A Highly Sensitive Intensity-Modulated Optical Fiber Magnetic Field Sensor Based on the Magnetic Fluid and Multimode Interference

Fiber-optic magnetic field sensing is an important method of magnetic field monitoring, which is essential for the safety of civil infrastructures, especially for power plant. We theoretically and experimentally demonstrated an optical fiber magnetic field sensor based on a single-mode-multimode-single-mode (SMS) structure immersed into the magnetic fluid (MF). The length of multimode section fiber is determined based on the self-image effect through the simulation. Due to variation characteristics of the refractive index and absorption coefficient of MF under different magnetic fields, an effective method to improve the sensitivity of SMS fiber structure is realized based on the intensity modulation method. This sensor shows a high sensitivity up to 0.097 dB/Oe and a high modulation depth up to 78% in a relatively linear range, for the no-core fiber (NCF) with the diameter of 125 μm and length of 59.8 mm as the multimode section. This optical fiber sensor possesses advantages of low cost, ease of fabrication, high sensitivity, simple structure, and compact size, with great potential applications in measuring the magnetic field

A Novel Trench-Assisted Optical Fiber With Ultra-Low Microbending Loss for the Full Ocean Depth Communication

A novel trench-assisted optical fiber with ultra-low microbending loss is proposed, which contains two trenches beside the core. The deformation distribution of the fiber axis caused by the wire mesh is in agreement with a Gaussian curve through the mechanical-optical model. By analyzing the microbending loss dependency on the optical fiber parameters, the optimal structure for the trench-assisted optical fiber was obtained. The fundamental mode field characteristics of the designed fiber under microbending were simulated using the finite element method, and the energy ratio of the designed fiber was obtained as 95.03%, which is larger than that of the conventional single-mode fiber. The designed fiber was fabricated based on the modified chemical vapor deposition (MCVD) technique and tested according to the modified plate method. The experimental results indicate that the fabricated fiber can support an ultra-low microbending loss of 0.0052 dB/m at 6 kg weight at 1550 nm, which is reduced by two orders of magnitude compared to the conventional single-mode fiber. The microbending loss measurement system exhibits good reliability and repeatability, and the measured results are consistent with the theory. The proposed optical fiber will be beneficial in improving the transmission efficiency of full ocean depth communication

Differential Expression of MiR-106b-5p and MiR-200c-3p in Newly Diagnosed Versus Chronic Primary Immune Thrombocytopenia Patients Based on Systematic Analysis

Background/Aims: MicroRNAs (miRNAs) have been described to have important roles in primary immune thrombocytopenia (ITP). To gain additional understanding, we have now further evaluated the involvement of miRNAs in ITP. Methods: Microarray experiments were performed to examine the expression profiles of miRNAs and mRNAs in samples from subjects with newly diagnosed ITP (G1), chronic ITP (G2), and normal controls. The systematic Pipeline of Outlier MicroRNA Analysis framework was applied to identify key miRNAs expressed in the G1 and G2 samples. Quantitative PCR and receiver operator characteristic curves were used to confirm the performance of key miRNAs. Results: Compared with normal controls, 14 miRNAs (12 over-expressed and 2 under-expressed) and 7 over-expressed miRNAs were identified as key in G1 and G2 samples, respectively. miR-106b-5p, miR-200c-3p, and miR-92a-3p exhibited significantly different expression profiles among the groups. In particular, miR-106b-5p and miR-200c-3p were expressed at higher levels in patients with ITP compared to the normal controls. Furthermore, these two miRNAs expressions were even higher in patients with chronic ITP. Conclusion: MiR-106b-5p and miR-200c-3p may represent valuable biomarkers of ITP, although further studies are needed to confirm and assess the value of these potential biomarkers at various stages of ITP

137 Gb/s PAM-4 Transmissions at 850 nm over 40 cm Optical Backplane with 25 G Devices with Improved Neural Network-Based Equalization

An improved neural network-based equalization method is proposed and experimentally demonstrated. The up-to-137 Gb/s transmission of four level pulse amplitude modulation (PAM-4) signals with 25 G class 850 nm optical devices is achieved over an in-house fabricated 40 cm optical backplane. An in-depth investigation is conducted regarding the impact of delayed taps and spans on equalization performance. A performance comparison of the proposed method with the traditional maximum likelihood sequence estimation (MLSE) and decision feedback equalization (DFE) is also undertaken. For the bit rate from 80 to 100 Gb/s, the proposed method achieves an adopted hard-decision forward error correction (HD-FEC) requirement at a received optical power (RoP) of −9 and −8 dBm, while DFE and MLSE cannot meet the HD-FEC requirement. When the bit rate increases from 120 to 137 Gb/s, the proposed equalization method still successfully maintains the acceptable system performance at an RoP of −4 and −2.5 dBm. Furthermore, the specific bit error rate (BER) performances for varied maximum achievable bit rate under different RoPs by applying MLSE and the proposed method are also analyzed. This provides an important potential solution to realize the future data centers