Tunable laser with active material on at least one end for monitoring performance

A laser comprising:

• at least one gain region including a gain configured to generate light;
• a first optical reflector at one end of the at least one gain region, the first optical reflector having at least one reflection peak in a gain bandwidth of the at least one gain region;
• a second optical reflector having a plurality of reflection peaks at another end of the at least one gain region, the first optical reflector and the second optical reflector forming a cavity including the at least one gain region therein, the cavity having a plurality of cavity modes spaced apart from each other,
• at least one optically active region configured to generate an electric signal indicative of light transmitted from the at least one gain region in a first time period, and to amplify or attenuate the light transmitted from the at least one gain region in a second time period different from the first time period;
• at least one temperature controller configured to adjust the temperature of at least said second optical reflector;
• and
• electronics configured to align a cavity mode of the plurality of cavity modes with one or both of a reflection peak of the first optical reflector and a reflection peak of the second optical reflector.