We numerically investigate the nonlinear dynamic properties of an exclusive excited-state (ES) emission quantum dot (QD) laser under optical injection. The results show that, under suitable injection parameters, the ES-QD laser can exhibit rich nonlinear dynamical behaviors, such as injection locking (IL), period one (P1), period two (P2), multi-period (MP), and chaotic pulsation (CP). Through mapping these dynamic states in the parameter space of the frequency detuning and the injection coefficient, it can be found that the IL occupies a wide region and the dynamic evolution routes appear in multiple forms. Via permutation entropy (PE) calculation to quantify the complexity of the CP state, the parameter range for acquiring the chaos with high complexity can be determined. Moreover, the influence of the linewidth enhancement factor (LEF) on the dynamical state of the ES-QD laser is analyzed. With the increase of the LEF value, the chaotic area shrinks (expands) in the negative (positive) frequency detuning region, and the IL region gradually shifts towards the negative frequency detuning.

We propose and demonstrate experimentally a scheme for simultaneously generating multi-channel broadband chaotic signals based on two unidirectionally coupled weak-resonant-cavity Fabry-Perot laser diodes (WRC-FPLDs) with almost the same mode interval, where one WRC-FPLD is utilized as master WRC-FPLD (M-WRC-FPLD) and the other is used as slave WRC-FPLD (S-WRC-FPLD). Under the optical injection from the M-WRC-FPLD with suitable injection parameters, multiple longitudinal modes of the S-WRC-FPLD can be simultaneously driven into chaotic states, which can provide multi-channel chaotic signals. Via a tunable optical filter, we inspect the performances of 9-channel chaotic signals, the results show that the chaotic bandwidths are within the range of 8~15 GHz for all the 9-channel chaotic signals. Furthermore, the influences of the injection power and frequency detuning on the performances of the chaotic output from one of the channels are also analyzed.

Polarization switching (PS) and polarization bistability (PB) characteristics of a 1550 nm vertical-cavity surface-emitting laser (VCSEL) subject to orthogonal optical injection (OOI) with time-varying injection power are experimentally investigated for the first time. To implement the optical injection, a Mach-Zehnder modulator (MZM) modulated by a triangular radio wave is adopted, and the influences of some typical parameters on the performances of PS and PB are analyzed. Under suitable operation conditions, PB in the VCSEL subject to OOI with time-varying injection power can be observed only for the input power P0 of MZM locating within a determined range, and the width of hysteresis loop gradually decreases with the increase of P0 from the minimum P0,min to the maximum P0,max. Under different frequency detuning between the injection light and the X polarization mode of the VCSEL, the determined ranges of P0 required for PB are different. With the variation of from a negative value to a positive value, both P0,min and P0,max present a trend of decrease first and then increase. Additionally, with the increase of the modulation frequency, the hysteresis loop width firstly increases rapidly and then gradually tends saturation.