S. Schediwy

High-precision optical-frequency dissemination on branching optical-fiber networks

We present a technique for the simultaneous dissemination of high-precision optical-frequency signals to multiple independent remote sites on a branching optical-fiber network. The technique corrects optical-fiber length fluctuations at the output of the link, rather than at the input as is conventional. As the transmitted optical signal remains unaltered until it reaches the remote site, it can be transmitted simultaneously to multiple remote sites on an arbitrarily complex branching network. This technique maintains the same servo-loop bandwidth limit as in conventional techniques and is compatible with active telecommunication links.

ACIGA's high optical power test facility

Advanced laser interferometer detectors utilizing more than 100 W of laser power and with ~106 W circulating laser power present many technological problems. The Australian Consortium for Interferometric Gravitational Astronomy (ACIGA) is developing a high power research facility in Gingin, north of Perth, Western Australia, which will test techniques for the next generation interferometers. In particular it will test thermal lensing compensation and control strategies for optical cavities in which optical spring effects and parametric instabilities may present major difficulties.

Gingin High Optical Power Test Facility

The Australian Consortium for Gravitational Wave Astronomy (ACIGA) in collaboration with LIGO is developing a high optical power research facility at the AIGO site, Gingin, Western Australia. Research at the facility will provide solutions to the problems that advanced gravitational wave detectors will encounter with extremely high optical power. The problems include thermal lensing and parametric instabilities. This article will present the status of the facility and the plan for the future experiments.

Status of the Australian Consortium for Interferometric Gravitational Astronomy

We report the status of research and development being undertaken by the members of the Australian Consortium for Interferometric Gravitational Astronomy.

An experiment to investigate optical spring parametric instability

Recently it has been shown that parametric instabilities may significantly affect the performance of high power signal recycling gravitational wave interferometers such as the planned Advanced LIGO. We propose an experiment utilizing the optical spring effect to determine the likelihood of parametric instability. A mechanical resonator has been designed to maximize parametric instability with R0 = 500. We show that cold damping will reduce the quality factor to ~1000 while the rigidity is increased to ~1500 N m−1.

Square Kilometre Array: The radio telescope of the XXI century

The Square Kilometre Array (SKA) will be the world’s largest and most sensitive radio telescope. It will address fundamental unanswered questions about our Universe including how the first stars and galaxies formed after the Big Bang, how dark energy is accelerating the expansion of theUniverse, the role of magnetism in the cosmos, the nature of gravity, and the search for life beyond Earth. This project envisages the construction of 133 15-m antennas in South Africa and 131072 log-periodic antennas in Australia, together with the associated infrastructure in the two desert sites. In addition, the SKA is an exemplar Big Data project, with data rates of over 10 Tbps being transported from the telescope to HPC/HTC facilities.

Stabilized microwave-frequency transfer using optical phase sensing and actuation

We present a stabilized microwave-frequency transfer technique that is based on optical phase sensing and optical phase actuation. This technique shares several attributes with optical-frequency transfer and, therefore, exhibits several advantages over other microwave-frequency transfer techniques. We demonstrated the stabilized transfer of an 8000 MHz microwave-frequency signal over a 166 km metropolitan optical fiber network, achieving a fractional frequency stability of 6.8×10-14  Hz/Hz at 1 s integration and 5.0×10-16  Hz/Hz at 1.6×104  s. This technique is being considered for use on the Square Kilometre Array SKA1-mid radio telescope.

Technology developments for ACIGA high power test facility for advanced interferometry

The High Optical Power Test Facility for Advanced Interferometry has been built by the Australian Consortium for Interferometric Gravitational Astronomy north of Perth in Western Australia. An 80 m suspended cavity has been prepared in collaboration with LIGO, where a set of experiments to test suspension control and thermal compensation will soon take place. Future experiments will investigate radiation pressure instabilities and optical spring effects in a high power optical cavity with ~200 kW circulating power. The facility combines research and development undertaken by all consortium members, whose latest results are presented.

Microwave frequency transfer with optical stabilisation

In this paper we present a novel frequency dissemination technique which uses an all-optical interferometer to sense length fluctuations with high precision, and then utilises this information to simultaneously stabilise a transmitted optical and signal and a microwave signal.

High Q factor bonding using natural resin for reduced thermal noise of test masses

We show that a low acoustic loss resin enables composite mechanical structures to be bonded with minimal Q degradation. The resin is excreted from the Australian native grass tree Xanthorrhoea. This resin has traditionally been used as an adhesive by the Australian Aborigines. It is shown that the Q factor of the resin is greater than 300 for the 5180Hz resonance, which allows a high Q factor niobium resonator to be constructed with bonded mirrors while maintaining a Q of ∼106.