Nonreciprocal vortex isolator via topology-selective stimulated Brillouin scattering
Xinglin Zeng,
Philip Russell,
Christian Wolff ,
Michael Frosz,
Gordon Wong,
Birgit Stiller
Science Advances
8
(42)
eabq6064
(2022)
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Optical nonreciprocity, which breaks the symmetry between forward and backward propagating optical waves, has become vital in photonic systems and enables many key applications. So far, all the existing nonreciprocal systems are implemented for linearly or randomly polarized fundamental modes. Optical vortex modes, with wavefronts that spiral around the central axis of propagation, have been extensively studied over the past decades and offer an additional degree of freedom useful in many applications. Here, we report a light-driven nonreciprocal isolation system for optical vortex modes based on topology-selective stimulated Brillouin scattering (SBS) in chiral photonic crystal fiber. The device can be reconfigured as an amplifier or an isolator by adjusting the frequency of the control signal. The experimental results show vortex isolation of 22 decibels (dB), which is at the state of the art in fundamental mode isolators using SBS. This device may find applications in optical communications, fiber lasers, quantum information processing, and optical tweezers.
Stimulated Brillouin scattering in chiral photonic crystal fiber
Xinglin Zeng,
Wenbin He,
Michael Frosz,
Andreas Geilen,
Paul Roth,
Gordon Wong,
Philip Russell,
Birgit Stiller
Photonics Research
10
(3)
711-718
(2022)
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Stimulated Brillouin scattering (SBS) has many applications; for example, in sensing, microwave photonics, and signal processing. Here, we report the first experimental study of SBS in chiral photonic crystal fiber (PCF), which displays optical activity and robustly maintains circular polarization states against external perturbations. As a result, circularly polarized pump light is cleanly backscattered into a Stokes signal with the orthogonal circular polarization state, as is required by angular momentum conservation. By comparison, untwisted PCF generates a Stokes signal with an unpredictable polarization state, owing to its high sensitivity to external perturbations. We use chiral PCF to realize a circularly polarized continuous-wave Brillouin laser. The results pave the way for a new generation of stable circularly polarized SBS systems with applications in quantum manipulation, optical tweezers, optical gyroscopes, and fiber sensors.
Contact
Research Group Birgit Stiller
Max Planck Institute for the Science of Light Staudtstr. 2 91058 Erlangen, Germany
