[Laser] SD3084 photodiode

[F1AVYopto at aol.com]

I got from  old laser barcode scanners 3 hybrid photodiodes SD3084 from  SDC. 
These diodes  contains in a TO5 package a very small PIN photodiode (less 
than 1 mm²), a JFET,  a resistor. 
After some  experiments I identified the good wiring and I built a K3PGP RX 
with one of  these old components. 
I am very  surprised because without lenses this receiver has about the same  
sensitivity limit an other K3PGP RX fitted with a 7,5 mm² PIN photodiode  
BPW34 (tested with my adjustable LED beacon at 300 Hz).   
If we  consider the sensitive areas ratio that could mean the SD3084 has  
about 8 dB better SNR than a BPW34. 
I have no  parameter about the SD3084 photodiode. 
Is there  somebody having some information about this  component?  
Yves  F1AVY