An optical fiber Mach-Zehnder interferometer at a wavelength of 1.55 µm has been developed for measurements of high electron density on compact torus (CT) plasmas with a high time resolution of 0.1 µs and high phase resolution of 6.4 × 10-4 rad. To improve density measurement accuracy, the phase noise of the interferometer has been investigated in detail and optimized. In the bench test, the interferometer was calibrated using a piezoelectric ceramic actuator with known stroke. Initial results on CT plasma show that the optical fiber interferometer provides reliable density measurements at two spatial locations and the bulk velocity of plasma can be determined by the method of time of flight.

中文翻译：

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光纤干涉仪用于紧凑环面等离子体的高电子密度测量

已开发出波长为 1.55 µm 的光纤 Mach-Zehnder 干涉仪，用于测量紧凑环面 (CT) 等离子体的高电子密度，具有 0.1 µs 的高时间分辨率和 6.4 × 10-4 rad 的高相位分辨率。为了提高密度测量精度，对干涉仪的相位噪声进行了详细研究和优化。在台架测试中，干涉仪使用已知行程的压电陶瓷驱动器进行校准。CT 等离子体的初步结果表明，光纤干涉仪在两个空间位置提供可靠的密度测量，并且等离子体的体积速度可以通过飞行时间方法确定。