We propose an all-optical channel switch based on lattice solitons with weak light to control an intense light. Through adjusting the power, position and incident angle of the controlling light, the signal light can be switched to different channels. In the switching process, the signal light loses little energy.
We propose a scheme of interaction-free bidirectional multi-channel all-optical switching in a multi-level coupling system consisting of four-level atoms confined in a cavity and coupled by a free-space control laser. A signal laser field is coupled into the cavity and excites two separate transitions of atoms simultaneously under the collective strong coupling condition. The transmission and reflection of signal fields form bidirectional output channels. A free-space control laser induces destructive quantum interference in the multi-level excitation of an atom-cavity system, which can be used to switch on/off the output signal lights of transmission/reflection channels. There is no direct coupling of control light and signal light through the cavity-confined atoms because the output of signal light is nearly totally suppressed to the opposite direction when control light is present. The proposed all-optical switching scheme can be realized with high switching efficiency, broad bandwidth, and weak light intensity. It may be useful for future devices of optical routing, optical communications, and various quantum logic elements.
The optical solitons (temporal and spatial) are very promising for all-optical switching and logic gates due to stability and uniform phase along the pulse. Various schemes have been demonstrated (see, for instance, [1-4]), however in all those schemes the power of the control wave was more or comparable with the power of the signal wave. We propose a scheme where the control wave power is approximately 2-4% of the signal wave power. This scheme is based on the control of the bright spatial soliton interaction.
A novel concept for an all-optical transistor is proposed and verified numerically. This concept relies on cross-phase modulation between a signal and a control pulse. Other than previous approaches, the interaction length is extended by temporally locking control and the signal pulse in an optical event horizon, enabling continuous modification of the central wavelength, energy, and duration of a signal pulse by an up to sevenfold weaker control pulse. Moreover, if the signal pulse is a soliton it may maintain its solitonic properties during the switching process. The proposed all-optical switching concept fulfills all criteria for a useful optical transistor in [Nat. Photon. 4, 3 (2010)], in particular, fan-out and cascadability, which have previously proven as the most difficult to meet.
A scheme is proposed for tunable all-optical switching based on the double-dark states in a five-level atom-cavity system. In the scheme, the output signal light of the reflection and the transmission channels can be switched on or off by manipulating the control field. When the control light is coupled to the atom-cavity system, the input signal light is reflected by the cavity. Thus, there is no direct coupling between the control light and the signal light. Furthermore, the position of the double-dark states can be changed by adjusting the coherent field, and, thus, the switching in our scheme is tunable. By presenting the numerical calculations of the switching efficiency, we show that this type of the interaction-free all-optical switching can be realized with high switching efficiency.
We investigate propagation and control of weak-light spatial solitons in a resonant three-level atomic system with a periodic modulated control field. It is shown that the periodic modulation acts like periodic potential which resists the propagation of the soliton in transverse direction. The soliton could be trapped by the periodic potential in the input channel. When the modulation is canceled, the soliton propagates in its initial incident direction. The periodic modulation of control field could be used to control the propagation of the weak-light probe soliton. Due to the good localization efficiency of the periodic potential, an excellent switching is realized for the probe soliton. These properties may have potential applications in all-optical switching, optical information processing and other fields.
We study the interaction between an intense soliton and a weak control pulse in optical media with a zero-nonlinearity wavelength (ZNW). By means of numerical simulations, we show that the soliton’s wavelength and group delay can be modified by a proper choice of parameters of the control pulse, such as its power, frequency, and initial delay. Most remarkably, we demonstrate either the suppression of the soliton’s Raman-Induced Frequency Shift (RIFS) or the enhancement of this effect and explain it by temporal analogies of reflection and transmission. Finally, we propose an all-optical switching scheme based on time and frequency windows.