Browse Prior Art Database

Use of Relaxation Oscillation to Control Model Noise on Optical Fibers

IP.com Disclosure Number: IPCOM000113964D
Original Publication Date: 1994-Oct-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 1 page(s) / 7K

Publishing Venue

IBM

Related People

Hogan, WK: AUTHOR [+3]

Abstract

A method to choose a laser that exhibits favorable modulation and noise characteristics to operate in a fiber optic data link is disclosed.

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This is the abbreviated version, containing approximately 100% of the total text.

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Use of Relaxation Oscillation to Control Model Noise on Optical Fibers

A method to choose a laser that exhibits favorable modulation and noise characteristics to operate in a fiber optic data link is disclosed.

In current short-wave laser fiber-optic data links, the laser uses self-pulsation to control model noise on multimode fibers. In faster data link products, the self- pulsation laser is no longer suitable because the frequency of the self-oscillation is in the bandwidth on the transmitted data. When this self-oscillation gets too low in frequency, the transmitted data gets corrupted resulting in bit errors on the data link.

The better choice for a laser at higher speeds is a laser with a relaxation oscillation. This oscillation is at a much higher frequency than the self-pulsation laser. If the relaxation oscillation lasts through the maximum laser bit-on time (5 bits), the laser will still have all the coherence control and model noise control of a self- pulsation laser. The maximum run length of the data used in the data link is five when the 8b/10b encoding scheme is used as stated in Fibre Channel. When the laser in modulated, the relaxation oscillation will cause a slight wavelength shift in the transmitted laser output. This laser shift will lower the coherence length of the laser allowing better error rates on fibers with mode selective loss.

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