Patent ID: 7742513

Claim:
A fiber laser modulation method for modulating a pump light as an input light to an amplifying optical fiber to output a predetermined output light comprising the steps of: forming a pattern of said input light based on a pattern signal in a power level of four phases including a fixed level of a low powered phase, a fixed rising rate of a power rising phase, the power rising phase lasting 10 micro seconds or more, a fixed level of a high power phase and a fixed decreasing rate of a power decreasing phase; setting a power level of said high power phase as a predetermined high power level such that said output light is determined to match with a predetermined required power level; setting a power level of said low powered phase so as to be greater than zero and such that a predetermined low power level is determined that said output light is equal to or less than a predetermined threshold; raising the power level of said power rising phase between said low power level and said high power level in a predetermined rising rate; and decreasing the power level of said power decreasing phase between said high power level and said low power level in a predetermined decreasing rate to produce a rectangular pulsed light without a surge pulse.