Ultra-fast SOP rotation tracking and its enabled feedforward adaptive equalization based on superimposed chirp pilot.

We propose to track state of polarization (SOP) rotation by utilizing chirp pilots processed through fractional Fourier transform (FrFT). Superimposed on dual-polarization data signal, the chirp pilots with different FrFT rotation orders can converge to fractional energy peaks and then be distinguished by combining FrFT with MIMO structure. Consequently, SOP rotation resulting in energy distribution can be estimated by leveraging aggregated peaks in the matched fraction domain.

Forward polarization sensing triggered area-focus DAS over a bidirectional coherent network.

Empowering optical communication networks with sensing capabilities is an emerging trend. In this Letter, we propose a method to preliminarily detect perturbations in a bidirectional coherent network by utilizing forward polarization information. This information acts as a trigger and provides prior knowledge to back-scattering-based distributed acoustic sensing (DAS), enabling more detailed event recovery.

CD-aware non-orthogonal DFT-precoding for C-band IM/DD multicarrier signals over a 50-km dispersion-uncompensated link.

In this paper, a chromatic-dispersion-aware non-orthogonal discrete Fourier transform precoding (CDA-NODFTP) scheme is proposed for CD-constrained intensity-modulation and direct detection (IM/DD) multicarrier-signal transmission systems. The performance of the proposed CDA-NODFTP scheme is experimentally evaluated and compared with conventional DFTP and NODFTP schemes over a 50-km C-band dispersion-uncompensated link, utilizing 90-Gb/s orthogonal frequency division multiplexing (OFDM) and filter bank multicarrier (FBMC) signals. Experimental results show that the proposed CDA-NODFTP with adaptive spectral compression outperforms conventional DFTP, NODFTP, and the non-precoding schemes in terms of bit error rate (BER) performance.

Anisotropy-free arrayed waveguide gratings on X-cut thin film lithium niobate platform of in-plane anisotropy.

Arrayed waveguide grating is a versatile and scalable integrated light dispersion device, which has been widely adopted in various applications, including, optical communications and optical sensing. Recently, thin-film lithium niobate emerges as a promising photonic integration platform, due to its ability of shrinking largely the size of typical lithium niobate based optical devices. This would also enable multifunctional photonic integrated chips on a single lithium niobate substrate.

Photo- or Electrochemical Cyclization of Dienes with Diselenides to Access Seleno-Benzo[]azepines.

A cascade selenylation/cyclization of dienes with diselenides has been realized under visible-light irradiation or electrolysis conditions. Employing O or electricity as a "green" oxidant, this protocol provides a green and efficient method for an array of biologically important seleno-benzo[]azepine derivatives in moderate to good yields. The direct sunlight irradiation and gram-scale reaction render the approach practical and attractive.

Receive-diversity-aided power-fading compensation for C-band IM/DD OFDM systems.

A receive-diversity-aided power-fading compensation (RDA-PFC) scheme is proposed and demonstrated to eliminate the chromatic dispersion (CD)-induced power fading for C-band double-sideband (DSB) intensity modulation and direct detection (IM/DD) orthogonal frequency division multiplexing (OFDM) systems. By combining the responses before and after a dispersive element using a maximal-ratio combining (MRC) algorithm, the CD-induced power fading dips within the signal bandwidth of around 50 GHz can be effectively compensated for, which results in an up to 17.6-dB signal-to-noise ratio (SNR) improvement for the fading subcarriers after transmission over 10 km of standard single-mode fiber (SSMF).