Patent ID: 8687667

Claim:
Laser system comprising: at least one externally stabilizable semiconductor laser, from a laser active zone of which a laser radiation field can be coupled out, and a feedback element, disposed externally in the laser radiation field, which couples out, from the laser radiation field, a feedback radiation field having a defined wavelength and bandwidth, and coupling back the same into the active laser zone for determining a wavelength and bandwidth of the laser radiation field, the feedback element being a resonant waveguide grating which reflects back a portion of the laser radiation field lying within an angular acceptance range, the feedback element being a resonant waveguide grating having multiple periodicity, the resonant waveguide grating has an angular acceptance range of greater than Â±2Â°, the resonant waveguide grating being composed of at least three waveguide layers: a topmost waveguide layer having a high index of refraction, a waveguide layer therebeneath having a low index of refraction, and a waveguide layer, situated opposite from the topmost waveguide layer, having a high index of refraction.