Narrow linewidth 1.55 µm laterally-coupled DFB lasers fabricated using nanoimprint lithography

We report on the use of nanoimprint lithography for the fabrication of InP-based laterally-coupled ridge waveguide distributed feedback laser diodes (LC-DFB LDs) emitting around 1550 nm. This is an important wavelength range for telecommunication and LIDAR applications both requiring narrow linewidth emitters. At room temperature the as-cleaved lasers exhibited a side-mode suppression ratio of 50 dB at an output power of 6 mW. The lasers showed ultra-narrow single-mode spectrum with Lorentzian part of the measured linewidth being ~200 kHz. The results obtained prove nano-imprint lithography suitable for the low-cost manufacturing of high performance single-mode laser diodes.