Combining optical injection and polarization-rotated optical feedback in a semiconductor laser can induce self-referenced periodic output that is widely tunable by simply varying the dc-bias points ...of the system's master and slave lasers. We observed a feedback-induced reduction of the fundamental period-one oscillation linewidth by more than two orders of magnitude relative to the injection-only case. Performance was found to be negatively affected by the interference between the external injection signal and the residual feedback in the same polarization. The nonlinear dynamics of the optically injected semiconductor laser can be used to minimize sensitivity to fluctuations in the operating points. However, the use of the nonlinear dynamics at high oscillation frequencies is limited by the decreasing strength of the interaction between the circulating intracavity optical field and the carrier density.
A delay differential equation model of a passively mode-locked two-section quantum-dot laser reveals pulse asymmetry that is experimentally confirmed through direct electric-field measurements using ...frequency-resolved optical gating. This finding indicates that conventional autocorrelators, which obscure the underlying pulse structure due to the symmetry inherent in autocorrelation, are of limited utility in the characterization of these lasers.
A highly tunable millimeter-wave subcarrier signal is generated by optically injecting a Fabry-Perot semiconductor laser. The optically injected light, which enables microwave subcarrier frequencies ...well beyond the injected laser's free-running relaxation-oscillation frequency, is then on-off keyed by direct-current (dc) modulation of the injected slave laser. Adjustment of the subcarrier frequency is easily accomplished by changing either the dc bias current and/or junction temperature of the injected slave or the injecting master laser. In this paper, we theoretically and experimentally investigate the purity of the modulated microwave subcarrier. The generated microwave signal was then transmitted over 50 km of single-mode fiber, demonstrating the applicability of a directly modulated slave laser optically injected into the period-one state for radio-over-fiber applications.
Through a detailed characterization of thermally induced output power degradation it is possible to use junction heating as a tool to resolve thermal interfaces on mus timescales using a single-shot ...characterization technique. In this work, the deleterious effect junction heating has on the optical output power of a laser array is characterized and then used to infer the time-dependent junction temperature in response to current pulses of varying widths. The extracted parameters are also used numerically to model the laser as a temperature-dependent heat source for thermal simulations. This treatment allows realistic packaging and emitter-placement studies to be parametrically performed by incorporating the relationship between temperature and output power/efficiency for each emitter. In this respect, once the temperature behavior of a single emitter is quantified, the operating temperature and output power performance can be accurately predicted for any realistic physical arrangement of laser array and packaging. The experimental method presented in this work is also compared to other techniques and numerical simulations using the nonlinear heat source; this demonstrates the utility of this approach and the convenience of using easily measured parameters in thermal simulations.
A high-repetition-rate ytterbium fiber laser, harmonically mode-locked using a phase modulator, is investigated experimentally, numerically, and analytically. Experimental results agree well with ...numerical simulations using the measured parameter values. By employing a few approximations, our model is cast in terms of a Ginzberg-Landau equation. This equation has known analytic solutions that agree well with the results of the full model in the appropriate limit. Pulse stability is also investigated numerically with an emphasis on the role of third-order dispersion.
Large-signal direct-modulation of a diode laser optically-injected into period-one operation is shown to produce an on-off keyed microwave signal. The signal is highly tunable and transmitted over 50 ...km, suitable for radio-over-fiber applications.
A semi-analytic tool is developed for investigating pulse dynamics in mode-locked lasers. It provides a set of rate equations for pulse energy, width, and chirp, whose solutions predict how these ...pulse parameters evolve from one round trip to the next and how they approach their final steady-state values. An actively mode-locked laser is investigated using this technique and the results are in excellent agreement with numerical simulations and previous analytical studies.
Power-penalty measurements on two Si Mach-Zehnder modulator designs, each compatible with standard CMOS processing, were performed. The results highlight the power penalty and bandwidth advantages of ...the traveling-wave electrode design over a push-pull single-electrode design.
The transient response of a directly modulated injection-locked semiconductor laser operated in the period-one state is analyzed theoretically and verified experimentally. The results illustrate the ...limits and stability properties of the modulated microwave subcarrier frequency.
Combining optical injection and polarization-rotated optical feedback in a semiconductor laser can induce self-referenced periodic output that is widely tunable by simply varying the dc-bias points ...of the master and slave lasers. We observed feedback-induced reduction of the pulsation peak linewidth by more than two orders of magnitude relative to the injection-only case. The nonlinear dynamics of the optically injected semiconductor laser can be used to minimize sensitivity to fluctuations in the operating points. Performance is negatively affected by interference between the external injection signal and residual feedback in the same polarization.
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