Transmission characteristics of SMS fiber optic sensor structures

Single-Multi-Single Mode Structure Based Band Pass/Stop Fiber Optic Filter With Tunable Bandwidth

“…In Fig. 2(b) 1 we show the influence of axial strain on the transmission bandwidth and on the filter action. We again plot the input power spectrum, showing an insertion loss of 2dB over the range of operating wavelengths.…”

“…Due to their low loss, compact size, high frequency response and ease of insertion in existing optical fiber communication channels, optical fiber filters are preferred over their electronic and integrated optical counterparts. A number of bandpass filter designs based on single-multi-single mode fiber (SMS) structures have been reported in the literature [1]- [3]. A band pass filter action can, in principle, be achieved by matching spot sizes of the fundamental modes of SMF and MMF at the filter central wavelength [1].…”

“…A number of bandpass filter designs based on single-multi-single mode fiber (SMS) structures have been reported in the literature [1]- [3]. A band pass filter action can, in principle, be achieved by matching spot sizes of the fundamental modes of SMF and MMF at the filter central wavelength [1]. At wavelengths near the central wavelength, most of the light will then be coupled to the fundamental mode of the MMF and hence will be coupled out, giving a transmission maximum.…”

Modalmetric interferometer under Fingerprint disturbances: The effect of lateral offset between the single‐mode and multimode fiber splice

“…The fringe number essentially does not change, for the MMF length is kept constant. 11,12 Figure 3 shows the normalized spectral response under fingerprint disturbances for three distinct MMF lengths. Figure 3A,B shows essentially the same peak-to-peak amplitude ($1 dB) response under the same fingerprint disturbance strength for 0.4 and 500 m MMF length, respectively.…”

“…If the fibers and the fusion splice are both perfectly axisymmetric, all energy will primarily excite the fundamental mode LP 01 of the MMF, and some power might go to LP 02 or even LP 03 modes (LP 0m or so-called "even" modes), but, under no circumstance, can SMF excite the broader spectrum of modes as reported by many studies. 12,14,15 Each of these modes travels twice through the MMF at a slightly different phase velocity. At the fusion splice, the distinct modes recombine (with various amounts of relative phase delay) and create a new electric field that is launched back into the SMF.…”