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ABSTRACT: We demonstrate 10-GHz microwave signal generation from a free-running
mode-locked Er-fiber laser with 1.5 fs absolute rms timing jitter integrated
from 1 kHz to 5 GHz (Nyquist frequency) offset frequency. In the 10 kHz - 10
MHz integration bandwidth typically used for microwave generators, the rms
integrated jitter is 0.49 fs. The Er-fiber laser is operated in the
stretched-pulse regime at close-to-zero dispersion to minimize the intrinsic
phase noise from the laser. In order to mitigate the excess phase noise in the
optical-to-electronic conversion process, we synchronize a low-noise
voltage-controlled oscillator to the fiber laser using a fiber
Sagnac-loop-based optical-microwave phase detector. This result shows that one
can generate sub-femtosecond-level jitter microwave signals from free-running
mode-locked fiber lasers and commercially available dielectric resonator
oscillators without stabilized optical references.
02/2013;
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ABSTRACT: We characterize the timing jitter and intensity noise of an 80-MHz soliton Er-fiber laser mode-locked by a fiber taper carbon nanotube saturable absorber (ft-CNT-SA) up to the Nyquist frequency. The measured rms timing jitter is 3.0 fs (11.0 fs) integrated from 10 kHz (1 kHz) to 40 MHz offset frequency. The measured rms relative intensity noise (RIN) is 0.069% (0.021%) integrated from 10 Hz to 40 MHz (1 MHz) offset frequency. We identify that the resulting timing jitter is dominated by the Gordon-Haus jitter originated from the negative dispersion necessary for soliton mode-locking with a slow saturable absorber.
Optics Express 12/2012; 20(28):29524-30. · 3.59 Impact Factor
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ABSTRACT: We synchronize an 8.06 GHz microwave signal from a voltage-controlled oscillator with an optical pulse train from a 77.5 MHz mode-locked Er-fiber laser using a fiber-based optical-microwave phase detector. The residual phase noise between the optical pulse train and the synchronized microwave signal is -133 dBc/Hz (-154 dBc/Hz) at 1 Hz (5 kHz) offset frequency, which results in 838 as integrated rms timing jitter [1 Hz-1 MHz]. The long-term residual phase drift is 847 as (rms) measured over 2 h, which reaches 4×10(-19) fractional frequency instability at 1800 s averaging time. This method has a potential to provide both subfemtosecond-level short-term phase noise and long-term phase stability in microwave extraction from mode-locked fiber lasers.
Optics Letters 07/2012; 37(14):2958-60. · 3.40 Impact Factor
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ABSTRACT: We synchronize a 8.06-GHz microwave signal from a voltage-controlled
oscillator with an optical pulse train from a 77.5- MHz mode-locked Er-fiber
laser using a fiber-based optical-microwave phase detector. The residual phase
noise between the optical pulse train and the synchronized microwave signal is
-133 dBc/Hz (-154 dBc/Hz) at 1 Hz (5 kHz) offset frequency, which results in
838 as integrated rms timing jitter [1 Hz - 1 MHz]. The long-term residual
phase drift is 847 as (rms) measured over 2 hours, which reaches
4\times10^{-19} fractional frequency instability at 1800 s averaging time. This
method has a potential to provide both sub-fs-level short-term phase noise and
long-term phase stability in microwave extraction from mode-locked fiber
lasers.
06/2012;
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ABSTRACT: We demonstrate sub-100-as timing jitter optical pulse trains generated from free-running, 77.6 MHz repetition-rate, mode-locked Er-fiber lasers. At -0.002(±0.001) ps2 net cavity dispersion, the rms timing jitter is 70 as (224 as) integrated from 10 kHz (1 kHz) to 38.8 MHz offset frequency, when measured by a 24 as resolution balanced optical cross correlator. To our knowledge, this result corresponds to the lowest rms timing jitter measured from any mode-locked fiber lasers so far. The measured result also agrees fairly well with the Namiki-Haus analytic model of quantum-limited timing jitter in stretched-pulse fiber lasers.
Optics Letters 11/2011; 36(22):4443-5. · 3.40 Impact Factor
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ABSTRACT: We demonstrate ultra-low timing jitter optical pulse trains from free-running, 80 MHz repetition rate, mode-locked Yb-fiber lasers. Timing jitter of various mode-locking conditions at close-to-zero intracavity dispersion (-0.004 to +0.002 ps(2) range at 1040 nm center wavelength) is characterized using a sub-20-attosecond-resolution balanced optical cross-correlation method. The measured lowest rms timing jitter is 175 attoseconds when integrated from 10 kHz to 40 MHz (Nyquist frequency) offset frequency range, which corresponds to the record-low timing jitter from free-running mode-locked fiber lasers so far. We also experimentally found the mode-locking conditions of fiber lasers where both ultra-low timing jitter and relative intensity noise can be achieved.
Optics Express 07/2011; 19(15):14518-25. · 3.59 Impact Factor
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ABSTRACT: We investigate the high-frequency timing jitter spectral density of mode-locked fiber lasers in different mode-locked regimes. Quantum-noise-limited timing jitter spectra of mode-locked-regime-switchable Yb fiber lasers are measured up to the Nyquist frequency with sub-100-as resolution. The integrated rms timing jitter of soliton, stretched-pulse, and self-similar Yb fiber lasers is measured to be 1.8, 1.1, and 2.9 fs, respectively, when integrated from 10 kHz to 40 MHz. The distinct behavior of jitter spectral density related to pulse formation mechanisms is revealed experimentally for the first time.
Optics Letters 05/2011; 36(10):1761-3. · 3.40 Impact Factor
