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Register a new userPhase locking of coupled lasers with many longitudinal modes
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Detailed experimental and theoretical investigations on two coupled fiber lasers, each with many longitudinal modes, reveal that the behavior of the longitudinal modes depends on both the coupling strength as well as the detuning between them. For low to moderate coupling strength only longitudinal modes which are common for both lasers phase-lock while those that are not common gradually disappear. For larger coupling strengths, the longitudinal modes that are not common reappear and phase-lock. When the coupling strength approaches unity the coupled lasers behave as a single long cavity with correspondingly denser longitudinal modes. Finally, we show that the gradual increase in phase-locking as a function of the coupling strength results from competition between phase-locked and non phase-locked longitudinal modes.
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A unique approach for steady in-phase locking of lasers in an array, regardless of the array geometry, position, orientation, period or size, is presented. The approach relies on the insertion of an intra-cavity Gaussian aperture in the far-field plane of the laser array. Steady in-phase locking of $90$ lasers, whose far-field patterns are comprised of sharp spots with extremely high power density, was obtained for various array geometries, even in the presence of near-degenerate solutions, geometric frustration or superimposed independent longitudinal modes. The internal phase structures of the lasers can also be suppressed so as to obtain pure Gaussian mode laser outputs with uniform phase and overall high beam quality. The approach could potentially improve the performances of recently developed laser simulators that are used for solving various computational problems.
We report on the phase-locking of two diode lasers based on self-seeded tapered amplifiers. In these lasers, a reduction of linewidth is achieved using narrow-band high-transmission interference filters for frequency selection. The lasers combine a compact design with a Lorentzian linewidth below 200 kHz at an output power of 300 mW. We characterize the phase noise of the phase-locked laser system and study its potential for coherent beam-splitting in atom interferometers.
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We present a systematic analysis of the stationary regimes of nonlinear parity-time(PT) symmetric laser composed of two coupled fiber cavities. We find that power-dependent nonlinear phase shifters broaden regions of existence of both PT-symmetric and PT-broken modes, and can facilitate transitions between modes of different types. We show the existence of non-stationary regimes and demonstrate an ambiguity of the transition process for some of the unstable states. We also identify the presence of higher-order stationary modes, which return to the initial state periodically after a certain number of round-trips.
Motivated by recent experiments, which demonstrated lasing and cooling of the electromagnetic field in an electrical resonator coupled to a superconducting qubit, we study the phase coherence and diffusion of the system in the lasing state. We also discuss phase locking and synchronization induced by an additional {sl ac} driving of the resonator. We extend earlier work to account for the strong qubit-resonator coupling and to include the effects of low-frequency qubits noise. We show that the strong coupling may lead to a double peak structure of the spectrum, while the shape and width are determined to the low-frequency noise.
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