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Path: brunix!sgiblab!darwin.sura.net!uvaarpa!cv3.cv.nrao.edu!cv3.cv.nrao.edu!browen
From: browen@lyapunov.aoc.nrao.edu (Bruce Rowen)
Subject: IR beacon. The spec sheet
Message-ID: <BROWEN.93Aug31110348@lyapunov.aoc.nrao.edu>
Sender: news@nrao.edu
Organization: National Radio Astronomy Observatory, Socorro NM
Distribution: usa
Date: Tue, 31 Aug 1993 17:03:48 GMT
Lines: 123


Due to popular demand, Here is an abridged translation of the laser
diode spec sheet for the device I used to construct a "mega beacon".


--------8<--(cut here)----------------------------------------------


Laser Diode Laboratories Inc.

Single Heterojunction GaAs Laser Diodes
LD 60 Series

Featuring:
  
	o High efficiency at low drive currents

	o Up to 25 Watts peak power output (yes, 25W)

	o 905 nanometers peak wavelength emission at 25 deg C

	o Operation to 75 deg C

	o Optically centered hermetic coaxial package


	The model LD-60 series diodes are gallium arsenide injection
diodes which emit coherent infrared radiation. The diode is built in
a hetero-junction structure, consisting of three distinct layers:
N-type gallium arsenide, P-type gallium arsenide, and P-type gallium
aluminum arsenide. Recombination occurs in the immediate vicinity of
the gallium arsenide P-type region. The hetero-junction formed at the
interface of the P-type gallium arsenide and P-type gallium aluminum
arsenide serves to confine the injected carriers and also to reduce
reabsorption. As a result of this, threshold is reduced, and power
efficiency correspondingly increased.

	The radiant power output is proportional to the foward current
and the spectrum is in the region of the peak sensitivity of the S-1
photocathode surface and of silicon photodectors.

	The device is hermetically sealed in an optically centered
coaxial package with the 8-32 screw stud the negative terminal. Units
with reversed polarity are available upon request.

	The model LD-60 series diodes are designed for pulse mode
operation. The rise and fall time of the applied current should be
short to minimize junction heating. Care should also be taken not to
exceed the maximum 3 volt reverse voltage rating. Reverse voltages
exceeding 3 volts peak will rapidly degrade the laser's performance.
Suitable pulsers to operate these devices are available from Laser
Diode Laboratories, Inc.


                                  (the one I have $4.95)
                                          ^^^
			     LD-60 LD-61 LD-62 LD-63 LD-65 LD-66 LD-67 LD-68 Units 
----------------------------------------------------------------------------------
Total Pk. Radiant Flux:  Min.  2     1     5     5    10     8    16    16   Watts
at max. rated Ifm. 	 Typ.  2.3   1.5   6     6    12     9.5  20    25   Watts
----------------------------------------------------------------------------------
Max. Pk. Forward Current Ifm. 10    10    20    25    40    40    60    75   Amps
----------------------------------------------------------------------------------
Typ. Threshold Current   Ith . 3     3.5   6     7    10    12    16    18   Amps
----------------------------------------------------------------------------------
Typical Peak	       @Ifm.   5.0   5.0   5.8   6.5   6.7   6.7   7.0   8.0 Volts 
Forward Voltage        @50ma   1.2   1.2   1.2   1.2   1.2   1.2   1.2   1.2 Volts
----------------------------------------------------------------------------------
Emitting Area                3x.08 3x.08 6x.08 6x.08 9x.08 9x.08 16x.08 16x.08 Mils
----------------------------------------------------------------------------------


----------------------------------------------------------------------------------
				Min.		Typical		Max.	Units
----------------------------------------------------------------------------------
Wavelength of Peak Intensity			  904			  nm
----------------------------------------------------------------------------------
Spectral Width @ -3db pts.			    3.5			  nm
----------------------------------------------------------------------------------
Rise Time of Radiant Flux			  <0.5                    ns
 10% to 90% points.      
----------------------------------------------------------------------------------
Pulse Width -3db points @Ifm					200	  ns
----------------------------------------------------------------------------------
Duty Factor @ Ifm						0.1	  %
----------------------------------------------------------------------------------
Storage Temperature		-196				+150      deg C
----------------------------------------------------------------------------------
Operating Temperature		-196				 +75      deg C
----------------------------------------------------------------------------------





Lots of graphs follow (I refuse to reproduce here!) BUT I'll summarize!

Typical peak power output vs. pulse repetition rate:
  rolloff from 100% at 1KHz to 70% at 10KHz (200ns pulse width)
  rolloff from 100% at 1KHz to 95% at 10KHz (100ns pulse width)


Total peak radiant flux vs. peak forward current: (at various temps)
  linear relation with colder temps producing peak flux at a 
  lower forward current
	(@-55C peak flux at 75% peak power)
	(@27C peak flux at 100% peak power)
	(@75C 45% flux at  peak power)


Several graphs on life cycle tests, wavelength spread, power vs. case temp, 
 beam spread (-3db at about +- 10 degrees)

----------------------------8<-(cut here)--------------------------------------------


--
-------------------------------------------------------------------------------
Bruce Rowen 				National Radio Astronomy Observatory
Scientific Programmer				Array Operations Center
browen@aoc.nrao.edu			  P.O. Box O  Socorro, NM   87801
(505)385-7329					     (505)385-7000
-------------------------------------------------------------------------------
