LASER circuit for transmitting voice

The schematic below shows Laser circuit that can be used for transmitting voice signal. Proteus Professional 8 was used for simulation demonstration of modulating a laser with audio signal.

Fig: Laser Circuit Schematic for Audio Modulation

The audio signal is applied to the pin 5 of the LM555 timer and this varying signal modulates the LED(Laser) which is connected Pin 4 and 3 as shown. The circuit is supplied with 12V battery and the switch puts on/off the circuit operation. The resistors and capacitor forms the bias circuit and coupling capacitors.

The audio signal is a real voice signal in .wav format and applied to the circuit using the audio generator part available in the generator palette.The following figure shows how the configuration looks like-

Fig: Audio Generator Configuration

When the simulation is run we can see the LED(laser) blinking and producing blue light in accordance to the input audio signal. This is shown below-

Fig: Simulating the Laser circuit