https://www.selleckchem.com/products/elexacaftor.html We present a multi-point curvature sensor based on optical fiber specklegram measurements. Apart from the current approaches, the proposed system uses an ordinary multimode fiber excited with visible light as a reflection-type probe. Besides, this method discretizes the waveguide into segments connected by joints and assumes sequential bend events, simplifying the specklegram referencing for correlation analyses and avoiding laborious deep learning processing. Sensor characterization yielded a linear response with ∼1.3∘ resolution for single curvatures, whereas shape prediction experiments in the plane resulted in maximum errors of ∼3.5∘ and ∼5.4mm for angular and linear positioning, respectively. Furthermore, exploratory tests indicated errors less then 2.3∘ regarding probe curvatures in the space. This research introduces a feasible, straightforward alternative to the available shape sensors, enabling applications in medical probes and soft robotics.In this work, an analytical method is proposed to determine the effective focal length and the six cardinal points for a system of coaxial thick lenses. The technique is different from both the Gaussian and matrix methods. We can apply it without the need to calculate the power and the principal points of the individual lenses of the system. The method is based on a proposed formula for the focal length of a whole system of coaxial thick lenses. This formula is derived in detail in the present work. The proposed method represents a simpler alternative to the Gaussian reduction method. Several numerical examples are solved in this work using the method. In these examples, we have easily calculated the effective focal length and the six cardinal points for coaxial systems of two, three, and five thick lenses in the most general case of different refractive indices.Opto-electro modulators with nanometer-scale footprint are indispensable in integrated photonic electroni