression (2.8-Å period) of far-field patterns (supermodes) is observed.