http://arxiv.org/abs/1709.06515
LISA is a space-based laser interferometer that will detect gravitational waves by using three satellites in a triangular constellation with laser links in-between. Each satellite houses two optical benches that are articulated by moving optical subassemblies for compensating the breathing angle in the constellation. An optical phase reference distribution system, also known as backlink, is required to form an optical path for bi-directional light exchange between the intra-satellite benches.
In this article we present potential backlink candidates with a target non-reciprocity of at most $2\pi\,\mathrm{\mu rad/\sqrt{Hz}}$, equivalent to $1\,\mathrm{pm/\sqrt{Hz}}$ for an assumed wavelength of $1064\,$nm. The candidates are a previously demonstrated direct fiber, a frequency separated fiber and a steered free beam backlink. They are all to be compared in a single experimental set-up. We show the results of an IfoCAD simulation of the interferometer which includes the component alignment together with ray tracing and a ghost beam analysis, a power budget calculation and a noise estimation. First experimental results of a free beam laser link between two optical set-ups that are rotating by $\pm 1\,^\circ$ relative to each other are demonstrated, achieving closed-loop operation. The experiment demonstrated the readiness and analyzed the thermal behavior of our laboratory infrastructure.
K. Isleif, L. Bischof, S. Ast, et. al.
Wed, 20 Sep 17
44/57
Comments: 29 pages, 18 figures, submitted to Classical Quantum Gravity