Guanghao Zhu

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We study and demonstrate the technique of simultaneous spatial and temporal focusing of femtosecond pulses, with the aim to improve the signal-to-background ratio in multiphoton imaging. This concept is realized by spatially separating spectral components of pulses into a "rainbow beam" and recombining these components only at the spatial focus of the(More)
We show theoretically and experimentally that simultaneous spatial and temporal focusing can scan the temporal focal plane axially by adjusting the group velocity dispersion in the excitation beam path. When the group velocity dispersion is small, the pulse width at the temporal focal plane is transform-limited, and the amount of shift depends linearly upon(More)
We demonstrate a simple, all-fiber technique for removing nonlinear phase due to self-phase modulation in fiber-based chirped-pulse amplification (CPA) systems. Using a LiNbO3 electro-optic phase modulator to emulate a negative nonlinear index of refraction, we are able to remove 1.0 pi rad of self-phase modulation acquired by pulses during amplification(More)
In this paper, we demonstrate clock recovery from a patterned optical-time-division-multiplexed (OTDM) return-to-zero (RZ) data stream. A cascaded LiNbO3 Mach-Zehnder modulator is employed as an efficient optical-electrical mixer. A phase-locked-loop (PLL) is used to lock the cross-correlation component between the optical signal and a local oscillating(More)
We experimentally demonstrate that the stability of cw and mode-locked erbium-doped fiber ring lasers can be improved significantly with a semiconductor optical amplifier (SOA) inside the cavity. The fast saturable gain of the SOA suppresses significantly the self-pulsing that is due to ion pairs in the erbium-doped fiber, which acts as a saturable(More)
We report the generation of an 80 Gbit/s pulse train by an eighth-order rational harmonic mode-locking technique. Equalized pulse-train amplitude is achieved by proper adjustment of the dc bias point and the 10 GHz modulation strength applied to the cavity-loss modulator. A numerical model is developed to simulate the properties of the generated 80 Gbit/s(More)
We demonstrate simultaneous stabilized operation of a mode locked ring fiber laser at two wavelengths. At one of the wavelengths the mode locked operation is at 10 GHz and it is at 40 GHz at the second wavelength. The laser has an intracavity LiNbO3 modulator driven at 10 GHz. The 40 GHz pulses are obtained by rational harmonic mode locking. Pulses with(More)
We demonstrate the removal of 2pi radians of self-phase modulation (SPM) in a fiber-based chirped pulse amplification (CPA) system. Compensation of SPM distortion is achieved in the time domain by using a LiNbO(3) electro-optic phase modulator to emulate a negative nonlinear index of refraction. By synthesizing the drive waveform to the phase modulators(More)
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