Ultrasonic sensing using Yb3+/Er3+-codoped distributed feedback fibre grating lasers

Longitudinal Mode Competition in Chirped Grating Distributed Feedback Lasers

Gain competition often inhibits the simultaneous lasing of multiple longitudinal modes in homogeneously broadened laser systems. A stability analysis is developed to demonstrate that the two lowest order degenerate longitudinal modes in an indexcoupled distributed feedback (DFB) laser will lase simultaneously when the index grating is chirped asymmetrically along the axis of the device. This ch...

Grating-free nth order cascaded Raman fibre lasers using highly Ge-doped low loss fibre.

Pumped by a narrow band Nd(3+)-doped fibre laser, a grating-free three-wavelength Raman fibre laser has been demonstrated. More than 1.3W output power at the third Stokes line of 1230 nm, a bandwidth of 1.8nm and a slope efficiency of ~28% was measured. A four-wavelength Raman fibre laser was also demonstrated using a different resonator that consisted of a 4% fibre end reflector, a dielectric ...

Static Fiber-Bragg Grating Strain Sensing Using Frequency-Locked Lasers

Novel and highly sensitive static strain interrogation technique is demonstrated, where the sensing element is a fiberBragg grating (FBG) and the light source is a frequency-locked diode laser. Locking the laser frequency to the center of an absorption line (atomic line of potassium in our experiment) eliminates the slow frequency drift of the laser. The stabilized laser source is used to measu...

Tuneable and switchable dual wavelength lasers using optical fibre Bragg grating external cavities

Brillouin distributed fibre sensing using phase modulated probe

A novel configuration for a Brillouin distributed sensor using a phase modulated probe is presented. It offers the combined advantages of a direct implementation using simple devices and a large immunity to noise, shifting the information from the baseband to a higher frequency, which substantially strengthens the robustness to perturbations, interferences and other optical coherent noises. It ...