Improvement of infrared temporal profile measurement system for SG-III prototype laser facility

In order to improve the stability, reliability and economy of temporal profile measurement system on SG-III prototype laser facility, the old measurement system of temporal profile was reconstructed. The new system was composed of power sampling, fiber-optic delays, multiplexing coupler, optical-to-telectrical conversion and data processing. The fiber sampler with near field beam coupling was adopted, a commercial, high-speed, four-channel digitizer was used, samples of 16 beams were taken with fiber-optic pickoffs, separated in time with appropriate fiber-optic delays and presented to a high-speed fiber-optic photoreceiver, which converted the samples to electrical signals for the digitizer. Intensity and time multiplexing were used to cover the required dynamic range, making the cost per sample competitive with alternative approaches.