Silicon photonic sensors are promising candidates for lab-on-a-chip solutions with versatile applications and scalable production prospects using complementary metal-oxide semiconductor (CMOS) fabrication methods. However, the widespread use has been hindered because the sensing area adjoins optical and electrical components making packaging and sensor handling challenging. In this work, a local backside release of the photonic sensor is employed, enabling a separation of the sensing area from the rest of the chip. This approach allows preserving the compatibility of photonic integrated circuits in the front-end of line and metal interconnects in the back-end of line. The sensor is based on a micro-ring resonator and is fabricated on wafer-level using a CMOS technology. We revealed a ring resonator sensitivity for homogeneous sensing of 106 nm/RIU.

In recent decades, much research effort has been invested in the development of photonic integrated circuits, and silicon-on-insulator technology has been established as a reliable platform for highly scalable silicon-based electro-optical modulators. However, the performance of such devices is restricted by the inherent material properties of silicon. An approach to overcoming these deficiencies is to integrate organic materials with exceptionally high optical nonlinearities into a silicon-on-insulator photonic platform. Silicon-organic hybrid photonics has been shown to overcome the drawbacks of silicon-based modulators in terms of operating speed, bandwidth, and energy consumption. This work reviews recent advances in silicon-organic hybrid photonics and covers the latest improvements to single components and device concepts. Special emphasis is given to the in-device performance of novel electro-optical polymers and the use of different electro-optical effects, such as the linear and quadratic electro-optical effect, as well as the electric-field-induced linear electro-optical effect. Finally, the inherent challenges of implementing non-linear optical polymers on a silicon photonic platform are discussed and a perspective for future directions is given.

Nonlinear optical dyes doped in optical polymer matrices are widely used for electro-optical devices. Linear optical properties change with dye concentration, which leads to a change in modal properties, especially in nano-structured integrated waveguides such as silicon slot-waveguides. Here, we investigate the influence of a nonlinear optical dye on the performance of a silicon-organic hybrid slot-waveguide. A simulation study of the modal and optical confinement properties is carried out and dependence of the structural parameters of the slot-waveguide and the organic cladding material is taken into account. As cladding material, a guest-host polymer system is employed comprising the nonlinear optical dye Disperse Red 1 (DR1) doped in a poly[methyl methacrylate] (PMMA) matrix. The refractive indices of doped and undoped PMMA were deduced from ellipsometric data. We present a guideline for an optimized slot-waveguide design for the fabrication in silicon-on-insulator technology giving rise to scalable, high-performance integrated electro-optical modulators.

No abstract

1225Studying thin magnetic metal films on semicon ductor substrates is now of particular interest due to new physical properties of these structures and the prospects of their application in spintronics [1][2][3]. The film thicknesses in those works were varied from several fractions of a nanometer to tens of nanometers. The technological growth parameters are usually cho sen using preliminary calibrations, which can substan tially change during growth. Therefore, it is necessary to control the layer thickness in such a structure during growth.The experimental techniques most widely used to perform in situ film thickness control during growth are as follows: thickness measurement from the differ ence between beats in a quartz resonator, the high energy electron diffraction, and ellipsometry. To obtain reliable film thicknesses using a quartz resona tor, it should be located as close as possible to a synthe sis region and should be thermally stabilized, which requires an additional complication of the experimen tal technique. Moreover, this method is inconvenient during the formation of multicomponent systems. The diffraction of fast electrons can be used to calculate the coating thickness from specular reflection oscillations during layer by layer growth of epitaxial films [4] and cannot be used for thickness measurements during the formation of polycrystalline and amorphous struc tures.Among these methods, ellipsometry is a sensitive method that can almost continuously obtain informa tion on the processes occurring on the surface of a growing sample without affecting its structure. Apart from thickness, an ellipsometric experiment can also give information on the optical properties, in particu lar, the depth profiles of optical constants in a nonuni form layer [5][6][7][8][9]. Modern fast ellipsometers can main tain an almost continuous ellipsometric data flow measured during growth, which opens up fresh oppor tunities for solving the inverse problem of ellipsometry in a nondestructive manner. This problem can rather easily be solved when the thickness dependence of the ellipsometric parameters is known [8]. In a real exper iment, however, the ellipsometric parameters are mea sured during growth as functions of time and can only roughly be estimated if the growth rate is calibrated.Shvets [9] considered the problem of restoring optical constant profiles from a "growth curve," namely, the ellipsometric parameters measured during the growth of a nonuniform layer. He proposed an algorithm to determine these profiles, which achieved good results provided the gradient of the optical con stants is small, G = λ|dN/dz| Ӷ 1, where N = n -ik is the complex refractive index and λ is the wavelength. This algorithm is based on the relative derivatives of the ellipsometric parameters determined experimen tally from the growth curve at a high density of mea sured points. For the reverse inequality (G ӷ 1), gen Abstract-An algorithm is developed to perform rapid control of the thickness and optical constants of a film structure...