Trip Report 

Attendee:                Alfred Andrawis
Representing:
         SDSU
Travel Dates:
        July 1-5, 2002
Location:
                Cambridge, Massachusetts

The purpose of this trip was two primary activities; the first activity was to attend the Progress in Electromagnetics Research Symposium (PIERS), July 1-5, 2002, Cambridge, Massachusetts.  During the symposium a paper was published and presented entitled "CONNECTOR OFFSET EFFECTS ON BANDWIDTH-DISTANCE PRODUCT OF MULTIMODE FIBER".  This paper reports the successful attempts in extending the bandwidth-distance product as well as reducing the modal noise of multi mode fibers using a simple offset ferrule connector.  The motivation for this research is the introduction of digital television and the increase popularity for Internet services, which are continually increasing the demand for higher data rate transmission on local area networks.  Such high-speed networks are expected to be essential for the NASA centers backbone networks.  This research is conducted jointly between SDSU faculty and a NASA Kennedy Space Center (NASA KSC), FL scientists and engineers (paper abstract is attached).  

The second activity is to meet paper’s co-author (Mr. Huang) to discuss the possibilities for further future research collaboration between NASA KSC and SDSU in the area of Fiber Optic Communications and other related topics.  As a result of these meetings a proposal is in the making addressing the topics mentioned by NASA KSC scientist. 


CONNECTOR OFFSET EFFECTS ON BANDWIDTH-DISTANCE PRODUCT OF MULTIMODE FIBER

 Alfred S. Andrawis
South Dakota State University

Electrical Engineering Department, South Dakota State University, Brookings, SD 57007

Tel: (605) 688-6217, Fax: (605) 688-5880.
E-mail: Alfred_Andrawis@sdstate.edu

 Po Tien Huang
Kennedy Space Center

Mail Code: MM-G1-C, Kennedy Space Center, Florida 32899

Tel: (407) 867-9788, Fax: (407) 867-6344.

E-mail: PoTien.Huang-1@ksc.nasa.gov

 SUMMARY

         The local area network (LAN) market has undergone significant changes over the last few years.  The major motivation of the market transformation is the exponential growth of the data moving across the network.  Recently, the IEEE Gigabit Ethernet Committee completed the Gigabit Ethernet (GbE) standard to meet the explosive demand.  The dominant fiber base used in LANs is multimode fiber (MMF) however, its modal bandwidth imposes an upper limit on the achievable bit rate and link distance.

        Two types of optical modes, meridional ray modes and skewed ray modes, propagate in an overfilled (OFL) MMF.  Mainly, meridional ray modes, as well as low order skewed ray modes limit the modal bandwidth in a MMF.  If these modes are eliminated, MMF bandwidth-distance product improves significantly.

There have been several successful attempts to overcome the OFL bandwidth-distance product limit by selective excitation of only higher order skewed ray modes.

This paper is to explore the possibility of selective excitation of modes using a technique simpler than the ones reported in literature. This technique is expected to be easier to implement than reported attempts.  It consists of SMF-to-MMF lateral offset ferrule connector.  Offset launch condition is controlled such that only higher order modes are selectively excited.  Selective mode excitement results in extending the bandwidth-distance product as well as reducing the modal noise.

A short description of offset ferrule connector will be initially introduced in this paper.  Then, performance test results for eye pattern, Jitter, power loss, bit error rate (BER) and optical power distribution for several connector-offset values will also be presented.


Back to "Trips and Collaboration" SD Personnel and NASA Centers / NASA-related activities website