Luxeons and low-light detection: Turner, Groth & Long (2
Posted: Tue Jul 08, 2008 2:05 am
The .pdf text attached here was written by Clint Turner (KA7OEI), Michael Groth (VK7MJ) and myself (Chris Long VK3AML). The title "Dollars Versus Decibels" was chosen to describe the way in which we had to balance costs against communication system benefits on the design of a long-distance (150 km+) atmospheric optical communication outfit. The paper was presented at the San Jose (Silicon Valley, California) conference "Photonics West 2008" by Chris Long VK3AML on 21 January 2008.
The most important conclusion that we reached was that non-coherent beams present considerable practical advantages over coherent (laser) beams for long-distance optical comms. work. The reasons for this - principally related to atmospheric turbulence and the loss of wave-front coherence - are discussed at length in the .pdf paper, which was published by the SPIE (Society Of Photometric Instrumentation Engineers).
The principles that we use for low level detection and Luxeon modulation could gainfully be applied to NBTV systems using mechanical scanners.
Several parts of Clint Turner's website are particularly pertinent for users of the new high-output Luxeon sources:
(1) Linear Luxeon modulation: http://www.modulatedlight.org/optical_c ... lator.html
(2) Luxeon overcurrent protection:
http://www.modulatedlight.org/optical_c ... ction.html
(3) Sources for lenses and optical components, esp. mail order over Internet:
http://www.modulatedlight.org/optical_c ... urces.html
In addition, these pages of my own authorship are relevant:
(4) Discussion on advantages of Luxeon sources for modulation:
http://www.modulatedlight.org/Modulated ... uxeon.html
(5) On broadband transimpedance photodiode amplifiers:
http://www.modulatedlight.org/Modulated ... ghtrx.html
We would welcome comments, additions or corrections to these various papers and postings.
- Chris Long VK3AML (for Clint Turner KA7OEI, Mike Groth VK7MJ, and himself).
The most important conclusion that we reached was that non-coherent beams present considerable practical advantages over coherent (laser) beams for long-distance optical comms. work. The reasons for this - principally related to atmospheric turbulence and the loss of wave-front coherence - are discussed at length in the .pdf paper, which was published by the SPIE (Society Of Photometric Instrumentation Engineers).
The principles that we use for low level detection and Luxeon modulation could gainfully be applied to NBTV systems using mechanical scanners.
Several parts of Clint Turner's website are particularly pertinent for users of the new high-output Luxeon sources:
(1) Linear Luxeon modulation: http://www.modulatedlight.org/optical_c ... lator.html
(2) Luxeon overcurrent protection:
http://www.modulatedlight.org/optical_c ... ction.html
(3) Sources for lenses and optical components, esp. mail order over Internet:
http://www.modulatedlight.org/optical_c ... urces.html
In addition, these pages of my own authorship are relevant:
(4) Discussion on advantages of Luxeon sources for modulation:
http://www.modulatedlight.org/Modulated ... uxeon.html
(5) On broadband transimpedance photodiode amplifiers:
http://www.modulatedlight.org/Modulated ... ghtrx.html
We would welcome comments, additions or corrections to these various papers and postings.
- Chris Long VK3AML (for Clint Turner KA7OEI, Mike Groth VK7MJ, and himself).