A simple single-mode fiber loss measurement scheme in the C-band based on fiber loop-cavity ringdown spectroscopy

An extremely sensitive and simple fiber loop-cavity ringdown spectroscopy (FL-CRDS) setup has been designed based on a turn-key nanosecond pulse laser source operating at 1535 nm. The system sensitivity is demonstrated to be approximately 0.01 dB after extracting the characteristic macrobend loss curve of a standard single mode fiber (SMF-28). The experiment demonstrated that the oscillatory behavior in the rapid loss due to the increasing curvature could be seen for single turn bare fibers with radii of curvature from 10–20 mm. Since the wavelength of laser lies in the range of the conventional window, known as C-band, the demonstrated scheme may suggest the use of these techniques in versatile applications where quick results are necessary without the system complexity.