Optical signal modulation

A technology of optical signal and optical modulation, applied in the direction of modulation carrier system, optics, nonlinear optics, etc., to achieve the effect of avoiding severe distortion

Active Publication Date: 2011-08-31
TELEFON AB LM ERICSSON (PUBL)
View PDF2 Cites 4 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, it still requires electrical processing of the input bit sequence to apply quadrant differential encoding

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Optical signal modulation
  • Optical signal modulation
  • Optical signal modulation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0074] refer to Figures 1 to 4 , the first embodiment of the present invention provides a 16-QAM optical modulator 10 in the form of 2 n - A quadrature amplitude modulation (QAM) optical modulator comprising an optical input 11 , a first optical modulation device 12 and a second optical modulation device 20 . In this embodiment, an optical signal to be modulated is received by an optical input 11 and coupled to a first optical modulation device 12, which applies a quadrature amplitude modulation scheme to the optical signal, thereby generating an intermediate optical signal. The intermediate optical signal is then fed to a second optical modulation device 20, which is configured to selectively rotate the phase of the intermediate optical signal. The 16-QAM modulated optical signal is thus output from the optical modulator 10, which has such Figure 4 The shown square constellation diagram 19 includes 16 constellation points 16 distributed on 4 quadrants of the constellation...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

No PUM Login to view more

Abstract

A 2n-QAM (e.g. 16-QAM) optical modulator 10 comprising cascaded I-Q modulators (22, 38). The first I-Q modulator 22 applies 2n-2 (e.g. 4) QAM to an optical signal, having a constellation diagram with the 2n-2 constellation points located in quadrant I. The second I-Q modulator (38) subsequently applies a quaternary phase-shift keying (QPSK) modulation scheme to the optical signal, thereby rotating the constellation points of the 2n-2-QAM modulation scheme to quadrants II, III and IV, to produce a 2n-QAM modulation constellation diagram. The rotation causes the 2n-QAM modulator to inherently apply four quadrant differential encoding to the optical signal. A method of 2n-QAM optical modulation is also provided and optical signal transmission apparatus comprising the 2n-QAM optical modulator.

Description

technical field [0001] The present invention relates to 2 n Quadrature Amplitude Modulation (QAM) Optical Modulator, 2 n The method of quadrature amplitude modulation and including 2 n - An optical signal transmission device for a QAM optical modulator. Background technique [0002] Quadrature amplitude modulation with 16 levels (16-QAM) is one of the candidate modulation formats for 100 gigabits per second (Gbit / s) transmission into optical fiber. It encodes four bits on a constellation of sixteen points, and transmits the in-phase and quadrature components of the signal with four different amplitude values. When considering the polarization-diverse 16-QAM format for transmission at 100 Gbit / s, the symbol rate required by the transmitter is 12.5 Gbaud. Even at this reduced symbol rate, the generation of multi-level drive signals can be complicated. A further complication arises from the necessity to apply differential digital encoding to the optical signal prior to opt...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/20H04L27/34H04L27/36H04B10/516H04B10/54H04B10/548
CPCH04B10/541H04B10/548H04L27/36H04B10/5161H04L27/2096H04L27/3488G02F1/225G02F2201/16
Inventor M·塞康迪尼F·卡瓦利耶
Owner TELEFON AB LM ERICSSON (PUBL)
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap