Fiber optic telephone loop network

[54] FIBER OPTIC TELEPHONE LOOP NETWORK

[75] Inventor: James A. Bears, Osgoode, Canada

[73] Assignee: Northern Telecom Limited, Montreal, Canada

[21] Appl. No.: 810,067

[22] Filed: Dec. 19,1991

[51] Int. CI.5 H04J 14/00; H04B 10/12

[52] U.S. a 359/137; 359/125;

348/6

[58] Field of Search 359/118, 119, 121, 126,

359/137,125, 117; 358/84, 86; 455/3.1,4.1,4.2,

5.1

[56] References Cited

U.S. PATENT DOCUMENTS

4,491,983 1/1985 Pinnow 359/118

4,686,667 8/1987 Ohnsorge 359/118

4,709,418 11/1987 Fox 359/118

4,891,694 1/1990 Way 359/125

5,136,411 8/1992 Paik 359/125

FOREIGN PATENT DOCUMENTS

9109478 6/1991 PCT Int'l Appl 359/125

OTHER PUBLICATIONS

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f.on Communications, Apr. 14-19, 1990, vol.4, pp. 1550-1554.

J. D. Jensen et al, "Fiber to the Pedestal . . . Then What?", Conf.Record, IEEE Int'l Conf.on Communications, Apr. 15-19, 1990, vol.4, pp. 32-34. S. Pendleton-Hughes et al, "Forty Channel Wavelength Multiplexing for Short Haul Wideband Communication Networks", Tech.Digest, 11th European Conf. On Optical Communication, Oct. 1-4, 1985, vol.1, pp. 649-652.

L. Bersiner et al, "Bidirectional WDM Transmission with Spectrum Sliced LEDs", Journal of Optical Communications, vol.11, No.2, Jun. 1990, entire document. "What Cost Local Loop?", C. Nelson, Telephony, Oct. 29, 1990, pp. 38-42.

"Break on Through to the Other Side", C. T. Hawley,
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Primary Examiner—Leslie Pascal

Attorney, Agent, or Firm—Yoshiharu Toyooka

Novel fiber optic telephone loop networks are disclosed. In the networks, single mode fiber optics are used for feeder and distribution segments of the loop but multimode fiber optics are used for the drops. The use of the multimode fiber optics has permitted the use of less costly optoelectronic devices. Surface light emitting diodes are such economical but reliable parts. Fiber service terminals located near customer homes convert single mode operation to the multimode operation. The networks are relatively easy to install and upgrade and are very economically competitive with other known FTTC and FTTH schemes.

2 Claims, 5 Drawing Sheets