Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Monitoring and in-line compensation of polarization dependent loss for lightwave systems

a technology of polarization dependent loss and lightwave system, which is applied in the direction of fibre transmission, distortion/dispersion elimination, electrical apparatus, etc., can solve the problems of wdm system, polarization dependent loss (pdl) is also a key limiting factor, and the practical scheme of fast pdl monitoring that is necessary for dynamic compensation has not been reported

Inactive Publication Date: 2008-02-14
UNIV OF SOUTHERN CALIFORNIA
View PDF11 Cites 5 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention is about a system and method for compensating for performance degradation in a multi-wavelength fiber-optic communication system caused by polarization dependent loss (PDL). The invention uses a continuous-wave ancillary wavelength with an unknown state of polarization (SOP) that is scrambled periodically in time. The real-time measured optical signal power variation is used as an error signal to adjust at least one polarization controller. The invention can be used in high-bit-rate digital fiber transmission systems, reconfigurable optical networks, transmission of analog radio-frequency and millimeter-wave signals over fiber, dynamic compensation of polarization mode dispersion and polarization dependent loss in high-speed optical communication systems, long-haul optical transmission, and analog fiber-optic system for wireless communications. The invention provides a practical PDL monitoring scheme and a functional dynamic PDL compensator.

Problems solved by technology

It has become clear recently that polarization dependent loss (PDL) is also a key limiting factor in high-capacity wavelength multiplexing WDM) systems, because various optical networking components and erbium doped fiber amplifiers (EDFAs) may produce PDL.
Moreover, a practical scheme of fast PDL monitoring that is necessary for dynamic compensation has not been reported.
This scheme limits the PDL measurement time and / or accuracy in the presence of noise.

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
  • Monitoring and in-line compensation of polarization dependent loss for lightwave systems
  • Monitoring and in-line compensation of polarization dependent loss for lightwave systems
  • Monitoring and in-line compensation of polarization dependent loss for lightwave systems

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0019]FIG. 1 illustrates in-line monitoring and dynamic compensation of PDL, in accordance with embodiments of the present invention. To monitor PDL along a cascaded EDFA link 10 and avoid the influence of EDFA transients, fast polarization scrambler 12 is inserted at the starting point of link 10. The PDL value is obtained from either the peak-to-peak variation or the standard deviation of the photo-detected signal' power. PDL 11-1, . . . , 11-N at every optical node 13-1, . . . , 13-N between transmission fibers 14-1, . . . , 14-N represents the unavoidable, deleterious polarization dependent loss in various active and passive optical components, for example EDFAs, optical switches, couplers, and / or isolators. Because the polarization coupling between these components may vary with time, the total PDL of the optical module or node 13-1, . . . , 13-N is also time-variable, making the dynamic monitoring and compensation of PDL valuable for optimization of overall system performance,...

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 multi-wavelength optical signal copropagates through a fiber-optic communication link with a continuous-wave ancillary wavelength having an unknown state of polarization (SOP), which is scrambled periodically in time. The instantaneous value of polarization dependent loss (PDL) in the ancillary wavelength is monitored in real time, and is used as an error signal to adjust at least one polarization controller. Polarization scrambling is performed by periodically changing the SOP with time, such that the polarization-scrambled optical signal covers approximately an entire Poincaré sphere surface, preferably uniformly, during each time period. At an optical node between fibers, an adjustable PDL compensator contains two ordered pairs each consisting of one polarization controller and one optical element introducing fixed PDL.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims priority benefit of U.S. Provisional Application 60 / 276,799 filed Mar. 16, 2001.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT [0002] The invention was made in part with Government support by Defense Advanced Research Projects Agency (DARPA) under the Air Force Grant Number: F30602-98-1-0196. The Government has certain rights in the invention.BACKGROUND OF THE INVENTION [0003] High data rate optical fiber communication is one of the fastest growing areas in the telecommunication industry. Compensation of lightwave polarization effects is one of the key enabling technologies for high-speed and long haul data transmission. There has been much interest in the limitations of high-speed lightwave systems caused by the stochastic nature of polarization mode dispersion (PMD). It has become clear recently that polarization dependent loss (PDL) is also a key limiting factor in high-capacity wavelength mul...

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(United States)
IPC IPC(8): H04B10/04H04B10/06
CPCH04B10/2572
Inventor YU, QIANYAN, LIANSHANWILLNER, ALAN E.
Owner UNIV OF SOUTHERN CALIFORNIA
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products

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

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com