Optical Communication in Free Space

Overview

Forum Link http://www.knoxvillehackerspace.com/phpbb/viewtopic.php?f=6&t=13

Milestones

Range

• Demonstrate point to point communications across a room with Class IIIa lasers and no receiver optics
• Demonstrate point to point communications across a field with Class IIIa lasers and receiver optics present
• Determine distance limitations of point to point communications using Class IIIa lasers
• Procure Class IIIb lasers and necessary protective gear and attempt longer range communications

Data Transfer

Half Duplex

• Go/No Go with simple breadboard circuit
• Simple voice communication with modulator and amplifier circuits
• High speed network communications

Full Duplex

• Go/No Go with simple breadboard circuit
• Simple voice communication with modulator and amplifier circuits
• High speed network communications

Optics

Transmitter

LEDs

LEDs have been demonstrated

Lasers

The potential advantage of using a commercial laser pointer over over an optically enhanced LED is the lack of the additional optics assembly.

A 5 mW green laser pointer is available from http://www.optotronics.com/green-laser-pointers.php with very good beam properties Beam divergence: <1.2 mrad Beam diameter: <1.5 mm

• Add equations for divergence and maybe wolfram alpha application for calculations

• Calculate power density and compare with RONJA results

Legal & Safety

Code of Federal Regulations Title 21 Section 1040 [1]

OSHA Technical Manual Section III Chapter 6 Laser Hazards [2]

ANSI Z136.1 (2007) - Safe Use of Lasers

ANSI Z136.6 (2005) - Safe Use Of Lasers Outdoors

http://en.wikipedia.org/wiki/Laser_safety

External Links

RONJA (Reasonable Optical Near Joint Access) Project Homepage http://ronja.twibright.com/

http://en.wikipedia.org/wiki/RONJA

http://members.misty.com/don/laserfaq.htm

http://www.repairfaq.org/sam/laserdps.htm

http://captain.haddock.8m.com/laser/laser1.html

http://en.wikipedia.org/wiki/Free-space_optical_communication