Whispering gallery mode (WGM) resonators with high optical quality factor (Q) are sensitive to environment changes and are used in various sensing applications. We have developed a high-precision temperature sensor using a compactly packaged lithium niobate WGM resonator. This sensor offers a sensitivity of 34.38 pm °C−1 and a high resolution of up to °C. It is portable with high Q, making it suitable for using outside the laboratory. The device is also resilient to changes in humidity, enhancing its practicality.
Linear and nonlinear coupling of light in twin-resonators with Kerr nonlinearity
Arghadeep Pal,
Alekhya Ghosh,
Shuangyou Zhang,
Lewis Hill,
Haochen Yan,
Hao Zhang,
Toby Bi,
Abdullah Alabbadi,
Pascal Del'Haye
Photonics Research
12
(11)
2733-2740
(2024)
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Nonlinear effects in microresonators are efficient building blocks for all-optical computing and telecom systems. With the latest advances in microfabrication, coupled microresonators are used in a rapidly growing number of applications. In this work, we investigate the coupling between twin-resonators in the presence of Kerr nonlinearity. We use an experimental setup with controllable coupling between two high-Q resonators and discuss the effects caused by the simultaneous presence of linear and nonlinear coupling between the optical fields. Linear-coupling-induced mode splitting is observed at low input powers, with the controllable coupling leading to a tunable mode splitting. At high input powers, the hybridized resonances show spontaneous symmetry breaking (SSB) effects, in which the optical power is unevenly distributed between the resonators. Our experimental results are supported by a detailed theoretical model of nonlinear twin-resonators. With the recent interest in coupled resonator systems for neuromorphic computing, quantum systems, and optical frequency comb generation, our work provides important insights into the behavior of these systems at high circulating powers.
Frequency Comb Enhancement via the Self-Crystallization of Vectorial Cavity Solitons
Graeme Neil Campbell,
Lewis Hill,
Pascal Del'Haye,
Gian-Luca Oppo
Optics Express
32
37691-37702
(2024)
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Long-range interactions between dark vectorial temporal cavity solitons are induced by the formation of patterns via spontaneous symmetry breaking of orthogonally polarized fields in ring resonators. Turing patterns of alternating polarizations form between adjacent solitons, pushing them apart so that a random distribution of solitons along the cavity length spontaneously reaches equal equilibrium distances, the soliton crystal, without any mode crossing or external modulation. Enhancement of the frequency comb is achieved through the spontaneous formation of regularly spaced soliton crystals, ‘self-crystallization,’ with greater power and spacing of the spectral lines for increasing soliton numbers. Partial self-crystallization is also achievable in long cavities, allowing one to build crystal sections with controllable numbers of cavity solitons separated by intervals of pattern solutions of, again, controllable length.
Controlled light distribution with coupled microresonator chains via Kerr symmetry breaking
Alekhya Ghosh,
Arghadeep Pal,
Lewis Hill,
Graeme N Campbell,
Toby Bi,
Yaojing Zhang,
Abdullah Alabbadi,
Shuangyou Zhang,
Gian-Luca Oppo, et al.
Photonics Research
12
2376-2389
(2024)
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Within optical microresonators, the Kerr interaction of photons can lead to symmetry breaking of optical modes. In a ring resonator, this leads to the interesting effect that light preferably circulates in one direction or in one polarization state. Applications of this effect range from chip-integrated optical diodes to nonlinear polarization controllers and optical gyroscopes. In this work, we study Kerr-nonlinearity-induced symmetry breaking of light states in coupled resonator optical waveguides (CROWs). We discover, to our knowledge, a new type of controllable symmetry breaking that leads to emerging patterns of dark and bright resonators within the chains. Beyond stationary symmetry broken states, we observe Kerr-effect-induced homogeneous periodic oscillations, switching, and chaotic fluctuations of circulating powers in the resonators. Our findings are of interest for controlled multiplexing of light in photonic integrated circuits, neuromorphic computing, topological photonics, and soliton frequency combs in coupled resonators.
On-the-fly precision spectroscopy with a dual-modulated tunable diode laser
and Hz-level referencing to a cavity
Shuangyou Zhang,
Toby Bi,
Pascal Del'Haye
Advanced Photonics
6
046003
(2024)
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Advances in high-resolution laser spectroscopy have enabled many scientific breakthroughs in physics, chemistry, biology and astronomy. Optical frequency combs have pushed measurement limits with ultrahigh-frequency accuracy and fast-measurement speed while tunable diode laser spectroscopy is used in scenarios that require high power and continuous spectral coverage. Despite these advantages of tunable diode laser spectroscopy, it is challenging to precisely determine the instantaneous frequency of the laser because of fluctuations in the scan speed. Here we demonstrate a simple spectroscopy scheme with a frequency modulated diode laser that references the diode laser on-the-fly to a fiber cavity with sub-15 Hz frequency precision over an 11-THz range at a measurement speed of 1 THz/s. This is an improvement of more than two orders of magnitude compared to existing diode laser spectroscopy methods. Our scheme provides precise frequency calibration markers while simultaneously tracking the instantaneous scan speed of the laser. We demonstrate several applications, including dispersion measurement of an ultra-high-Q microresonator and spectroscopy of an HF gas cell, which can be used for absolute frequency referencing of the tunable diode laser. The simplicity, robustness and low costs of this spectroscopy scheme could prove extremely valuable for out-of-the-lab applications like LIDAR, gas spectroscopy and environmental monitoring.
Phase Symmetry Breaking of Counterpropagating Light in Microresonators for Switches and Logic Gates
Alekhya Ghosh,
Arghadeep Pal,
Shuangyou Zhang,
Lewis Hill,
Toby Bi,
Pascal Del'Haye
The rapidly growing field of integrated photonics is enabling a large number of novel devices for optical data processing, neuromorphic computing and circuits for quantum photonics. While many photonic devices are based on linear optics, nonlinear responses at low threshold power are of high interest for optical switching and computing. In the case of counterpropagating light, nonlinear interactions can be utilized for chip-based isolators and logic gates. In our work we find a symmetry breaking of the phases of counterpropagating light waves in high-Q ring resonators. This abrupt change in the phases can be used for optical switches and logic gates. In addition to our experimental results, we provide theoretical models that describe the phase symmetry breaking of counterpropagating light in ring resonators.
Symmetry broken vectorial Kerr frequency combs from Fabry-Pérot resonators
Lewis Hill,
Eva-Maria Hirmer,
Graeme Campbell,
Toby Bi,
Alekhya Ghosh,
Pascal Del'Haye,
Gian-Luca Oppo
Communications Physics
7
82
(2024)
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Spontaneous symmetry breaking of a pair of vector temporal cavity solitons has been established as a paradigm to modulate optical frequency combs, and finds many applications in metrology, frequency standards, communications, and photonic devices. While this phenomenon has successfully been observed in Kerr ring resonators, the counterpart exploiting linear Fabry-Pérot cavities is still unexplored. Here, we consider field polarization properties and describe a vector comb generation through the spontaneous symmetry breaking of temporal cavity solitons within coherently driven, passive, Fabry-Pérot cavities with Kerr nonlinearity. Global coupling effects due to the interactions of counter-propagating light restrict the maximum number of soliton pairs within the cavity - even down to a single soliton pair - and force long range polarization conformity in trains of vector solitons.
Real-time imaging of standing-wave patterns in microresonators
Haochen Yan,
Alekhya Ghosh,
Arghadeep Pal,
Hao Zhang,
Toby Bi,
George N. Ghalanos,
Shuangyou Zhang,
Lewis Hill,
Yaojing Zhang, et al.
Proceedings of the National Academy of Sciences of the United States of America
121
e2313981121
(2024)
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Real-time characterization of microresonator dynamics is important for many applications. In particular, it is critical for near-field sensing and understanding light–matter interactions. Here, we report camera-facilitated imaging and analysis of standing wave patterns in optical ring resonators. The standing wave pattern is generated through bidirectional pumping of a microresonator, and the scattered light from the microresonator is collected by a short-wave infrared (SWIR) camera. The recorded scattering patterns are wavelength dependent, and the scattered intensity exhibits a linear relation with the circulating power within the microresonator. By modulating the relative phase between the two pump waves, we can control the generated standing waves’ movements and characterize the resonator with the SWIR camera. The visualized standing wave enables subwavelength distance measurements of scattering targets with nanometer-level accuracy. This work opens broad avenues for applications in on-chip near-field (bio)sensing, real-time characterization of photonic integrated circuits, and backscattering control in telecom systems.<br>
Contact
Research GroupPascal Del'Haye
Max Planck Institute for the Science of Light Staudtstr. 2 91058 Erlangen, Germany
