Design of photonic crystal fiber with elliptical air-holes to achieve simultaneous high birefringence and nonlinearity

A new type of V-shaped photonic crystal fiber with elliptical air-holes is proposed to realize simultaneous high bire- fringence and nonlinearity at a wavelength of 1.55 μm. The full vector finite element method was adopted to investigate its characteristics, including birefringence, nonlinearity, and dispersion. The PCF exhibited a very high birefringence of 2.89x10-2 and very high nonlinear coefficient of 102.69 W-1 .km 1. In particular, there were two zero-dispersion wave- lengths （ZDWs） in the visible （X： 640-720 nm and Y： 730-760 nm） and near-infrared regions （X： 1050-1606 nm and Y： 850-1500 nm）. The combination of high birefringence and nonlinearity allowed the PCF to maintain the polarization state and generate a broadband super continuum, with potential applications in nonlinear optics.

Widely Tunable Fiber Ring Laser with High Concentration Erbium-Doped Fiber

We report a high power and widely tunable erbium-doped fiber (EDF) ring laser using 1480nm pump and high concentration EDF. Large tuning range up to 105nm (1513-1618 nm) has been obtained by optimizing of the EDF length.

High Azimuthal Index Doughnut Beam Generated by Liquid Crystal Spiral Phase Plates

A novel technique of producing azimuthal index 1>1 doughnut beam of good quality by use of multi-liquid crystal cells is presented, it has the advantages of high conversion efficiency and flexibility.

Coupling Considerations for Fabrication of Acoustooptic Tunable Filter

Induced acoustic wave to bare fiber through various types of horn are examined. The center wavelength and extinction ratio of the notch filter are dynamically tunable and dependent on the RF signals.

Splicing on Condensed Photonic Crystal Fiber Using CO_2 Laser

Condensation in the air-holes of photonic crystal fiber results in bubble development during the electric arc splicing is first reported. The condensation can be removed by laser splicing; and 1.4dB splice loss has been achieved.

Experimental Investigation of Macro-Bending Loss in Large Mode Area Photonic Crystal Fibers

We measured macro-bending losses for two large mode area photonic crystal fibers. Experimental results show that macro-bending loss and loss window are dependent on the parameter d/∧ and number of air-holes ring in the cladding.

Cellular-resolution in vivo tomography in turbid tissue through digital aberration correction

Noninvasive tomographic imaging of cellular processes in vivo may provide valuable cytological and histological information for disease diagnosis.However,such strategies are usually hampered by optical aberrations caused by the imaging system and tissue turbidity.State-of-the-art aberration correction methods require that the light signal be phase stable over the full-field data acquisition period,which is difficult to maintain during dynamic cellular processes in vivo.Here we show that any optical aberrations in the path length difference(OPD)domain can be corrected without the phase stability requirement based on maximum intensity assumption.Specifically,we demonstrate a novel optical tomographic technique,termed amplitude division aperture synthesis optical coherence tomography(ADAS-OCT),which corrects aberrations induced by turbid tissues by physical aperture synthesis and simultaneously data acquisition from sub-apertures.Even with just two subapertures,ADAS-OCT enabled in vivo visualization of red blood cells in human labial mucosa.We further demonstrated that adding sub-apertures could significantly scale up the aberration correction capability.This technology has the potential to impact a number of clinical areas where noninvasive examinations are preferred,such as blood count and cancers detection.

Rayleigh backscattering noise in single-fiber Ioopback duplex WDM-PON architecture

This paper investigated the impact of Rayleigh backscattering （RB） noise in the proposed wavelength- division-multiplexed （WDM） single-fiber loopback access network. RB noise＇s impacts on the downstream and upstream service were discussed in details. It was found that the receiver sensitivity was less sensitive when the seeding-light power was below - 12.6 dBm. And for the uplink RB noise, a higher reflective semiconductor optical amplifier （RSOA）＇s bias current results in lower receiver sensitivity.

Self-Correcting Recurrent Neural Network for Acute Kidney Injury Prediction in Critical Care

Background.In critical care,intensivists are required to continuously monitor high-dimensional vital signs and lab measurements to detect and diagnose acute patient conditions,which has always been a challenging task.Recently,deep learning models such as recurrent neural networks(RNNs)have demonstrated their strong potential on predicting such events.However,in real deployment,the patient data are continuously coming and there is no effective adaptation mechanism for RNN to incorporate those new data and become more accurate.Methods.In this study,we propose a novel self-correcting mechanism for RNN to fill in this gap.Our mechanism feeds prediction errors from the predictions of previous timestamps into the prediction of the current timestamp,so that the model can“learn”from previous predictions.We also proposed a regularization method that takes into account not only the model’s prediction errors on the labels but also its estimation errors on the input data.Results.We compared the performance of our proposed method with the conventional deep learning models on two real-world clinical datasets for the task of acute kidney injury(AKI)prediction and demonstrated that the proposed model achieved an area under ROC curve at 0.893 on the MIMIC-III dataset and 0.871 on the Philips eICU dataset.Conclusions.The proposed self-correcting RNNs demonstrated effectiveness in AKI prediction and have the potential to be applied to clinical applications.