Determining the time–frequency parameters of low-power bright picosecond optical pulses by using the interferometric technique

Characterization of the train-average time–frequency parameters inherent in the low-power picosecond optical pulses generated by the actively mode-locked semiconductor laser with an external single-mode fiber cavity

“…An approximate estimation of the pulse duration is also correct, if the frequency chirp is sufficiently small [5]. Here, we use an opportunity [3] of providing experimental conditions, under which the train-average auto-correlation function of the field-strength can serve as a source of exact and reliable information on the average values of both duration and frequency chirp of a low-power optical pulses traveling in high-repetitionrate trains. As usually, let us proceed from the assumption that all pulses in a train are identical pulses with a Gaussian envelope, see Eq.…”

“…Once the pulse frequency chirp b 0 is determined, one can use formula (11) to calculate the pulse duration T by using 0 and b = b 0 . For the supplementary electronically controlled optical component, one can propose exploiting a specific device based on an InGaAsP/InP single-mode traveling-wave semiconductor heterolaser, which is quite similar to a saturableabsorber laser with the clarified facets [3,8].…”

“…Measuring the time-frequency parameters of optical pulses was carried out exploiting the interferometric technique described in [3]. At first, our experimental studies have demonstrated that within mode-locking a single-mode InGaAsP-laser heterostructure at a threshold of self-excitation (practically, it was realized at a pump current of about 50 mA), only a spike-mode free oscillation regime had been observed with an individual spike width of about 0.7-0.9 ps.…”

“…This approach uses the joint Wigner time-frequency distributions [2], which can be found for this regime due to involving a novel original interferometric technique [3]. In so doing, the modified scanning Michelson interferometer was chosen for shaping the field-strength autocorrelation functions peculiar to the pulsed infrared light radiation.…”

Applying the joint Wigner time-frequency distribution to characterization of ultra-short optical dissipative solitary pulses in the actively mode-locked semiconductor laser with an external single-mode fiber cavity

“…For these lasers, we analyze non-conventional regimes of the active mode-locking, which are connected with injecting various modulating signals and appearing specific composite states of a multi-pulse active mode-locking. Then, our approach uses the joint Wigner time-frequency distribution, which can be found due to involving the recently developed interferometric technique 1 . In so doing, the modified scanning Michelson interferometer was exploited for shaping the field-strength auto-correlation functions peculiar to the above-mentioned types of pulsed light radiation.…”