Passive repetition-rate stabilization for a mode-locked fiber laser by electro-optic modulation

RF-controlled mode-locking and optoelectronic pulse compressing with distributed selectable wavelengths

Mode-locking in laser cavities has attracted great interest due to its wide range of applications in generating optical frequency combs and ultra-short pulse trains. Here, a mode-locked fiber laser with a distributed selectable wavelength feedback is proposed based on radio frequency maneuverability. The laser is capable of generating transform-limited pulses with a selectable wavelength and repetition rates by interrogating different reflectors through active modulation. Intriguing laser pulses were realized, which can have >930 times width compression ratio compared with the modulation signal and can be selectively locked to reflectors separated in centimeter scale.

High-precision digital optical phase locking for 10-12 W order weak light for a spaceborne gravitational wave interferometer

We developed a digital optical phase-locking loop (DOPLL) for weak light phase locking in spaceborne gravitational wave interferometers (SGWIs). Using the system, we successfully locked the phase of the slave laser to the master laser with the power of only several picowatts, much smaller than the LISA requirement (100 pW). The system does not introduce steady-state errors, and the Bode diagram shows its stability. The out-loop phase noise floor (2.3×10-4 and 5.2×10-4 r a d/H z 1/2) is very close to the shot noise limit. The Allan standard deviation of the heterodyne signal reaches 3.1×10-17 at 1000 s. With the previous automatic locking program designed by other researchers, the results demonstrate that DOPLLs have bright application prospects and can be applied in the transducer of the SGWI.