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We present an experimental and numerical survey of the switching behavior of cascaded Raman fiber lasers (RFLs). When these lasers are switched on, the output power shows a pulsing behavior where the pulse powers strongly exceed the steady-state output powers. The influence of the pump-laser and fiber properties of a RFL on this dynamical behavior is investigated both experimentally and numerically, where experiments and simulations showed good qualitative agreement. [ABSTRACT FROM AUTHOR]

The longitudinal mode-field components in strongly confining crystalline-silicon waveguides cause a forward–backward asymmetry of the stimulated Raman effect. This nonreciprocity can be used to realise isolators with dynamically reconfigurable isolation direction. [ABSTRACT FROM AUTHOR]

It is shown by numerical simulations that cascaded silicon Raman lasers, in which the pump light undergoes multiple Stokes shifts in a silicon waveguide, can efficiently convert near-IR to mid-IR radiation. For pump wavelengths significantly below 2 µm, two-photon-absorption-induced free-carrier absorption degrades conversion efficiency, and the effective carrier lifetime determines the shortest possible pump wavelength. [ABSTRACT FROM AUTHOR]

A tunable Raman fibre laser (RFL) has been designed such that a wide continuous spectral tuning range spanning several Stokes orders is achieved and the lasing of undesired parasitic resonators is suppressed. A practical design for an RFL, which is continuously tunable over 350 nm spanning the full optical communications wavelength range, is presented. [ABSTRACT FROM AUTHOR]

The Raman-induced nonreciprocity of light propagation in photonic-crystal silicon waveguides is analysed. Although the Raman gain increases in the slow-light regime, the nonreciprocity is smaller. Thus, it is interesting that Raman-pumped optical isolators benefit from slow-light operation. Significant reductions in pump power and/or device length are found to be possible. [ABSTRACT FROM AUTHOR]

Integrated-optical silicon Raman lasers based on a ring cavity can potentially operate unidirectionally owing to the strong non-reciprocity of the Raman gain in submicron photonic wires. This makes the ring-cavity structure significantly more efficient than the alternative Fabry-Perot structure, in which the less efficient of the two propagation directions is unavoidably involved. [ABSTRACT FROM AUTHOR]