Tuesday, July 19, 2016

What's Old is New Again

I remember playing with lasers in the late 60s, we were using them in a laser scanning gyro, an exceptionally accurate and precise mechanism to be used in navigation systems. Mechanical gyros had significant drift and required resetting. The result was in my first paper, co-authored with some pretty bright folks, I was just a tag along as the engineer. Then in the 70s we considered optical inter-satellite links, the 80s we did point to multi-point links, in the 90s I was Chairman of an Israeli company, JOLT, Jerusalem Optical Light Transmission, where we used IR and visible.

Yet whenever you put this stuff in the air with any form of moisture you suffered significant loss.

PCWorld announces another try:

Facebook says it has developed a laser detector that could open the airwaves to new high-speed data communications systems that don't require dedicated spectrum or licenses. The component, disclosed on Tuesday in a scientific journal, comes from the company's Connectivity Lab, which is involved in developing technology that can help spread high-speed Internet to places it currently doesn't reach. Getting Internet signals to new areas is typically done using wireless, because it's much more cost-efficient than running cables to communities outside of urban areas. But traditional wireless comes with speed limitations and requires radio spectrum that often needs to be purchased from the government. Faced with these limitations, engineers have increasingly eyed sending data from point-to-point over laser beams. They don't need any special spectrum or permission, and multiple systems can work in the same area without interfering with each other.

Yep! No license. Never was required. However watch out for water loss and eye damage. Never want one of those pointers poking in your eye.  Most of the above is well known and obvious. It appears however the "new" part is the nature of a distributed receiver. Optical receivers were always a problem. You needed to track a narrow beam, and that was complex. Often we had pigeons sitting on the receiver, just enough stress and strain to off set the beam.

So, all too often the real world comes slamming down on you. One of our biggest problems was the swaying of the old World Trade Center, just enough to lose connections.