Abstract: An optical device comprises a light source, an intensity control element (adjustable between an on-state and an off-state), an optical channel, and an optical component. The light source supplies an optical pulse to the intensity control element, which modulates an intensity of the received pulse and to provides the modulated pulse to the channel. The intensity of the modulated pulse is higher when the intensity control element is in the on-state than in the off-state. The optical component receives the modulated pulse from the channel. The optical intensity modulator is configured such that at least a portion of the pulse is modulated in the on-state, the leading edge of said portion exits the intensity modulator at a first time, and the intensity modulator is in the off-state at a second time which is twice the propagation time measured from to the first time.

Abstract: Provided is a sensor and method for weld defect detection. The sensor includes several piezoelectric elements which form a matrix arranged on a flexible substrate. Each piezoelectric element is covered with a damping block and surrounded by sound absorbing material, within a flexible protective film. The sensor is simple, highly adaptable and high detection efficiency, which is especially suitable for the quick in-service inspection of long distance welds in large equipment, it has high degree of automation.

Abstract: Provided is a sensor and method for weld defect detection. The sensor includes several piezoelectric elements which form a matrix arranged on a flexible substrate. Each piezoelectric element is covered with a damping block and surrounded by sound absorbing material, and packaged within a flexible protective film. The sensor is simple, highly adaptable and high detection efficiency, which is especially suitable for the quick in-service inspection of long distance welds in large equipment, it has high degree of automation.