Waveguide sensor configuration

Fig. 6 a General waveguide sensor configuration b typical sensorgram... 

Waveguide Sensors Using Low Index Substrates Reverse Waveguide Configuration... 

Fig. 1 Various ring resonator sensor configurations, (a) Microsphere, (b) Silicon-on-insulator planar ring resonator, (c) Slot waveguide ring resonator, (d) Planar disc ring resonator, (e) Glass planar ring array, (f) Microtoroid, (g) Microknot, (h) Opto-fluidic ring resonator (OFRR) and the inset is the SEM image of the OFRR cross-section. Reprinted with permissions from refs [13, 28, 30, 32, 50, 53, 70, 86]...

Fig. 9.11 The calculated response of a 1.5 mm long silicon PWEF sensor in a Mach Zehnder interferometer configuration, as a film of final thickness d 2 nm and index n 1.5 grows on the waveguide surface. The normalized fractional surface coverage is also shown...

As mentioned in Sect. 15.2, sometimes a 4th thin layer (M) of metal or die is incorporated between the substrate and waveguide film to decrease the radiation loss into the substrate of the substrate radiation modes. These modes are referred to as leaky modes and the obtained structure is the MCLW. This configuration is also broadly used in evanescent wave sensor systems. 

For refractive-index-type sensors, the waveguide is intrinsically the sensing element, and then chemical processes are measured with the variations of the refractive index, n, of guided modes. The majority of the various sensor types and published configurations make use of grating couplers (Fig. 10a) [83,84], resonant mirrors (Fig. 10b) [52,86-89] or interferometric sensors (Fig. 11) as... 

Fig. 14 Standard configuration of hollow-based sensors. Flow is injected from a reservoir to the microchannel that also forms the hollow waveguide. Light interacts with the flow after crossing the input membrane and the signal is read after the output membrane...

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