Fig. 1. Experimental setup for gas sensing network based on DWDM and TDM^[40]

Fig. 2. Output spectra via DWDMs and scanned spectra via FP filter in channels 1-4 when HC-PCF is filled with C₂H₂ of 0.1 volume fraction^[40]. (a) Channel 1; (b) channel 2; (c) channel 3; (d) channel 4

Fig. 3. Measured response of sensor to variations of ambient RI^[55]. Reconstructed interferograms for (a) MI formed between R0 and R1 and (c) MI formed between R0 and R2 for different settings of ambient RI; (b) resonant magnitude at ∼3.278 GHz of sensing reflector R1 as a function of ambient RI; (d) resonant magnitude at ∼3.196 GHz of sensing reflector R2 as a function of ambient RI

Fig. 4. Schematic illustration of optical setup of ArFAB as well as direct (label-free) and sandwich (plasmonic labeled) immunoassays over surface of U-FOS probes^[66]

Fig. 5. Eight channel U-FOS probe sensing experiment^[66]. (a) Real-time binding kinetics obtained due to AuNP labels interacting with antigen on U-FOS probes at 280 nm; (b) dose-response curve obtained with ArFAB device for different known concentrations of HIgG [line at the bottom shows the control response from the probes subjected to 0 ng/mL HIgG (n≥3)]

Fig. 6. Distributed hydrogen sensing with stimulated Raman scattering^[71]. (a) Schematic of butt coupling of fiber I with fiber II; (b) schematic of sensing fiber for distributed hydrogen detection over 200-m-long sensing distance, and measured Raman gain trace measured with 18 ns pump pulse

Fig. 7. Experimental setup for distributed RI sensor using tapered fibers in OFDR^[74] (TLS is tunable laser source, FRM is Faraday rotating mirror, PC is polarization controller, BPD is balanced photoelectric detector, DAQ is data acquisition card, FUT is fiber under test, and tapered fiber is immersed in a tank with glycerol solution)

Fig. 8. Distributed RI sensing under different RI^[74]. (a) Spectral shift of the Rayleigh scattering in the tapered fiber as a function of distance at different RI; (b) fitting curve of optical frequency as a function of RI

Fig. 9. Distance-time distribution of RI variation in diffusion of glycerol solution^[73] (glycerol diffused from one side to the other side in sink over time, and RI variation was detected from the one side to the other side of tapered fiber over time)

Fig. 10. Experiment of distributed localization and biosensing^[85]. (a) Schematic diagram of container used in localization experiment of biochemical substances in proposed distributed biosensor; (b) RBS shifts in tapered fiber as a function of distance at different time after adding anti-human IgG to the slot in the container (dotted line marks change of RBS shift at localization point over time); (c) RBS shift of entire tapered region at a time interval of 270 s (position of peak 90.44 mm is location point of slot in container we designed)