52 research outputs found
GW26-e1576 The Association between Frequent Premature Ventricular Contractions and the Left Ventricular Function of Late Pregnant Women
Automated turnkey microcomb for low-noise microwave synthesis
Microresonator-based optical frequency comb (microcomb) has the potential to
revolutionize the accuracy of frequency synthesizer in radar and communication
applications. However, fundamental limit exists for low noise microcomb
generation, especially in low size, weight, power and cost (SWaP-C) package.
Here we resolve this limit, by the demonstration of an automated turnkey
microcomb, operating close to its low quantum-limited phase noise, within a
compact setup size of 85 mm * 90 mm * 25 mm. High quality factor fiber
Fabry-Perot resonator (FFPR), with Q up to 4.0 * 10^9, is the key for both low
quantum noise and pump noise limit, in the diode-pump case in a self-injection
locking scheme. Low phase noise of -80 and -105 dBc/Hz at 100 Hz, -106 and -125
dBc/Hz at 1 kHz, -133 and -148 dBc/Hz at 10 kHz is achieved at 10.1 GHz and 1.7
GHz repetition frequencies, respectively. With the simultaneous automated
turnkey, low-noise and direct-diode-pump capability, our microcomb is ready to
be used as a low-noise frequency synthesizer with low SWaP-C and thus field
deployability
Synthesized spatiotemporal mode-locking and photonic flywheel in multimode mesoresonators
Dissipative Kerr soliton (DKS) frequency combs—also known as microcombs—have arguably created a new field in cavity nonlinear photonics, with a strong cross-fertilization between theoretical, experimental, and technological research. Spatiotemporal mode-locking (STML) not only adds new degrees of freedom to ultrafast laser technology, but also provides new insights for implementing analogue computers and heuristic optimizers with photonics. Here, we combine the principles of DKS and STML to demonstrate the STML DKS by developing an unexplored ultrahigh-quality-factor Fabry–Pérot (FP) mesoresonator based on graded index multimode fiber (GRIN-MMF). Complementing the two-step pumping scheme with a cavity stress tuning method, we can selectively excite either the eigenmode DKS or the STML DKS. Furthermore, we demonstrate an ultralow noise microcomb that enhances the photonic flywheel performance in both the fundamental comb linewidth and DKS timing jitter. The demonstrated fundamental comb linewidth of 400 mHz and DKS timing jitter of 500 attosecond (averaging times up to 25 μs) represent improvements of 25× and 2.5×, respectively, from the state-of-the-art. Our results show the potential of GRIN-MMF FP mesoresonators as an ideal testbed for high-dimensional nonlinear cavity dynamics and photonic flywheel with ultrahigh coherence and ultralow timing jitter.
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