Double-pass superluminescent diode with tapered active channel

The optical characteristics of a superluminescent diode (SLD) with a tapered active channel based on a (GaAl)As separate confinement double heterostructure are studied. The one-sided feedback was provided by external reflectors. The cw emission power from the wide-aperture output reached 100 mW, the divergence of the output beam being nearly diffraction-limited. The spectral bandwidth of the emission (the degree of coherence of the SLD) could be varied in a wide range depending on the spectral selectivity of the reflector.