Repetition frequency control device
View Patent ↗According to the repetition frequency control device, a master laser outputs a master laser light pulse the repetition frequency of which is controlled to a predetermined value. A slave laser outputs a slave laser light pulse. A reference comparator compares a voltage of a 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 measurement comparator compares a 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 phase difference detector detects a phase difference between the output from the reference comparator and the output from the measurement comparator. A loop filter removes a high-frequency component of an output from the phase difference detector.
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.
2. The repetition frequency control device according to claim 1 , wherein the predetermined voltage is a ground electric potential.
3. The repetition frequency control device according to claim 1 , wherein the resonator length of the slave laser changes according to the output from the adder.
4. The repetition frequency control device according to claim 3 , wherein:
the slave laser comprises a piezo element;
the output from the adder is fed to the piezo element; and
the resonator length of the slave laser is changed by extension and contraction of the piezo element.
5. The repetition frequency control device according to claim 1 , comprising:
a photoelectric converter that receives the slave laser light pulse; and
a low-pass filter that removes a high-frequency component of the output from the photoelectric converter.
6. The repetition frequency control device according to claim 1 , wherein the repetition frequency control signal is output from an arbitrary wave generator.
7. The repetition frequency control device according to claim 1 , comprising:
a master-side reference comparator that compares the voltage of the reference electric signal the frequency of which is the predetermined value and the 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.