Improved expression for the time-bandwidth product of picosecond optical pulses from gain-switched semiconductor lasers

Abstract

An improved expression for the time-bandwidth product (DeltatDeltaf) of picosecond optical pulses from gain-switched semiconductor lasers was obtained by a series of numerical simulations based on rate equations without making any assumption for a particular pulse shape and chirp condition. The relation can be expressed by [Equation] as a function of the linewidth-enhancement factor alpha. The influence of the spontaneous emission factor beta on the relation is also examined.

Pulse shortening of gain switched single mode semiconductor lasers using a variable delay interferometer

“…1(d), the spectrum has an asymmetric intensity profile characterized by a peak on the lower frequencies side and a broadened "shoulder" profile on the higher frequencies side. These correspond to the falling and rising edges of the pulse, respectively, as predicted by theory [11,12] and confirmed with experiments [13,14]. According to this, spectral filtering can be used for shaping the pulse edges in the temporal domain.…”

“…1(d). The spectrum is characterized with a quasi-periodic structure which has been reported in previous works on GS lasers both theoretically [11,12] and experimentally [5]. This is understood as the spectral signature of the relaxation oscillations at these gain switching conditions.…”

Time–bandwidth product of chirped sech^2 pulses: application to phase–amplitude-coupling factor measurement

“…1,2 Moreover, experimental evidence suggests that pulses from gainswitched semiconductor lasers have sech 2 rather than Gaussian shapes. 4,5 In this Letter a new formula is derived that, unlike other expressions proposed, 6 is exact for the chirped sech 2 pulse and gives better estimates of the laser's a factor in the large-signal regime than the Gaussian approximation gives.…”

Non-Pulse-Leakage 100-kHz Level, High Beam Quality Industrial Grade Nd:YVO4 Picosecond Amplifier

“…Figure 4a shows the autocorrelation trace of the amplified pulses with the measured width of 16.9 ps at a repetition rate of 500 Hz. The pulse width of the output was slightly broadened compared with that of the seed pulses 11.5 ps, which is mainly caused by the gain narrowing [30,31]. The measured beam quality factor M 2 and near-field beam intensity profile are shown in Figure 4b.…”