Modulating the output power of a laser diode can happen in two ways: by changing the signal input/driving current1,2 or by alternating the continuous wave output after the light is generated. 2 In laser modulation, the current or voltage varies with time to modulate the output signal from the laser. I think you can't change the power. So an optical system "should" be used. (Unlike some pre-build diode modules. Laser modulation is a critical facet of laser technology, allowing for controlled variations in key parameters such as intensity, frequency, or phase. Such control opens the door to a broad range of scientific and commercial applications.