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Chaotic semiconductor lasers have been widely investigated for high-speed random bit generation, which is applied for the generation of cryptographic keys for classical and quantum cryptography systems. Here, we propose and demonstrate a self-chaotic microlaser with enhanced chaotic bandwidth for high-speed random bit generation. By designing tri-mode interaction in a deformed square microcavity laser, we realize a self-chaotic laser caused by two-mode internal interaction, and achieve an enhanced chaotic standard bandwidth due to the photon–photon resonance effect by introducing the third mode. Moreover, 500 Gb/s random bit generation is realized and the randomness is verified by the NIST SP 800-22 statistics test. Our demonstration promises the applications of microlasers in secure communication, chaos radar, and optical reservoir computing, and also provides a platform for the investigations of multimode nonlinear laser dynamics.

Abstract Background This cross-sectional study aims to evaluate the association of periodontal conditions and oral hygiene habits in the Chinese patients with an aortic aneurysm (AA). Methods A questionnaire and periodontal examinations were carried out in the AA patients and non-AA volunteers recruited from the Center for Cardiac Surgery, Beijing Anzhen Hospital, Capital Medical University between August 2011 and June 2016. General information (e.g., height and weight), history of systemic diseases, and oral hygiene habits (e.g., brushing methods and regular oral examinations) were collected in the self-reported survey. Periodontal examinations, such as plaque index and bleeding index, were conducted in all the subjects. The correlation between periodontal indices and AA was further explored using univariate and multivariate analyses. Results Our analyses revealed that 87.6% of AA patients have chronic periodontitis, which is significantly higher than that of the non-AA patients (55.8%). In addition, AA patients demonstrated more severe periodontal damages with 69.3% moderate and severe periodontitis, compared to only 16.0% in the non-AA group. Using AA as the dependent variable and all the potential risk factors as covariates (e.g., gender, age, smoking, obesity, diabetes, hypertension, and hyperlipidemia), a logistic regression analysis was performed to show clinical attachment loss (CAL) being an independent risk factor for AA (OR = 2.309, 95% CI: 1.623–3.284, p = 0.000). In comparison with the non-AA patients, more AA patients have poor oral hygiene habits and don’t have regular dental appointments for supra-gingival cleaning. Conclusion Poor periodontal condition and dental hygiene were identified in the AA patients, suggesting that periodontitis-induced CAL may play a role in AA disease mechanisms.

A four‐channel directly modulated square‐rectangular laser array was demonstrated in 1.3 μm wavelength range with the wavelength interval about 5 nm. The laser array shows stable single mode operation with the side‐mode suppression ratio (SMSR) over 30 dB, 3‐dB modulation bandwidth above 11.8 GHz and an open‐eye diagram is obtained at data rates of 10 Gb/s, and the relative intensity noise (RIN) about −138 dB/Hz up to 5 GHz for all channels. [ABSTRACT FROM AUTHOR]

Severe voltage distortion, due to power system harmonic resonance, has been reported in recent years. This issue becomes more significant in high penetration of a photovoltaic (PV) network. A conventional voltage detection active filter operates as similar conductance for all harmonic frequencies to resolve this problem whether in a fixed conductance command or in an automatic gain adjustment control. However, its filtering capability is impeded by the mismatch between the active filter and the radial line, and the voltage distortion may still be significant. This paper proposes a discrete frequency tuning active filter to suppress power system harmonics. The active filter operates as variable conductance for each individual harmonic frequency. Each harmonic conductance is dynamically adjusted according to the corresponding harmonic voltage distortion of the active filter installation point in response to increase or decrease of nonlinear loads, or variation of resonant frequency in the power system. The mismatching problem between the feeder impedance and the active filter can be avoided effectively. Therefore, harmonic voltage distortion can be maintained at an allowable level throughout the feeder with lower peak current and lower rms current of the active filter, and loads installed at various locations of the power system receive more uniform voltage waveform. Index Terms--Active power filter, harmonic resonance, harmonic voltage damping.