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Star Fiber Network With Links Consisting of Short Wave (.8u) And Long Wave (1.3u) Light Sources

IP.com Disclosure Number: IPCOM000100962D
Original Publication Date: 1990-Jun-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 3 page(s) / 89K

Publishing Venue

IBM

Related People

Larsen, TA: AUTHOR

Abstract

Disclosed is a method to allow fiber-optic links utilizing short wave (SW) or .8 micron (u) and long wave (LW) or 1.3 micron (u) light sources to communicate with each other in a common Star network.

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This is the abbreviated version, containing approximately 52% of the total text.

Star Fiber Network With Links Consisting of Short Wave (.8u) And Long Wave (1.3u) Light Sources

       Disclosed is a method to allow fiber-optic links
utilizing short wave (SW) or .8 micron (u) and long wave (LW) or 1.3
micron (u) light sources to communicate with each other in a common
Star network.

      Normally, links utilizing SW (.8u) light sources have detectors
(Si or GaAs) which are sensitive to .8u and NOT 1.3u. Similarly,
links with 1.3u light sources have light detectors only sensitive to
1.3u and not .8u.  In addition, these links normally only have
adequate optical power to communicate as point-to-point links.

      A Star network which enables the two types of links to
communicate with each other is illustrated in Figs. 1 and 2. The
receivers contain photodetectors (Ra,Rb,Rc) known as
'dual-wavelength' detectors which detect .8u and 1.3u light with
similar optical sensitivity. These photodetectors are now available
commercially. They are fabricated with InGaAsP/InP structure with the
light entering the top surface of device (vs. the back of substrate
as is the case for the typical long wave detector).

      The receiver function contains the standard amplifiers, phase-
locked loop, etc. as any typical link.  The function of the control
logic is to select which one of the received signals will be
forwarded to the transmitter function. Most applications would likely
use token passing and thereby under normal operation would not need
the control logic function. In case of collision occurrences, i.e.,
using a form of CSMA/CD (Carrier-Sense Multiple-Access with
Collision-Detection), the control logic will select which input
signal will be transmitted to all links via the optical splitter.

      As mentioned above, the links illustrated are...