POLARIZATION INDEPENDENT PHOTODETECTOR DEVICE AND METHOD OF MAKING SAME

摘要

A photodetector device comprising a photosensitive detector and at least o ne interface between dissimilar media is configured so that a light beam for detection will pass through the interface(s) along a beam axis that is not normal to the interface(s). The deviation from the normal will be such that polarization dependent transmission introduced at the interface(s) wall compensate for inherent polarization dependency of the detector. The deviation may be achieved by inclining the interface(s) relati ve to a predetermined direction along which the light beam will be incident. Where t he photosensitive detector is in a housing with a window through which the ligh t beam enters the housing, the housing can be tilted. In such as case, there are three interfaces, one at the surface of the detector, and one at each surface of the window. Alternatively, the detector surface and/or the window could be tilted. Where a pigtail fibe r is permanently attached to the photodetector device to input the light beam through an interposed lens, the end of the pigtail fiber may be offset laterally from t he lens optical axis so that the beam axis deviates from the normal by such an angle that th e resulting polarization dependent transmission (PDT) substantially corrects for polarization dependent response (PDR) ofthe photosensitive detector. Facets of the pitgtail fiber, the lens, and/or the window may be inclined so that they are not perpendicular t o the axis of the light beam so as to reduce interference and backreflection effects.