Professor J. A. Finnegan

by
Prof J. A. Finnegan
Computer Science Department
Oceanview University, KS

The idea of communication by light over long distances (aka optical
tele-communication) is not new.  Fires lit on chains of mountain tops
and ship-to-ship light signaling are examples for early open-space
optical communication systems.  What is new is the ability to divert
the light to flow in fibers.  New is also the fast modulation of light
with information.

The basic idea is simple, using light reduces latency because light
travels fast.

The HISTORY of PHOTONIC COMMUNICATION

The use of light for signaling is a striking example of the true
American innovation.  It dates back about four thousand years to the
native American Indian tribes that used smoke signals to communicate
over long distances (essentially the first packet-based communication).

Thet achieved a data rate of many seconds per bit after an initial
packet pre-amble of about 30 minutes - to start the fire.

There was some independent work on the European continent about a
thousand years later when the Greeks used their shiny shields as
modulators to bounce sun-light to their generals during battle.

After their patent has expired the same idea was copied by the active
sun-collection farms which may be found today in California.

However, this was short-distance communication and quite unreliable
(to be precise, reliable optical communications were short-lived).

Unfortunately, the rate of innovation of light-based signaling in the
Americas was reduced drastically over the next several millenia because
most of the native American Indian engineers were killed by the
settling European engineers in an early example of predatory business
practices.

COMMUNICATION APPLICATIONS

In modern digital binary communication the only symbols are 0 and 1.
Light represents the 1s and 0s are represented by darkness.  In order
to reduce skew it is very important to minimize the disparity between
the speed of light (SoL) and the speed of darkness (SoD).

Since SoL, in vacuum, is the fastest speed that physics allows, SoD