Square-wave pulse with ultra-wide tuning range in a passively mode-locked fiber laser

Abstract

We report the generation of ultrawide tunable square-wave pulse in an erbium-doped mode-locked fiber laser. The pulse width can be tuned in an ultrawide range of more than 1700 ns by simply increasing the pump power. The pulse-width tuning is 5.1 ns/mW. To the best of our knowledge, this is the widest pulse-width tuning range of any square-wave pulse in an all-fiber passively mode-locked fiber laser. Experimental results show that the fiber nonlinearity plays an important role in the tuning range of the output pulse width. The high nonlinearity helps to increase the tuning range of the pulse width.

Tuning the period of square-wave oscillations for delay-coupled optoelectronic systems

“…(59) for q = 1 as function of χ , where χ is changed by increasing P γ 2 while the offset phase is kept constant at = π/4. For small values of χ , the only stationary solution of the map is the fixed point x * = 0, which corresponds to the zero solution in (14). Increasing χ , the zero solution becomes unstable and at χ = 1, as expected from the linear stability analysis, one encounters for offset phase = 0.3π and 0.35π , respectively.…”

“…Asymmetric square waves with a period close to but longer than twice the coupling delay time have also been reported in mutually coupled EELs, in a scheme where the TE mode of each laser is injected into the TM mode of the other laser [10,11]. Moreover, square-wave oscillations have been investigated for vertical-cavity surface-emitting lasers [6,12,15] subject to XPR, semiconductor ring lasers subject to a delayed optical feedback [13], optoelectronic oscillators (OEOs) [16], and mode-locked fiber lasers [14]. Other studies on polarized optical feedback have been proposed in [17,18].…”

“…The generation of tunable pulsating dynamics has been studied over the past few years [6][7][8][9][10][11][12][13][14], motivated by new applications such as optical clocks [7] and other binary logical applications, generation of stable microwave signals, or optical sensing [8]. In particular, stable square waves oscillating in antiphase have been observed in the intensities emitted in each of the polarization directions in edge-emitting diode lasers (EELs) subject to crossed-polarization reinjection (XPR).…”

Square-wave oscillations in a semiconductor ring laser subject to counter-directional delayed mutual feedback

“…SW optical signals are needed as clocks in signal processing and communication systems [13][14][15][16][17][18][19][20][21][22][23]. Utilizing external laser sources, SW generation has been investigated based on chromatic dispersion of mode-locked pulses, bistabilities in semiconductor optical amplifiers, and nonlinearities in optoelectronic oscillators [19][20][21][22].…”

“…Utilizing external laser sources, SW generation has been investigated based on chromatic dispersion of mode-locked pulses, bistabilities in semiconductor optical amplifiers, and nonlinearities in optoelectronic oscillators [19][20][21][22]. SW generation has also been generated directly on the output signal of a laser source by polarization-switching in edge-emitting lasers [13][14][15] and in vertical-cavity surface emitting lasers [16][17][18].…”