LIGO Document T1400501-v1
- It has been demonstrated that polarization-maintaining single mode optical fiber can be used to transport frequency-stable light. It is desired to transport stable light to other labs in West Bridge to serve as a frequency reference for various experiments investigating different sources of noise in gravitational-wave detectors. Stable light has been obtained from ultra-stable Fabry-P ́erot cavities. We have mode matched stable light into the fiber and are using a double-pass acousto-optic modulator (AOM) configuration to cancel fiber phase noise. We use a beamsplitter to interfere the stable light and double passed light onto a photodiode, which is connected to a phase-locked loop (PLL) to measure the beat frequency. From there, we analyze the noise in the system by measuring the power spectral density of the PLL control signal with a spectrum analyzer. We measured the expected dominant sources of noise in the set up by using a similar PLL set-up and found a large source of noise coming from the AOM driver. This was replaced with a low noise driver and we will proceed to transport the fiber to another lab once we identify and suppress any other possible noise sources.
DCC Version 3.4.0, contact
Document Database Administrators