Duration: 8 months
Nowadays, the most frequently used high performance optical reference for laser frequency stabilization is an optical cavity with ultralow loss reflective coatings which is then placed in a vacuum chamber to minimise variations in refractive index which would lead to unpredictable and therefore undesirable Optical Path Length (OPL) changes. The optical cavity, contained within the vacuum chamber, must also be isolated from vibrations and with the additional complexity of a temperature stabilisation system involving complex and costly technologies. This, nevertheless, represents a powerful tool for laser linewidth narrowing and/or laser frequency noise characterization at ultralow level (mHz-level linewidth and < 10^-3 Hz²/Hz frequency noise floor).
However, these technologies are not optimum for space applications regarding their size and weight, complexity, and sensitivity to environmental variations. While the volume and mass of these systems has been significantly reduced in the past years due to dedicated efforts funded by ESA, the vibrational and thermal operational complexities still remain.
SILENTSYS developed and commercialize an ultralow noise optical frequency discriminator (OFD) that can reach high performances in a compact form factor thanks to full optical fibre scheme. This technology still limits the ability to miniaturise the optical interferometer.
Through this study, we aim to investigate the shift to a new technology: optical fibre micro-coils and integrated photonic circuits. Thanks to those technologies, we could achieve optimum compactness and insulation for on-board space applications but it impacts the temperature stabilisation of the system as well as its vibro-acoustic isolation since, in the current state of the art, no solution provides sufficient insulation to maintain optimum stabilisation performances.
