Improvements on Laser Interferometer in Calculable Capacitor at NIM

This paper illustrates the improvements on the laser interferometer in the calculable capacitor at nim, including the fiber coupling optical layout, mechanical drift and aging monitor, and parasitic interference reduction. Using the new fiber coupling, we can more flexible to change the laser source without break the beam layout. And the reduction of parasitic interference is more than one order in amplitude with the benefit of antireflection coatings.