Method and apparatus for controlling signal power level in free space communication

A method for controlling the power level of a laser signal in free space communication, said method comprising:

• transmitting, by a communication terminal, an output laser beam into free space;
• receiving, by said communication terminal, at least one signal through a channel that is not free space laser based, said at least one signal representing the power of said output laser beam measured at a distance and at different times;
• determining, by said communication terminal, whether a drop in the power of said output laser beam measured at said distance is due to blockage based on said at least one signal;
• increasing the power level of said output laser beam to a desired level if the power drop is determined not to be due to blockage;
• and
• lowering the power of said output laser beam to a predetermined level if the power drop is determined to be due blockage.

A terminal controlling the power level of a laser signal in free space communication, said terminal comprising:

• a transmitter arranged to transmit an output laser beam into free space;
• a receiver arranged to receive at least one signal through a channel that is not free space laser based, said at least one signal representing the power of said output beam measured at a distance and at different times;
• and
• a controller operatively connected to said transmitter and receiver, said controller determining whether a drop in the power of said output laser beam measured at said distance is due to atmospheric effects based on said at least one signal, said controller increasing the power level of said output laser beam to a desired level if the power drop is determined to be due to atmospheric effects, and said controller lowering the power of said output laser beam to a predetermined level if the power drop is determined not to be due to atmospheric effects.

A terminal controlling the power level of a laser signal in free space communication, said terminal comprising:

• a transmitter arranged to transmit an output laser beam into free space;
• a receiver arranged to receive at least one signal through a channel that is not free space laser based, said at least one signal representing the power of said output beam measured at a distance and at different times;
• and
• a controller operatively connected to said transmitter and receiver, said controller determining whether a drop in the power of said output laser beam measured at said distance is due to blockage based on said at least one signal, said controller increasing the power level of said output laser beam to a desired level if the power drop is determined not to be due to blockage, and said controller lowering the power of said output laser beam to a predetermined level if the power drop is determined to be due to blockage.