Achievable information rate optimization in C‑band optical fber communication system

Optical fber communication networks play an important role in the global telecommunication network.However,nonlinear efects in the optical fber and transceiver noise greatly limit the performance of fber communication systems.In this paper,the product of mutual information(MI)and communication bandwidth is used as the metric of the achievable information rate(AIR).The MI loss caused by the transceiver is also considered in this work,and the bit-wise MI,generalized mutual information(GMI),is used to calculate the AIR.This loss is more signifcant in the use of higher-order modulation formats.The AIR analysis is carried out in the QPSK,16QAM,64QAM and 256QAM modulation formats for the communication systems with diferent communication bandwidths and transmission distances based on the enhanced Gaussian noise(EGN)model.The paper provides suggestions for the selection of the optimal modulation format in diferent transmission scenarios.

Fiber structures and material science in optical fiber magnetic field sensors

Magnetic feld sensing plays an important role in many felds of scientifc research and engineering applications.Benefting from the advantages of optical fbers,the optical fber-based magnetic feld sensors demonstrate characteristics of light weight,small size,remote controllability,reliable security,and wide dynamic ranges.This paper provides an overview of the basic principles,development,and applications of optical fber magnetic feld sensors.The sensing mechanisms of fber grating,interferometric and evanescent feld fber are discussed in detail.Magnetic fuid materials,magneto-strictive materials,and magneto-optical materials used in optical fber sensing systems are also introduced.The applications of optical fber magnetic feld sensors as current sensors,geomagnetic monitoring,and quasi-distributed magnetic sensors are presented.In addition,challenges and future development directions are analyzed.

Emerging Applications of Optical Fiber‑Based Devices for Brain Research

Research in neuroscience and neuroengineering has attracted tremendous interest in the past decades.However,the complexity of the brain tissue,in terms of its structural,chemical,mechanical,and optical properties,makes the interrogation of biophysical and biochemical signals within the brain of living animals extremely challenging.As a viable and versatile tool for brain studies,optical fber based technologies have provided exceptional opportunities to unravel the mysteries of the brain and open the door for clinical applications in the treatment,diagnosis,and prevention of neurological diseases.Typically,optical fbers with diameters from 10 to 1000μm are capable of guiding and delivering light to deep levels of the living tissue.Moreover,small dimensions of such devices along with their fexibility and light weight paved the way for understanding the complex behaviours of living and freely moving mammals.This article provides a review of the emerging applications of optical fbers in neuroscience,specifcally in the mammalian brain.Representative utilities,including optogenetics,fuorescence sensing,drug administration and phototherapy,are highlighted.We also discuss other biological applications of such implantable fbers,which may provide insights into the future study of brain.It is envisioned that these and other optical fber based techniques ofer a powerful platform for multi-functional neural activity sensing and modulation.