Analysis of an Optically Injected Semiconductor Laser for Microwave Generation

Abstract

Abstract-The nonlinear dynamical period-one oscillation of an optically injected semiconductor laser is investigated analytically. The oscillation is commonly observed when the injection is moderately strong and positively detuned from the Hopf bifurcation boundary. The laser emits continuous-wave optical signal with periodic intensity oscillation. Since the oscillation frequency is widely tunable beyond the relaxation oscillation frequency, the system can be regarded as a high-speed photonic microwave source. In this paper, analytical solution of the oscillation is presented for the first time. By applying a two-wavelength approximation to the rate equations, we obtain mathematical expressions that characterize the oscillation. The analysis explains the physical origin of the periodic intensity oscillation as the beating between two wavelengths, namely, the injected wavelength and the cavity resonance wavelength. As the injection strength increases, the optical gain reduces, the cavity is red-shifted through the antiguidance effect, and so the beat frequency increases continuously. The theoretical analysis is useful for designing the system for photonic microwave applications.

Transient response of a modulated microwave subcarrier generated using optical injection

“…Physically speaking, the P1 state describes the condition where the slave laser is locked to the injected field and the coupled system oscillates at the injected frequency (f inj ) with sidebands at frequencies of f inj ± f r , where f r is the enhanced resonance frequency of the optically injected laser. As a consequence, the slave laser's electric field oscillates without being damped towards a steady-state value [3][4]. This mode of operation also has the benefit that the longitudinal modes of the Fabry-Perot slave laser are suppressed to a level greater than 30 dB.…”

Chaotic Dynamics of Semiconductor Lasers for Secure Optical Communication

“…Period doubling in the above figure has predicted the dependence on the injection parameters. Recently, the origin of such periodicity was explained as the beating between two wavelengths, namely, the injected wavelength and the cavity resonance wavelength [19].…”

“…While in the latter, the synchronization of the master and slave in a wavelength, phase and chaos state had led the injection locking to broad applications in the coherent communications. Other improvements of the semiconductor laser by optical injection locking had been reported, these improvements include, increasing modulation bandwidth and reducing chirp [3,4], a high gain of 20-dB with small signal modulation below resonance frequency [5]. Bistability had been reported when a two color Fabry-Perot laser was subjected to optical injection in both modes and could be the basis for an all optical memory element with switching times below 500 ps [6].…”

Theoretical and experimental study of polarization switching in long-wavelength VCSELs subject to parallel optical injection

“…Locking of the frequency of the injected laser to the one of the injecting laser has been used for the reduction of the laser linewidth or for an enhancement of its modulation bandwidth [3][4][5]. Nonlinear dynamics of optically injected semiconductor lasers has also been used for photonic microwave generation [6][7][8].…”