Widely Tunable Photonic Filter Based on Equivalent Chirped Four-Phase-Shifted Sampled Bragg Gratings.

We have developed an integrated dual-band photonic filter (PF) utilizing equivalent chirped four-phase-shifted sidewall-sampled Bragg gratings (4PS-SBG) on a silicon-on-insulator platform. Using the reconstruction equivalent-chirp technique, we designed linearly chirped 4PS Bragg gratings with two π-phase shifts (π-PSs) positioned at 1/3 and 2/3 of the grating cavity, introducing two passbands in the + first order channel. Leveraging the significant thermo-optic effect of silicon, dual-band tuning is achieved through integrated microheaters (MHs) on the chip surface.

Continuous phase modulation technology based on grating period interval for high grating coupling coefficient and precise wavelength control.

A novel, to the best of our knowledge, grating modulation technique for distributed feedback laser arrays is proposed and demonstrated. This method modifies the initial phase within each grating period, applying a total phase shift that increments in an arithmetic progression, realizing laser arrays with channel spacings of 0.493 nm, 0.

Multi-wavelength DFB laser based on a sidewall third-order four phase-shifted sampled Bragg grating with uniform wavelength spacing.

We present the first, to our knowledge, demonstration of a 1550 nm multi-wavelength distributed feedback (MW-DFB) laser employing a third-order, four-phase-shifted sampled sidewall grating. By utilizing linearly chirped sampled gratings and incorporating multiple true π-phase shifts within a cavity, we achieved and experimentally validated a four-wavelength laser with a channel spacing of 0.4 nm.

Narrow linewidth distributed feedback lasers utilizing distributed phase shift.

This study proposes and experimentally demonstrates a distributed feedback (DFB) laser with a distributed phase shift (DPS) region at the center of the DFB cavity. By modeling the field intensity distribution in the cavity and the output spectrum, the DPS region length and phase shift values have been optimized. Experimental comparisons with lasers using traditional π-phase shifts confirm that DFB lasers with optimized DPS lengths and larger phase shifts (up to 15π) achieve stable single longitudinal mode operation over a broader current range, with lower threshold current, higher power slope efficiency, and a higher side mode suppression ratio (SMSR).

FGF21-dependent alleviation of cholestasis-induced liver fibrosis by sodium butyrate.

Background: The beneficial effects of fibroblast growth factor 21 (FGF21) and sodium butyrate (NaB) on protection against cholestasis-induced liver fibrosis are not well known. This study aimed to explore the effects of FGF21 and NaB on bile duct ligation (BDL)-induced liver fibrosis.

Methods: Wild-type (WT) and FGF21 knockout (KO) mice received BDL surgery for 14 days.

Dual-wavelength distributed feedback laser array based on four-phase-shifted sampled Bragg grating for terahertz generation.

We propose and experimentally demonstrate a dual-wavelength distributed feedback (DFB) laser array utilizing a four-phase-shifted sampled Bragg grating. By using this grating, the coupling coefficient is enhanced by approximately 2.83 times compared to conventional sampled Bragg gratings.

Optimized strategies of cloud droplet distribution retrieval using satellite multi-directional polarimetric optical measurements: information content approach.

Multi-directional polarized optical sensors are increasingly vital in passive remote sensing, deepening our understanding of global cloud properties. Nevertheless, uncertainty lingers on how these observations can contribute to our knowledge of cloud diversity. The variability in cloud PSD (Particle Size Distribution) significantly influences a wide array of cloud characteristics, while unidentified factors in RT (Radiative Transfer) may introduce errors into the cloud PSD retrieval algorithm.

The role of iron-rich hydrosaline liquids in the formation of Kiruna-type iron oxide-apatite deposits.

Kiruna-type iron oxide-apatite (IOA) deposits, an important source of iron, show close associations with andesitic subvolcanic intrusions. However, the processes of ore formation and the mechanism controlling iron concentration remain uncertain. Here, we report the widespread presence of high-temperature (>800°C) water-poor multisolid hydrosaline liquid inclusions in pre- and syn-ore minerals from IOA deposits of eastern China.

Millimeter-wave generation based on a monolithic dual-wavelength DFB laser with four phase-shifted sampled gratings and equivalent chirp technology.

A dual-wavelength DFB laser array based on four phase-shifted grating and equivalent chirp technology is first proposed, fabricated, and experimentally demonstrated. The dual-wavelength emitting is achieved by symmetrically introducing two π phase shifts into a chirped four phase-shifted sampled grating cavity. Meanwhile, the beating signal of the dual-wavelength output is stabilized by applying an electro-absorption modulator integrated at the rear of the cavity.

DFB laser array based on four phase-shifted sampled Bragg gratings with precise wavelength control.

A four-laser array based on sampled Bragg grating distributed feedback (DFB) lasers in which each sampled period contains four phase-shift sections is proposed, fabricated, and experimentally demonstrated. The wavelength spacing between adjacent lasers is accurately controlled to 0.8 nm ± 0.

Conventional MRI for diagnosis of subacute combined degeneration (SCD) of the spinal cord due to vitamin B-12 deficiency.

Subacute combined degeneration of the spinal cord (SCD) is often found in vitamin B-12 deficiency and typically shows hyperintensity on T2-weighted images of the lateral and posterior columns. The purpose of the study was to evaluate the use of conventional magnetic resonance examination in diagnosing SCD. Thirty-six patients were clinically confirmed and retrospectively analyzed; conventional spine MRIs were available for all patients and eight of them had contrast enhancement MRIs.