Video Experimental Relacionado

Updated: Jan 8, 2026

Transmission of Multiple Signals through an Optical Fiber Using Wavefront Shaping

Transmission of Multiple Signals through an Optical Fiber Using Wavefront Shaping

Published on: March 20, 2017

Enfoque de modulación QAM de orden ultra alto basado en la conformación conjunta de descomposición de constelación

Ying Zhang, Jiaqi Wang, Wenxiang Yao

|December 19, 2025

Abstract:

This article proposes a local constellation decomposition joint shaping scheme for ultra-high-order quadrature amplitude modulation (QAM) signals. The method first applies probabilistic shaping (PS) to the global constellation, followed by decomposition into local constellations, geometric shaping (GS) at the local level, and recombination for transmission. Delta-sigma modulation (DSM) is employed to facilitate the transmission of ultra-high-order 16384QAM in an intensity modulation direct detection (IMDD) system. Simulation studies are conducted to evaluate transmission performance under varying information entropy levels. The results demonstrate that, for the same information entropy, the bit error rate (BER) performance of 16384QAM with the proposed joint shaping scheme and DSM outperforms that of conventional 16384QAM with DSM. Experimental validation over 25 km single-mode fiber (SMF) further confirms the effectiveness of the proposed approach for ultra-high-order communication systems based on DSM. Additionally, the receiver sensitivity of the system improves by approximately 0.6 dB for every 1 bit/symbol reduction in information entropy.

Palabras clave:

modulación QAM de orden ultra alto conformación conjunta descomposición de constelación local detección directa de modulación de intensidad (IMDD)modulación Delta-sigma (DSM)sensibilidad del receptor tasa de error de bits (BER)

Más Videos Relacionados

Shaping the Amplitude and Phase of Laser Beams by Using a Phase-only Spatial Light Modulator

Shaping the Amplitude and Phase of Laser Beams by Using a Phase-only Spatial Light Modulator

Published on: January 28, 2019

Quasi-light Storage for Optical Data Packets

Quasi-light Storage for Optical Data Packets

Published on: February 6, 2014

Videos de Conceptos Relacionados

¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)

¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)

When proton-coupled carbon-13 spectra are simplified by a broadband proton decoupling technique, structural information about the coupled protons is lost. Distortionless enhancement by polarization transfer (DEPT) is a technique that provides information on the number of hydrogens attached to each carbon in a molecule. While the DEPT experiment utilizes complex pulse sequences, the pulse delay and flip angle are specifically manipulated. The resulting signals have different phases depending on...

Linear Approximation in Frequency Domain

Linear Approximation in Frequency Domain

Linear systems are characterized by two main properties: superposition and homogeneity. Superposition allows the response to multiple inputs to be the sum of the responses to each individual input. Homogeneity ensures that scaling an input by a scalar results in the response being scaled by the same scalar.
In contrast, nonlinear systems do not inherently possess these properties. However, for small deviations around an operating point, a nonlinear system can often be approximated as linear....

IR Spectrum Peak Splitting: Symmetric vs Asymmetric Vibrations

IR Spectrum Peak Splitting: Symmetric vs Asymmetric Vibrations

Identical bonds within a polyatomic group can stretch symmetrically (in-phase) or asymmetrically (out-of-phase). Similar to hydrogen bonding, these vibrations also influence the shape of the IR peak. Generally, asymmetric stretching frequencies are higher than symmetric stretching frequencies. For example, primary amines exhibit two distinct IR peaks between 3300–3500 cm−1 corresponding to the symmetric and asymmetric N-H stretching, while secondary amines exhibit a single...

Upsampling

Upsampling

Managing signal sampling rates is essential in digital signal processing to maintain signal integrity. A decimated signal, characterized by a reduced frequency range due to its lower sampling rate, can be upsampled by inserting zeros between each sample. This upsampling process expands the original spectrum and introduces repeated spectral replicas at intervals dictated by the new Nyquist frequency. To refine this zero-inserted sequence, it is passed through a lowpass filter with a cutoff...

Area Computation by the Alternative Coordinate Method

Area Computation by the Alternative Coordinate Method

The alternative coordinate method, also known as the Shoelace Formula, is a technique for determining the area of a traverse using Cartesian coordinates. This method relies on the sequential arrangement of x and y coordinates for each point of the shape, ensuring accuracy and ease of application.In this approach, each corner's x and y coordinates are listed as fractions, with the x-coordinate as the numerator and the y-coordinate as the denominator. These coordinates are arranged sequentially...

IR Spectrum Peak Intensity: Dipole Moment

IR Spectrum Peak Intensity: Dipole Moment

The dipole moment of a bond is the product of the partial charge on either atom and the distance between them. Dipole moments influence the efficiency of IR absorption and the peak intensity. When a bond with a dipole moment is placed in an electric field, the direction of the field determines if the bond is compressed or stretched. Electromagnetic radiation consists of an electric field component that rapidly reverses direction. It follows that polar bonds are alternately stretched and...