Analytical discussion of semiconductor lasers for gravitational-wave detection

The primary objective of the Deci-hertz Interferometer Gravitational Wave Observatory (DECIGO) mission is to detect and observe black holes' and galactic binaries' gravitational waves (GWs), at frequencies ranging from 10-2 to 101 Hz. This low-frequency range is inaccessible to ground-based interferometers, due to unshieldable background noise, and the fact that ground-based interferometers are limited to a few kilometers in length. Our research is focused on efforts to stabilize semiconductor-, Nd:YAG- and fiber- lasers, for use as GW detectors' optical sources. In present-day- and future detectors' frequency- and phase-noise may place certain limitations on sensitivity and stability. Our goals (shared with scientists around the world) are; first, to design robust experiments that will measure a variety of noises (random-walk FM, flicker-FM, white FM, flicker PM and white PM), in order to verify existing models, and second, to find ways to reduce sensitivity to spurious noise. Current models predict a variety of frequency- and phase-dependent noise slopes, but, a conclusive distinction between noise-models can only be made when the exact points at which the noises occurred are known. In order to increase the sensitivity of the experiment, the laser frequency is stabilized to an atomic-frequency-reference by a feedback-loop control system.