Patent ID: 7386207
Filing Date: 2008-06-10
Classification: G02B,H01L,Y02E,Y02P

Abstract:
1. An integrated optical waveguide having an in-line light sensor integrally formed therewith, comprising: a first part of the waveguide leading to a photodiode portion thereof; a second part of the waveguide leading away from the photodiode portion, a material from which said first and second parts of the waveguide are formed having an energy band gap a magnitude of which corresponds to absorption of photons of a first wavelength, the photodiode portion comprising one or more regions of light absorbing material within the waveguide arranged to absorb a minor proportion of light of one or more selected wavelengths transmitted along the waveguide such that a major proportion of the light passes through to the second part of the waveguide to thereby generate free charge carriers within the photodiode portion of the waveguide, the photodiode portion having a modification that introduces deep band gap levels therein so as to provide at least partial absorption of photons of a selected wavelength or wavelength band greater than said first wavelength; detecting means for detecting the presence of said free charge carriers; and in which the material of the waveguide and/or the dimensions thereof are selected so as to provide similar confinement factors for both the TE and TM modes whereby the detection of light thereby is substantially polarization independent.