A multimode interference (MMI) sensor was designed and experimentally demonstrated for simultaneous measurement of curvature and temperature. A typical fiber structure of single-mode fiber – multimode fiber – single-mode fiber (SMS), mounted in a long and thin carbon steel sheet, and then coated with polydimethylsiloxane (PDMS) was manufactured and tested in curvature and temperature. Bending laboratory results showed that the proffered sensor has a curvature sensitivity of -0.9835 dB/m<sup>-1</sup> over a range from 0 m<sup>-1</sup> to 1.3652 m<sup>-1</sup> , measurements were taken by keeping a constant temperature of 30°C. The laboratory temperature response was -119 pm/°C at a temperature range from 30°C to 60°C, showing an improvement in temperature response, temperature measurements were taken by keeping a constant bending of 0 m<sup>-1</sup> . The results show that PDMS coatings are a good way to improve multimode interferometer sensitivity during temperature measurement while keeping a good curvature measuring response, moreover the device shows a linear response within the curvature and temperature ranges. Another advantage of the PDMS coating is that it makes the sensor insensitive to refractive index changes, it gives the sensor robustness and protection against dust.
We report the fabrication of a saturable absorber made of a novel polymer SU8 doped with Single Wall Carbon
Nanotubes (SWCNTs). A passive mode-locked ring cavity fiber laser was built with a 100 μm thick SU8/SWCNT film
inserted between two FC/APC connectors. Self-starting passively mode-locked lasing operation was observed at 1572.04
nm, with a FWHM of 3.26 nm. The autocorrelation trace was 1.536 ps corresponding to a pulse-width of 871 fs. The
time-bandwidth product was 0.344, which is close enough to transform-limited sech squared pulses. The repetition rate
was 21.27 MHz, and a maximum average output power of 1 mW was also measured.