VCSEL with increased wavelength dependence on driving current

A method of fabricating a Vertical Cavity Surface Emitting Laser (VCSEL), the method comprising:

• providing an optical resonator;
• and
• electrically contacting the optical resonator for providing an electrical drive current to electrically pump the optical resonator,
• wherein the providing an optical resonator comprises:
• providing a first reflector,
• providing an active region for laser emission,
• providing a second reflector, wherein the active region is arranged between the first reflector and the second reflector,
• providing remaining regions outside the active region, and
• providing a loss layer, wherein the loss layer introduces optical losses at an emission wavelength of the VCSEL and electrical losses, so as to increase wavelength shift of the laser emission when varying the drive current, wherein the optical losses introduced by the loss layer are higher than a sum of optical losses in the remaining regions of the optical resonator, and wherein the electrical losses introduced by the loss layer are higher by a factor of at least 5 than electrical losses in the remaining regions of the optical resonator.