Details
| Original language | English |
|---|---|
| Article number | 38443 |
| Pages (from-to) | 38443-38456 |
| Number of pages | 14 |
| Journal | Optics express |
| Volume | 31 |
| Issue number | 23 |
| Publication status | Published - 31 Oct 2023 |
Abstract
Squeezed light is injected into the dark port of gravitational wave interferometers, in order to reduce the quantum noise. A fraction of the interferometer output light can reach the OPO due to sub-optimal isolation of the squeezing injection path. This backscattered light interacts with squeezed light generation process, introducing additional measurement noise. We present a theoretical description of the noise coupling mechanism and we prove the model with experimental results. We propose a control scheme to achieve a de-amplification of the backscattered light inside the OPO with a consequent reduction of the noise caused by it. The scheme was implemented at the GEO 600 detector and has proven to be crucial in maintaining a good level of quantum noise reduction of the interferometer for high parametric gain of the OPO. In particular, the mitigation of the backscattered light noise helped in reaching 6 dB of quantum noise reduction [Phys. Rev. Lett. 126, 041102 (2021)]. We show that the impact of backscattered-light-induced noise on the squeezing performance is phenomenologically equivalent to increased phase noise of the squeezing angle control. The results discussed in this paper provide a way for a more accurate estimation of the residual phase noise of the squeezed light field. Finally, the knowledge of the backscattered light noise coupling mechanism is a useful tool to inform the design of the squeezing injection path in terms of path stability and optical isolation.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Atomic and Molecular Physics, and Optics
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In: Optics express, Vol. 31, No. 23, 38443, 31.10.2023, p. 38443-38456.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Characterization and evasion of backscattered light in the squeezed-light enhanced gravitational wave interferometer GEO 600
AU - Bergamin, Fabio
AU - Lough, James
AU - Schreiber, Emil
AU - Grote, Hartmut
AU - Mehmet, Moritz
AU - Vahlbruch, Henning
AU - Affeldt, Christoph
AU - Andric, Tomislav
AU - Bisht, Aparna
AU - Brinkmann, Marc
AU - Kringel, Volker
AU - Lück, Harald
AU - Mukund, Nikhil
AU - Nadji, Severin
AU - Sorazu, Borja
AU - Strain, Kenneth
AU - Weinert, Michael
AU - Danzmann, Karsten
N1 - Max-Planck-Gesellschaft; Gottfried Wilhelm Leibniz Universität Hannover; Deutsche Forschungsgemeinschaft (EXC-2123, QuantumFrontiers - 390837967, SFB/Transregio 7); Bundesministerium für Bildung und Forschung; University of Glasgow; Science and Technology Facilities Council (ST/L000946/1).
PY - 2023/10/31
Y1 - 2023/10/31
N2 - Squeezed light is injected into the dark port of gravitational wave interferometers, in order to reduce the quantum noise. A fraction of the interferometer output light can reach the OPO due to sub-optimal isolation of the squeezing injection path. This backscattered light interacts with squeezed light generation process, introducing additional measurement noise. We present a theoretical description of the noise coupling mechanism and we prove the model with experimental results. We propose a control scheme to achieve a de-amplification of the backscattered light inside the OPO with a consequent reduction of the noise caused by it. The scheme was implemented at the GEO 600 detector and has proven to be crucial in maintaining a good level of quantum noise reduction of the interferometer for high parametric gain of the OPO. In particular, the mitigation of the backscattered light noise helped in reaching 6 dB of quantum noise reduction [Phys. Rev. Lett. 126, 041102 (2021)]. We show that the impact of backscattered-light-induced noise on the squeezing performance is phenomenologically equivalent to increased phase noise of the squeezing angle control. The results discussed in this paper provide a way for a more accurate estimation of the residual phase noise of the squeezed light field. Finally, the knowledge of the backscattered light noise coupling mechanism is a useful tool to inform the design of the squeezing injection path in terms of path stability and optical isolation.
AB - Squeezed light is injected into the dark port of gravitational wave interferometers, in order to reduce the quantum noise. A fraction of the interferometer output light can reach the OPO due to sub-optimal isolation of the squeezing injection path. This backscattered light interacts with squeezed light generation process, introducing additional measurement noise. We present a theoretical description of the noise coupling mechanism and we prove the model with experimental results. We propose a control scheme to achieve a de-amplification of the backscattered light inside the OPO with a consequent reduction of the noise caused by it. The scheme was implemented at the GEO 600 detector and has proven to be crucial in maintaining a good level of quantum noise reduction of the interferometer for high parametric gain of the OPO. In particular, the mitigation of the backscattered light noise helped in reaching 6 dB of quantum noise reduction [Phys. Rev. Lett. 126, 041102 (2021)]. We show that the impact of backscattered-light-induced noise on the squeezing performance is phenomenologically equivalent to increased phase noise of the squeezing angle control. The results discussed in this paper provide a way for a more accurate estimation of the residual phase noise of the squeezed light field. Finally, the knowledge of the backscattered light noise coupling mechanism is a useful tool to inform the design of the squeezing injection path in terms of path stability and optical isolation.
UR - http://www.scopus.com/inward/record.url?scp=85177993837&partnerID=8YFLogxK
U2 - 10.1364/OE.497555
DO - 10.1364/OE.497555
M3 - Article
VL - 31
SP - 38443
EP - 38456
JO - Optics express
JF - Optics express
SN - 1094-4087
IS - 23
M1 - 38443
ER -