We propose a scheme of a bistable system with an electromagnetically induced grating and analyse the optical bistabilities in the system. The stationary equations describing the system have been derived. This bistable system shows typical hysteresis behaviour.
A new use of gratings in nonlinear optics is presented, i.e., the realization of bistable components. The device studied here consist of grating couplers ruled on a Kerr nonlinear medium, which use the guided-wave resonance to increase the local field and thus the nonlinearities. The result is that they are intrinsic bistable optical systems with high-speed, low pumping thresholds, and geometry well adapted to optical integration. First, a linear electromagnetic study of the devices is presented. It follows optimizing the grating parameters in order to get the best coupling between the incident beam and the guided mode inside the corrugated waveguide. Then a graphical construction is given that demonstrates the bistable character of the system in nonlinear optics. Next a nonlinear analysis of the devices is rigorously derived from Maxwell equations. It states precisely the predictions of the graphical construction and allows comparison of the effectiveness of the guided-wave resonance with the surface plasmon resonance in order to reduce the threshold of bistability.
The nonlinear phenomena of optical bistablity is investigated analytically in chalcogenide glass long period fiber grating. Using the basic sets of nonlinear coupled mode equation the expression for the transmittivity of grating has been derived under nonlinear Kerr regime. To examine the bistable charateristics of the grating, the operating wavelength is considerd slightly above the resonance wavelength of 1550 nm i.e. for off resonance condition where detuning parameter δ≠0. It is observed that the intensity of the transmitted wave increases with increasing input intensity and reaches its maximum value at particular intensity. On gradual reduction of the input intensity, the transmitted intensity does not retrace the same path, resulting in a hysteresis loop. This hysteresis loop shows that the LPFG supports the occurrence of optical bistability.