In this work, we demonstrated a compact Q-switched erbium-doped fiber laser capable of generating high-energy pulses using a newly developed multiwall carbon nanotube (CNT) polyvinyl alcohol (PVA) thin film based saturable absorber. Q-switched pulse operation is obtained by sandwiching the thin film between two fiber ferrules forming a saturable absorber. A saturable absorber with 1.25 wt. % of PVA concentration shows a consistency in generating pulsed laser with a good range of tunable repetition rate, shortest pulse width, and produces a high pulse energy and peak power. The pulse train generated has a maximum repetition rate of 29.9 kHz with a corresponding pulse width of 3.49 μs as a function of maximum pump power of 32.15 mW. The maximum average output power of the Q-switched fiber laser system is 1.49 mW, which translates to a pulse energy of 49.8 nJ. The proposed method of multiwall CNT/PVA thin film fabrication is low in cost and involves uncomplicated processes.

We demonstrate two flat plateaus and the low-noise spectrum of supercontinuum generation (SCG) in a highly nonlinear fiber (HNLF), injected by an amplified picosecond pulse seed of a carbon nanotube-based passively mode locked erbium-doped fiber laser. A broad spectrum of width approximately 1090 nm spanning the range 1130-2220 nm is obtained and the pulse width is compressed to the shorter duration of 70 fs. Variations of the injected peak power up to 33.78 kW into the HNLF are compared and the broad spectrum SCG profiles slightly expand for each of the injected peak powers. This straightforward configuration of SCG offers low output power and ultra-narrow femtosecond pulse width. The results facilitate the development of all fiber time-domain spectroscopy systems based on the photoconductive antenna technique.

No abstract

A means of supercontinuum (SC) generation is proposed and demonstrated, using femtosecond mode-locked pulses with sub-megahertz repetition rate based on the nonlinear polarization rotation technique. Total cavity length is approximately 522 m, which includes an additional 500 m single mode fiber (SMF) and the fundamental repetition rate obtained is 404.5 kHz. The mode-locked spectrum has a central wavelength of approximately 1600 nm and a 3 dB bandwidth of 16 nm, which falls within the L-band region. The threshold power for the mode-locked operation is achieved at approximately 52 mW. At pump power of 74 mW, the measured pulse width, pulse energy, and average Find more related documents in Scopus based on:

The optical effects of laser irradiation on whole human blood were studied. The normal blood samples were taken from healthy persons and the blood samples were exposed to laser beam. Three wavelengths of continuous wave (CW) for diode pumped solid state lasers (DPSSL S) were used to irradiate the blood samples. The wavelengths are (632 nm, 532 nm,473nm and405 nm ) and output varied between ( 3.9, 50,20 and 4.5) mW respectively. The laser exposure time fixed between (5 and 10 ) min for each wavelength. Laser radiation has a great role in the absorption properties of the normal human blood after being compered with absorption spectrum of a non-irradiated sample.