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

A report is presented on the use of nanoimprint lithography for the fabrication of InP-based laterally-coupled ridge waveguide distributed feedback laser (DFB) diodes emitting around 1550 nm. At room temperature the uncoated lasers exhibited a sidemode suppression ratio of 50 dB at an output power of 6 mW. The lasers showed extremely pure singlemode spectrum with the Lorentzian part of the measured linewidth being ∼200 kHz. The results prove that nanoimprint lithography is suitable for the low-cost manufacturing of high performance singlemode laser diodes.