A photodiode is often described a s a current source in photovoltaic mode. the formula for developing a voltage across a photodiode diode is V = S. P . R
V= v out
S= photodidoe responsivity with wavelength
P= laser/ light power
R= load resistor

What i can't understand is placing a 10k resistor as R instead of a 1k resistor will give me a 10 times increase in voltage. so for the same input light intensity I've just increased my output voltage.........great- but doesn't it violate conservation of energy, where is the catch?