Superluminescent diodes of the 770–790-nm range based on semiconductor nanostructures with narrow quantum wells

Comparative experimental study of superluminescent diodes (SLDs) with active layers containing one, two, or three 5.0-nm-wide quantum wells symmetrically positioned in the waveguide layer is performed. It is shown that an increase in the number of quantum wells leads to narrowing of the superluminescence spectrum and weakens the dependence of its width on the pump level. Simultaneously, the degree of polarisation of the output radiation noticeably increases. For example, rather reliable high-power narrow-band SLDs with a spectral halfwidth smaller than 8 nm and polarisation ratio TE/TM exceeding 20 dB are developed.