Abstract
An alternative design is presented for tunable multiwavelength output using a commercial laser diode array with an external grating cavity. The active medium is a gain-guided 10-strip phase-locked laser-diode array (SDL-2419C). It has high reflectivity (R ≈ 95%) and antireflection coating (R < 0.1%) on the rear and front facets, respectively. An 1800 line/mm grating at grazing incidence provides the mechanism for spectrum narrowing and output coupling of the laser. The laser output spectrum at the maximum and minimum spectral separation of the two-wavelength laser is presented.