Microfiber-based devices: Current sensor and tunable laser

Microfibers and its knot resonator structure are fabricated using a flame-brushing technique for current sensor and tunable Erbium-doped fiber laser (EDFL) applications. A compact current sensor using a microfiber knot resonator (MKR) is demonstrated based on idea of measuring the thermally induced resonant wavelength shift as a result of heat produced due to the flow of electric current over a copper rod. A tunable fiber laser is also demonstrated using a MKR structure made by a highly doped Erbium fiber. A stable laser output is achieved at 1533nm region with a signal to noise ratio (SNR) of 15dB. With the assistance of a copper wire touching the circumference of the ring, the peak wavelength of the laser can be tuned from 1533.3nm to 1533.9nm as the loading current is increased from 0 to 1.0 A.