Wavelength-interrogated optical sensor for biochemical applications

A novel miniature integrated-optical sensor for versatile multichannel applications is described. Wavelength-modulation techniques using laser diodes (vertical-cavity surface-emitting lasers) are used to interrogate multiple-waveguide sensing regions on a single integrated-optical chip for accurate measurement of effective refractive-index changes at a high data rate. With the experimental miniature sensor system, a resolution of Delta N-PP = 10(-7) (short term, peak to peak) of the effective refractive index was demonstrated. In terms of surface-mass coverage, this resolution corresponds to Delta T-PP = 130 fg/mm(2). (C) 2000 Optical Society of America OCIS codes: 130.2790, 130.6010, 130.6750, 140.3609, 050.2770.