Patent ID: 8718108
Filing Date: 2014-05-06
Classification: H01S

Abstract:
1. A repetition frequency control device comprising: a master laser that outputs a master laser light pulse, the repetition frequency of which is controlled to a predetermined value; a master-side reference comparator that compares a voltage of a reference electric signal, the frequency of which is the predetermined value, and a predetermined voltage with each other, thereby outputting a result thereof; a master-side measurement comparator that compares a voltage of a master-side measurement electric signal having a voltage based on a light intensity of the master laser light pulse, and a frequency of the predetermined value, and the predetermined voltage with each other, thereby outputting a result thereof; a master-side phase difference detector that detects a phase difference between the output from the master-side reference comparator and the output from the master-side measurement comparator; and a master-side loop filter that removes a high-frequency component of an output from the master-side phase difference detector, wherein the repetition frequency of the master laser light pulse changes according to an output from the master-side loop filter; a slave laser that outputs a slave laser light pulse; a slave-side reference comparator that compares a voltage of the reference electric signal, the repetition frequency of which is the predetermined value, and a predetermined voltage with each other, thereby outputting a result thereof; a slave-side measurement comparator that compares the voltage based on a light intensity of the slave laser light pulse and the predetermined voltage with each other, thereby outputting a result thereof; a slave-side phase difference detector that detects a phase difference between the output from the slave-side reference comparator and the output from the slave-side measurement comparator; a slave-side loop filter that removes a high-frequency component of an output from the slave-side phase difference detector; and an adder that adds a repetition frequency control signal to an output from the slave-side loop filter, wherein: the repetition frequency control signal has a constant repetition cycle; and the repetition frequency of the slave laser light pulse changes according to the output from the adder.