These authors contributed equally to this work. Abstract-We experimentally demonstrate an interesting phenomenon of optical bistability in an integrated optical vortex emitter when injecting high power into the waveguide due to the nonlinear optical effects. We clearly observe a hysteresis loop of the radiation power from the integrated vortex beam emitter when increasing and decreasing the input power.
In this paper we have designed a grounded memcapacitor emulator which is a part of memristive system providing a nonlinear relationship between Charge and Voltage. The Floating Current Source (FCS) possesses a low power consumption feature, has been utilized for the memcapacitor emulation. In this study, a memcapacitor emulator is designed utilizing discrete circuit elements. The proposed emulator circuit exhibits a simple design consisting of MOSFETs and capacitors. The emulator performance is verified theoretically, and computer simulations and results are discussed here.
Photonic integrated circuits fabricated on silicon-on-insulator platforms offer convenient foundations to implement highly sensitive, compact, robust, and low-cost technology in sensing applications. The potential of this technology in hydrogen gas sensing is discussed in this study. A single-slot hybrid microring-resonator-(MRR) based hydrogen gas sensor utilizing a coaxial palladium (Pd) microdisk is demonstrated. Detection is based on expansion of Pd upon hydrogen exposure toward the slot between the outer radius of the Pd microdisk and the inner radius of the MRR and the subsequent shift of the whispering gallery modes (WGMs) propagating in the MRR. Finite-difference time-domain simulations indicate a sensitivity as high as 11.038 nm/% hydrogen, provided that optimum geometrical design parameters are chosen. This sensitivity value is ∼23 times higher than other existing WGM-based hydrogen sensor demonstrations.
An integrated approach to thermal modulation of relative phase between two optical vortices with opposite chirality has been demonstrated on a silicon-on-insulator substrate. The device consists of a silicon-integrated optical vortex emitter and a phase controlled 3 dB coupler. The relative phase between two optical vortices can be actively modulated on chip by applying a voltage on the integrated heater. The phase shift is shown to be linearly proportional to applied electrical power, and the rotation angle of the interference pattern is observed to be inversely proportional to topological charge. This scheme can be used in lab-on-chip, communications and sensing applications. It can be intentionally implemented with other modulation elements to achieve more complicated applications.
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