Patent ID: 7697589

Claim:
Apparatus for altering a characteristic of a light-emitting device, the apparatus comprising: a light emitting device having an emission spectrum and defining a fast axis and a slow axis thereof; and a three-dimensional reflective Bragg grating element that is adapted to receive light emitted from the light-emitting device, the emitted light having a first bandwidth, wherein the Bragg grating comprises a plurality of flat Bragg grating planes, wherein the Bragg grating is adapted to redirect only a portion of the received light, the redirected portion having a second bandwidth that is narrower than the first bandwidth, such that the redirected portion is fed back directly into the light-emitting device as a narrow-wavelength seed that causes a narrowing of the emission spectrum of the light-emitting device, and wherein the Bragg grating element is positioned to receive the light emitted from the light emitting device in the absence, between the light emitting device and the Bragg grating element, of any optics that collimates or reduces divergence along either the fast axis or the slow axis of the light emitting device.