Optical comb carrier envelope frequency control using a rotating waveplate frequency shifter
A system for optical comb carrier envelope offset frequency control includes a mode-locked laser and a frequency shifter. The mode-locked laser produces a laser output. The frequency shifter shifts the laser output to produce a frequency shifted laser output based at least in part on one or more control signals. The frequency shifted laser output has a controlled carrier envelope offset frequency. The frequency shifter includes a first polarization converter, a rotating half-wave plate, and a second polarization converter.
1. A system for optical comb carrier envelope offset frequency control, comprising:
a mode-locked laser, wherein the mode-locked laser produces a laser output; and
a frequency shifter, wherein the frequency shifter shifts the laser output to produce a frequency shifted laser output based at least in part on one or more control signals, wherein the frequency shifted laser output comprises a controlled carrier envelope offset frequency, and wherein the frequency shifter comprises a first polarization converter, a rotating half-wave plate, and a second polarization converter.
2. The system of claim 1 , wherein the first polarization converter comprises a quarter-wave plate.
3. The system of claim 1 , wherein the second polarization converter comprises a quarter-wave plate.
4. The system of claim 1 , further comprising:
a beat note generator, wherein a portion of the frequency shifted laser output is used to produce an optical beat note; and
a control signal generator, wherein the control signal generator produces the one or more control signals to control the optical beat note.
5. The system of claim 4 , wherein the one or more control signals control(s) the rotation of the rotating half-wave plate.
6. The system of claim 4 , wherein the optical beat note is converted to an electrical signal using a photodetector.
7. The system of claim 4 , wherein stabilizing the optical beat note comprises controlling the optical beat note frequency to match a reference frequency.
8. The system of claim 7 , wherein the reference frequency comprises the desired comb carrier offset frequency.
9. The system of claim 4 , wherein stabilizing the optical beat note comprises stabilizing a phase-locked loop, wherein the phase-locked loop includes a reference frequency.
10. The system of claim 4 , wherein the control signal comprises a frequency such that the optical beat note is phase locked to a reference frequency.
11. The system of claim 10 , wherein the control signal comprises one or more control voltages for applying one or more electric fields to an electro-optic polarization controller.
12. The system of claim 4 , wherein the beat note generator generates the beat note by determining a frequency difference between the frequency shifted laser output and a frequency doubled version of the frequency shifted laser output.
13. The system of claim 4 , wherein the control signal generator comprises a phase-locked loop.
14. The system of claim 13 , wherein the phase-locked loop is implemented using an analog voltage-controlled oscillator for creating a first control signal.
15. The system of claim 14 , wherein a second phase-locked loop is used to create a second control signal with a specific phase offset to the first control signal.
16. The system of claim 15 , wherein the phase-locked loop is implemented using a direct digital synthesizer or a numerically controlled oscillator.
17. The system of claim 16 , wherein the direct digital synthesizer is controlled using a digital controller implemented using a field programmable gate array.
18. The system of claim 16 , wherein the direct digital synthesizer is implemented using a field programmable gate array.
19. The system of claim 4 , wherein the control signal generator produces a control signal for controlling a pump laser for the mode locked laser.
20. The system of claim 1 , wherein the rotating half-wave plate comprises an electro-optic polarization controller.
21. The system of claim 20 , wherein one or more control signals cause(s) the electro-optic polarization controller to emulate the rotating half-wave plate.
22. The system of claim 20 , wherein the electro-optic polarization controller comprises a Pockels cell.
23. The system of claim 20 , wherein the electro-optic polarization controller comprises a fiber-optic or waveguide polarization controller.
24. A method for optical comb carrier envelope offset frequency control, comprising:
causing, using a processor, production of a mode-locked laser output; and
causing shifting of the laser output to produce a frequency shifted laser output based at least in part on one or more control signals, wherein the frequency shifted laser output comprises a controlled carrier envelope offset frequency, and wherein a frequency shifter for causing shifting of the laser output comprises a first polarization converter, a rotating half-wave plate, and a second polarization converter.
25. A computer program product for optical comb carrier envelope offset frequency control, the computer program product being embodied in a non-transitory computer readable storage medium and comprising computer instructions for:
causing production of a mode-locked laser output; and
causing shifting of the laser output to produce a frequency shifted laser output based at least in part on one or more control signals, wherein the frequency shifted laser output comprises a controlled carrier envelope offset frequency, and wherein a frequency shifter for causing shifting of the laser output comprises a first polarization converter, a rotating half-wave plate, and a second polarization converter.