In this article the process of realization of ball-lensed optical fibers is described. The implementation of four different types of ball-lensed optical fibers developed in Optical Fibers Techniques Laboratory at Lodz University of Technology is presented. Focal lengths of the presented microlenses, which were obtained in simulations and measurements, are also shown in this paper.

One of the major performance limitations in chip designs is clock skew, the uncertainty in arrival times between a pair of clocks. Clock skew can limit overall circuit performance, or even cause functional errors. The main goal of this paper is to analyse and compare the most popular analytical models for estimating the clock skew for present and future VLSI systems. These models are compared for a generic global clock distribution network (an H-tree) with a JAVA program. Finally based on the presented models, a prevision for the clock skew value in upcoming technology nodes will be given.

This paper examined the impact of optical fiber sensor design, and its integration to PVC (polyvinyl chloride) sheet piles, on deflection and strain monitoring. Optical fiber sensors based on Brillouin light backscattering (BLS) were prepared, as they can provide accurate strain and deflection measurement results. However, depending on the application of sheet piles systems, high deformation of PVC elements can be observed. Therefore, a fiber sensor design is not trivial. Three types of optical fiber coatings and their integration with PVC sheet piles were investigated. The effect on the value of compressive and tensile strain were analyzed. It has been experimentally proven that PVC sheet piles monitoring, based on BLS method, can be realized using optical fibers with 250 µm, 900 µm, and 3 mm coating diameter. Achieved results are in line with theory. Correction coefficient necessary for 900 µm and 3 mm coatings has been proposed and used to ensure proper strain measurement. It was found that 250 µm coating fiber based sensors can be utilized for PVC strain measurement under low deflection (>1.2 m beam length). On the other hand, sensors based on 3 mm coating fiber, due to a high level of linearity, can be applied to deflection distance measurement under high deformation.

The optical clock distribution has been considered to alleviate limitations due to metallic interconnections for future generation of VLSI. It can be interesting only, if it is able to provide some substantial improvement of IC features. This paper studies the effects of the VLSI structure thermal gradients on the clock skew in optical clock distribution network CDN.

The main goal of this paper is to show that using Bragg grating filter with apodized duty cycle it is possible to realize a 10 GHz channel spacing DWDM system. The way to find the best configuration of the grating taking into consideration the lowest level of the first side lobe in the reflection spectrum is shown. Then the solution to eliminate crosstalk for the 10 GHz channel shift is explained and the method for dynamic selection of the channel is proposed.

This paper is focused on the latency and power dissipation in clock systems, which should be lower when the optical interconnects are applied. Simulation shows that the power consumed by an optical system is lower than that consumed by an electrical one, however the advantages of optics drastically decrease with the number of output nodes in H-tree. Additionally, simple replacement of an electrical system by an optical clock distribution network (CDN) results in high clock skew, which will be higher than 10% of the clock period for the 32 nm technology node.