Mode-hop-free tunable high-power distributed feedback laser with adaptable rear facet phase shift section emitting at...

We present a high-power ridge waveguide distributed feedback (DFB) laser with a high-reflective coating and a phase shift section at the rear facet. The phase shift section is realized by means of a micro heater that is placed parallel to the ridge waveguide and the uniform grating. This type of heater section is easy to integrate into existing laser designs and allows adjusting and controlling the spectral behavior of the distributed feedback laser by shifting the rear facet phase condition, which makes it possible to overcome the challenges of mode-hop-free tuning of regular DFB lasers with highly reflective cleaved rear facet. Accordingly, we use the device to quantify rear facet phase conditions where mode hops occur, which are compared to theory with good agreement.