A Matrix-Grating Equivalent Phase Shifted Laser Array With 25-nm Wavelength Tuning Range

A matrix-grating equivalent phase shifted (MG-EPS) eight-wavelength distributed-feedback (DFB) semiconductor laser array is experimentally demonstrated. This device contains eight index-coupled DFB semiconductor laser diodes with a Y-junction combiner, which have wavelength channel spacing of
$\sim 3.37$
nm, with quarter-wave EPS structures. 25-nm continuous wavelength tuning range is achieved by changing the temperature, with side mode suppression ratios >42 dB within the entire tuning range. Meanwhile, because of the quarter-wave equivalent phase shift structures, no mode-hopping problems have been observed and good single-longitudinal mode operation is achieved. This device is promising for cost-effective applications of wavelength division multiplexing systems.