Optical Fiber Solutions (Denmark)

Spatial mode-count scalability in optical fibers is of paramount importance for addressing the upcoming information-capacity crunch, reducing energy consumption per bit, and for enabling advanced quantum computing networks, but this scalability is severely limited by perturbative mode mixing. We show an alternative means of light guidance, in which light's orbital angular momentum creates a centrifugal barrier for itself, thereby enabling low-loss transmission of light in a conventionally forbidden regime wherein the mode mixing can be naturally curtailed. This enables kilometer-length-scale transmission of a record ~50 low-loss modes with cross-talk as low as -45 decibels/kilometer and mode areas of ~800 square micrometers over a 130-nanometer telecommunications spectral window. This distinctive light-guidance regime promises to substantially increase the information content per photon for quantum or classical networks.

We report the numerical and experimental study of probe pulse deformation in a forward-pumped distributed Raman amplifier on a 40-km standard single mode fiber. Distributed Raman amplification can improve the range of OTDR-based sensing systems, but it could result in pulse deformation. A smaller Raman gain coefficient can be used to mitigate pulse deformation. The sensing performance can still be maintained by compensating for the decrease in the Raman gain coefficient by increasing the pump power. The tunability of the Raman gain coefficient and pump power levels are predicted while keeping the probe power below the modulation instability limit.

We model the full image formation process in FD-OCM for a Bessel-like LP02 illumination beam as well as Gaussian beams. The LP02 beam generated in a HOM fiber enables design flexibility and an extended DOF.

Abstract The development of new immunomodulatory agents can impact various areas of medicine. In particular, compounds with the ability to modulate innate immunological pathways hold significant unexplored potential. Herein, we report a modular synthetic approach to the macrodiolide natural product (−)‐vermiculine, an agent previously shown to possess diverse biological effects, including cytotoxic and immunosuppressive activity. The synthesis allows for a high degree of flexibility in modifying the macrocyclic framework, including the formation of all possible stereoisomers. In total, 18 analogues were prepared. Two analogues with minor structural modifications showed clearly enhanced cancer cell line selectivity and reduced toxicity. Moreover, these compounds possessed broad inhibitory activity against innate immunological pathways in human PBMCs, including the DNA‐sensing cGAS‐STING pathway. Initial mechanistic characterization suggests a surprising impairment of the STING‐TBK1 interaction.

We report on the multiplexing of 12 spatial and polarization channels and 120 wavelength channels in the C -band, each carrying 16 quadratic-amplitude modulation symbols at 30 GBd over graded-index few-mode fiber. A combination of multiple fiber spools with positive and negative modal dispersion values is exploited to form a 59-km link with 0.35-ns differential mode group delay. The link is placed inside a sixfold synchronized recirculating loop transmission setup. Photonic lanterns with low insertion and mode-dependent loss are employed to excite the six spatial modes in the few-mode fiber. A net transmission rate of 138 Tb/s at a spectral efficiency of 34.91 b/s/Hz over 590 km is demonstrated.

We provide additional details on the bend perturbation calculation necessitated by labelling errors in Fig. 3(a) of Optica2, 267 (2015)OPTIC82334-253610.1364/OPTICA.2.000267, and provide one citation missing from the original manuscript.

We demonstrate simple and intuitive methods, for dispersion optimization and characterization of highly nonlinear fiber (HNLF) for use in four-wave-mixing (FWM) based time lens applications. A composite dispersion-flattened HNLF is optimized for high bandwidth time lens processing, by segmentation to mitigate FWM impairments due to dispersion fluctuations. The fiber is used for FWM conversion of 32 WDM-channels with 50 GHz spacing in a time lens, with -4.6 dB total efficiency, and <1 dB per-channel efficiency difference. The novel characterization method is based on two tunable continuous-wave lasers. The method is experimentally verified to predict the spectral output profile of time lenses for broadband multicarrier input, with detailed numerical simulations for support.

We demonstrate 13.4km propagation of OAM L=7 fiber modes with record low 0.8dB/km loss via a circulating fiber loop experiment. For well-designed fibers, we demonstrate that OAM modes can travel distances relevant for large-scale data centers.

The promise of the infinite-dimensionality of orbital angular momentum (OAM) and its application to free-space and fiber communications has attracted immense attention in recent years. In order to facilitate OAM-guidance, novel fibers have been proposed and developed, including a class of so-called ring-fibers. In these fibers, the wave-guiding region is a high-index annulus instead of a conventional circular core, which for reasons related to polarization-dependent differential phase shifts for light at waveguide boundaries, leads to enhanced stability for OAM modes. We review the theory and implementation of this nascent class of waveguides, and discuss the opportunities and limitations they present for OAM scalability.

Improved nonlinear fiber designs have recently demonstrated intrinsically stable phase-matching. They remove dispersion variation limits, enabling efficient devices, for example a low-threshold oscillator tunable across wavelengths from 1.7-2.1 microns.