Semiconductor light source with electrically tunable emission wavelength

A tunable semiconductor laser comprising:

• an optically active region including at least one type-II heterojunction comprising a first layer with high electron affinity and second layer with low electron affinity such that the energy separation between electrons in the first layer and holes in the second layer is less than semiconductor bandgaps of both the first and the second layers;
• means for pumping electrons in the first layer and holes in the second layer by applying a bias current to the optically active region with a pair of conducting layers disposed on opposite sides of the optically active region;
• and
• means for modulating a transverse electric field in the first layer by changing the bias current that is applied to the optically active region by the pair of conducting layers to thereby modulate wavelengths of laser light emitted in a lasing optical transition between electrons in the first layer and holes in the second layer after a lasing threshold of the laser is achieved.