[Laser] 5 mW lasers & LEDs

[Steve J. Noll]

Been looking at inexpensive lasers & narrow beam LEDs to meet 5 mW ARRL 
contest limit.

eBay "Copper Lasers"
660nm wavelength.Most measure 5 mW output, a few percent 6 mW, and a few 
1 to 4 mW. Some sold as 3V, some 4.5V, and some 5V, but seller says 4.5V 
and 5V are really the same. The all appear to want about 21 mA, give or 
take a milliamp, to give 5 mW output and it's probably best to adjust 
the supply voltage to result in that amount of current. The wire colors 
are not consistent lot to lot, i.e.: some 3V lasers have red and yellow 
leads, some red and blue. Lens housing can be rotated to adjust the beam 
quality which is pretty good especially considering they sell for about 
$18 for 70, or 26 cents each!. Construction appears to be simply a laser 
die and a series resistor. There is no ESD protection, no optical 
feedback power control, etc. Measured 7 to 10 nS rise (35 MHz BW) .

Vishay TLCR5800 622 nm 8-degree beamwidth LED, measured 60 nS rise, 30 
nS fall. 3 mW @ 20 mA, 5 mW @ 38 mA. Projects pattern with dark spot in 
center. About 15 cents.

Optek OVLGS0C8B9 623 nm 8-degree beamwidth LED, measured 30 nS rise 20 
nS fall. 3 mW @ 20 mA, 5 mW @ 37 mA. Projects pattern with dark spot in 
center. About 20 cents.

Avago HLMP-EG08-Y2000 635 nm 8-degree beamwidth, 23 nS rise & fall. 1.5 
mW @ 20 mA, 5 mW @ 100 mA. Good pattern, no dark spot in center. About 
50 cents.

Rise/Falls measured with a First Sensor PS0.25-5-TO52-SI photodiode (0.4 
nS rise) at -32V bias, Tek TDS524A 500 MHz oscilloscope, HP 8004A pulse 
generator (< 1.5 nS.) Powers measured with a calibrated 1 cm photodiode.

73,

*Steve J. Noll, WA6EJO
http://www.qrz.com/db/WA6EJO
http://www.linkedin.com/in/stevejnoll
*