Patent ID: 7504665
Filing Date: 2009-03-17
Classification: G01N,H01L,H01S

Abstract:
1. A device comprising: a semiconductor substrate arranged for emitting light for incidence on an element and also responsive to light received from said element; and means for monitoring a characteristic of the device which varies in dependence upon said light received from said element; wherein the device includes a resonant cavity light emitting element integrated as part of said substrate for emitting light of a first wavelength range, comprising a reflector through which light is emitted, the reflector comprising a plurality of alternating layers of high and low refractive index material, a layer of absorbing material being incorporated into or associated with said reflector, said absorbing layer realized from a bandgap material that absorbs light of a second wavelength range different from said first wavelength range while not absorbing light of said first wavelength range.