Widely Wavelength-tunable Soliton Generation and Few-cycle Pulse Compression with the Use of Dispersion-decreasing Fiber (original) (raw)
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Compact system of wavelength-tunable femtosecond soliton pulse generation using optical fibers
IEEE Photonics Technology Letters, 2000
Using passively mode-locked femtosecond (fs) fiber laser and polarization maintaining fibers, the compact system of wavelength-tunable femtosecond (fs) fundamental soliton pulse generation is realized. The monocolored soliton pulse, not multicolored ones, with the ideal sech 2 shape is generated, and its wavelength can be linearly shifted by varying merely the fiberinput power in the wide wavelength region of 1.56-1.78 m for 75-m fiber. The soliton pulses of less than 200 fs are generated with the high conversion efficiency of 75%-85%. This system can be widely used as a portable and practical wavelength-tunable fs optical pulse sources.
The possibility of the efficient conversion of the frequency of an optical soliton pulse in fibers with length-variable dispersion is physically analyzed and experimentally investigated. The effect is based on the Raman transformation of the frequency of an ultrashort pulse, which can be varied with high efficiency due to the compression mechanism of maintaining a high intensity of the pulse in a medium with monotonically decreasing anomalous dispersion. A smooth rearrangement of the spectrum of the soliton pulse 90 fs in duration in the range 1.58–1.75 µm is demonstrated.
Soliton filtering from a supercontinuum: a tunable femtosecond pulse source
Journal of Physics: Conference Series, 2011
In this article we report experimental results related with the generation of a supercontinuum in a microstructured fiber, from which the soliton with the longest wavelength is filtered out of the continuum and is used to construct a tunable ultrashort pulses source by varying the pump power. Pulses of an 80 fs duration (FWHM) from a Ti:sapphire oscillator were input into a 2 m long fiber to generate the continuum. The duration of the solitons at the fiber output was preserved by using a zero dispersion filtering system, which selected the longest wavelength soliton, while avoiding temporal spreading of the solitons. We present a complete characterization of the filtered pulses that are continuously tunable in the 850-1100 nm range. We also show that the experimental results have a qualitative agreement with theory. An important property of the proposed near-infrared pulsed source is that the soliton pulse energies obtained after filtering are large enough for applications in nonlinear microscopy.
0.78-0.90-μm wavelength-tunable femtosecond soliton pulse generation using photonic crystal fiber
IEEE Photonics Technology Letters, 2000
Compact system of 780-900-nm wavelength tunable femtosecond soliton pulse generation is demonstrated for the first time using fiber laser, periodically poled LiNbO 3 , and photonic crystal fiber (PCF). The wavelength of generated soliton pulse can be shifted almost linearly by varying the fiber input power. The temporal width of the generated soliton pulse is as short as 55 fs. As the results of numerical analysis, it is expected that the wavelength of the soliton pulse is shifted above 1.1 m using much higher power or longer PCF. This system is constructed with almost all the fiber devices and it is compact and useful for practical applications.
Optics Express, 2010
We demonstrated spectral compression of ultrashort soliton pulses in a wide wavelength region based on an adiabatic soliton spectral compression technique using a comb-profile fiber. The comb-profile fiber was carefully designed using numerical analysis and fabricated using a conventional single-mode fiber and a dispersion-shifted fiber. The spectral width of a 200 fs soliton pulse was compressed from 12 to 15 nm to 0.54-0.71 nm in the wavelength region 1620-1850 nm, giving a spectral compression factor of up to 19.8-25.9. Owing to the soliton effect, the side lobe level was suppressed to-19.2 to-9.7 dB.
Optical Review, 2000
We have investigated both experimentally and numerically the characteristics of wavelength tunable femtosecond soliton pulse generation using a pulse width variable fiber laser and two different types of polarization maintaining fibers. The generated soliton shows the feature of the pulsewidth becoming almost constant at -250 fs under any conditions of the pump pulse for 220m fiber. High conversion efiiciency from pump pulse to a generated soliton pulse accounting for as much as 730/0 can be obtained. This efliciency decreases with increase in the input power or wavelength shift. A superior conversion eiliciency and broad wavelength shift can be obtained by using a more shortened pump pulse. In the numerical calculations, it is predicted that under a condition of constant power of pump pulse, the maximum wavelength shift is achieved when the soliton number N is -1.4. The difference of mode field diameter and the group velocity dispersion (GVD) coefficient fi2 affect the wavelength shift and conversion efiiciency. Using the fiber with small mode field diameter and small absolute value of GVD coeflicient fi2, a high conversion efiiciency and large wavelength shift can be obtained.
Tunable, femtosecond soliton generation from amplified continuous-wave diode-laser signals
1990
Solitons with pulse widths as short as 200 fsec have been generated through the preferential amplification of a seed signal from a continuous-wave diode laser by Raman amplification from a mode-locked Nd:YAG laser. The soliton Raman generation process in optical fibers has been fairly comprehensively investigated by several groups, both theoretically 1-4 and experimentally. 4-1 2 Possibly the simplest experimental arrangement is the single-pass generation scheme, 7-9 ' 12 which has been shown to give rise to an expansive spectral continuum
Papers in Physics, 2012
We present a high-speed wavelength tunable photonic crystal fiber-based source capable of generating tunable femtosecond solitons in the infrared region. Through measurements and numerical simulation, we show that both the pulsewidth and the spectral width of the output pulses remain nearly constant over the entire tuning range from 860 to 1160 nm. This remarkable behavior is observed even when pump pulses are heavily chirped (7400 fs 2), which allows to avoid bulky compensation optics, or the use of another fiber, for dispersion compensation usually required by the tuning device.
Generation of tightly compressed solitons with a tunable frequency shift in Raman-free fibers
Optics Letters, 2013
Optimization of the compression of input N-solitons into robust ultra-narrow fundamental solitons, with a tunable up-or downshifted frequency, is proposed in photonic crystal fibers (PCF) free of the Raman effect. Due to the absence of the Raman self-frequency shift, these fundamental solitons continue propagation maintaining the acquired frequency, once separated from the input N-soliton's temporal slot. A universal optimal value of the relative strength of the third-orderdispersion (TOD) is found, providing the strongest compression of the fundamental soliton, is found. It depends only the order of the injected N-soliton. The largest compression degree significantly exceeds the analytical prediction supplied by the Satsuma-Yajima (SY) formula. The mechanism behind this effect, which remains valid in the presence of the selfsteepening, is explained.