<title>Miniature integrated optical sensors</title>

Embossable grating couplers for planar evanescent wave sensors

“…The said effects bring about the change of effective refractive in− dexes of modes propagating in the structure. The changes of effective refractive indexes can be measured by the applica− tion of the interferometers of Mach−Zehnder [4,5], Young [6,7] and with a polarimeter [1,[8][9][10] or grating couplers [3,[11][12][13][14][15][16][17][18]. In chemical and biochemical measurements, surface plasmon resonance sensors are also applied [19,20].…”

“…Grating couplers as sensor ele− ments were for the first time applied by the research team led by Lukosz [11,12]. The application of grating couplers for sensor application has been also intensively investigated by Kuntz et al [13][14][15], and by Vörös, Szendrö, and Horváth [16,17]. Commercial measurement systems based on input grating couplers are already available [18].…”

<title>Miniature integrated optical refractometer chip</title>

“…If the degree of freedom representing the measuring variable is integrated into the chip, problems and adjustment efforts related with external optics and other auxiliary equipment can be avoided [1, 2,3]. High sensitivities can be achieved by making use of the resonance condition for waveguide grating couplers [4,5].…”

“…If the test liquid is used as the cover medium of such a waveguide, the position of this integrated optical (10) light pointer represents a convenient on-chip measuring variable and provides the possibility of realizing miniature low-cost refractometers. First experimental results were reported in [3] for a Ta205 waveguide with exponential thickness gradient. This paper reports on the performance of a Ti02 waveguide chip with a linear slope in film thickness, offering an increased sensitivity due to the higher index of the film and the shallower slope of the thickness taper.…”

“…In the waveguides used for the measurements, only the TE0 and TM0 mode could propagate. The thickness and the refractive index of the waveguiding film at the actual position Yb can be calculated from the resonance angles based on the formulas given in [3]. By repeating this procedure at different waveguide positions y and fitting the evaluated data by a linear model function, the slopes of the waveguide's thickness and index variations are calculated.…”