Laser Structure

A structure comprising:

• a substrate comprising a front facet, a back facet, and a waveguide formed on and/or in the substrate, the waveguide comprising a first arm extending between the front facet and the back facet of the substrate and a second arm extending between the front facet and a back facet of the substrate, with at least a section of the first arm and a section of the second arm disposed in spaced side-by-side relation to each other, wherein:
• the first arm includes a distributed feedback (DFB) laser or a semiconductor optical amplifier (SOA);
• the second arm includes a SOA;
• at, proximate to, or adjacent the front facet, first ends of the first and second arms are spaced from each other by a first distance and an anti-reflective coating is disposed over at least the first ends of the first and second arms;
• and
• at, proximate to, or adjacent the back facet, second ends of the first and second arms are spaced from each other by a second distance.