公开(公告)号：US3717769A

公开(公告)日：1973-02-20

申请号：US3717769D

申请日：1971-08-16

Applicant: BELL TELEPHONE LABOR INC

Inventor： HUBBARD W ,  LI T

IPC: H04B10/02 ,  H04B10/18 ,  H04B9/00

CPC classification number: H04B10/2507

Abstract: BECAUSE OF IMPERFECTIONS IN OPTICAL FIBERS, LIGHT PROPAGATING THEREALONG IS CONTINUOUSLY BEING SCATTERED AND RESCATTERED. SOME OF THIS SCATTERED ENERGY IS TRAPPED WITHIN THE FIBER IN A PROPAGATING MODE AND ULTIMATELY REACHES THE OUTPUT OF THE FIBER DELAYED RELATIVE TO THE INPUT SIGNAL. IT IS SHOWN THAT THE DOUBLE-REVERSE SCATTERING RESPONSE OF A FIBER IS VERY NEARLY THE SAME AS THE RESPONSE OF AN R-C INTEGRATOR FOR THE SAME INPUT. ACCORDINGLY, THE EFFECTS OF DOUBLE-REVERSE SCATTERING INTERFERENCE CAN BE SUBSTANTIALLY REDUCED BY PASSING A PORTION OF THE RECEIVED SIGNAL THROUGH AN R-C INTEGRATOR AND INJECTING THE INTEGRATED SIGNAL THUS PRODUCED BACK INTO THE MAIN SIGNAL PATH IN TIME COINCIDENCE WITH THE SIGNAL SO AS TO CANCEL THE INTERFERENCE COMPONENT.