Wide-range temperature dependences of Brillouin scattering properties in polymer optical fiber

Abstract

We investigate the temperature dependences of the Brillouin scattering properties in a perfluorinated graded-index (PFGI-) polymer optical fiber (POF) in a wide temperature range from −160 to 125 °C. The temperature dependences of the Brillouin frequency shift, linewidth, and Stokes power are almost linear at lower temperature down to −160 °C; while they show nonlinear dependences at higher temperature. These behaviors appear to originate from the partial glass transition of the polymer material.

Simplified correlation-domain Brillouin sensor using plastic optical fiber

“…As shown in the inset of Fig. 3(b), the BFS decreased with increasing temperature, with a proportionality constant of -3. of the heated section), which agrees well with a previously reported value [17]. The BFS fluctuations along the nonheated sections showed a standard deviation of approximately ±3.0 MHz, corresponding to strain and temperature measurement errors of around ±0.02% and ±0.9 °C, respectively.…”

“…Then, a partial reflection point can be automatically created at the butt-coupled interface between the POF and the silica SMF (the pigtail of an optical circulator) [15], at which Fresnel-reflected light with a reflectivity of 0.2% (calculated The key to the solution of the second problem is the BFS hopping phenomenon [21], in which the BFS in the POF (BFS: ~2.8 GHz) can be irreversibly upshifted by ~300 MHz only by applying a large strain of >7.3%. Unless cryogenic sensing is the intended application, the BFS "upshift" is preferable because the BFS in a POF decreases with increasing applied strain [16] and temperature [16], [17]). Thus, instead of inserting different fibers around the butt-coupled part, we have only to pull the POF for a length sufficiently longer than half of the spatial resolution (i.e., the width of the 0th correlation peak).…”

“…In the meantime, distributed strain and temperature measurement based on Brillouin scattering in plastic optical fibers (POFs) has become an active area of research [15][16][17][18][19][20]. Owing to their unique features including high flexibility, POFs have potential applications in highly sensitive temperature sensing [16], cryogenic sensing [17], large-strain sensing [18], and sensing with a "memory" function [20].…”

“…Owing to their unique features including high flexibility, POFs have potential applications in highly sensitive temperature sensing [16], cryogenic sensing [17], large-strain sensing [18], and sensing with a "memory" function [20]. Researchers have recently demonstrated (quasi-) distributed Brillouin sensing using POFs based on BOFDA [19] and BOCDR [20].…”

Phonons induced by laser pulses for Brillouin scattering measurements

“…The experimental setup is simpler, and it is possible to choose and change the stimulation point. Furthermore, the Brillouin spectroscopy is a powerful tool for investigating acoustic properties under various measurement conditions, such as temperature, 6,16,17) and pressure, 18) during a phase transition. 19,20) Noncontact stimulation allows one to change these conditions without affecting the transducer used for the induction of phonons.…”