Greater than 10/sup 6/ optical isolation in integrated optoelectronic fluorescence sensor

Integrated optoelectronic sensors hold much potential for bio-medical applications. Our work focuses on the use of semiconductor lasers, photodetectors and filters to create a monolithically integrated near-infrared fluorescence sensor. Previous research has found that the close integration of these components results in large laser background levels from spontaneous emission emitted from the side of the laser and limits sensor sensitivity. This work presents an improved optical blocking structure between the laser and photodetector which results in greater than 10/sup 6/ optical isolation. This level of isolation will allow for sensitive fluorescence detection and shows that optoelectronic components can be successfully integrated for such purposes.