Sohrab Modi


Lasers have proved their reliability in high speed communications through fibre optics. The disadvantage with fibre optics is the high cost and the need for a cable to connect the sender to the receivers, hence making it impractical to have fibre optic cables over large distances. The move today is to communicate between points with a free space laser ( ie. a beam unbounded by cables). Semi conductor lasers as used in fibre optic cables are generally not strong enough to communicate over very large distances. Hence a high power laser is used with a modulation technique to transmit this data across. This thesis demonstrates the use of a Helium Neon laser to communicate between two Macintosh computers. Bit signals generated by the Sender are converted to laser pulses with the help of crystals. These pulses are again regenerated as bit signals at the receiver.This complete hardware interface of the Macintosh to the laser was designed and built for this thesis. The Software Protocol written for this thesis is similar to the sliding window protocol used by the ISO reference model. The protocol has been modified to handle high speed transmissions. The windowing environment, has been set up with pull down menu and submenu systems. Dialog boxes generate responses to errors. Disturbances in the beam result in generation of Nacks and the retransmission of bad buffers.

Library of Congress Subject Headings

Laser communication systems--Design; Computer networks--Design; Macintosh (Computer); High power lasers

Publication Date


Document Type


Student Type


Department, Program, or Center

Computer Science (GCCIS)


Jodoin, Ronald

Advisor/Committee Member

Kaminsky, Alan


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