Low-threshold operation of distributed reflector laser with width modulated wirelike active regions

A distributed reflector (DR) laser consisting of an active DFB section and a passive DBR section was realized by modulating widths of wirelike active regions. A threshold current as low as 1.5 mA, a differential quantum efficiency from the front facet of 21% and a sub-mode suppression ratio (SMSR) over 50 dB were realized for a stripe width of 3.4 /spl mu/m and a DFB section length of 150.