The ultimate performance of the Rasnik 3-point alignment system

The Rasnik system is a 3-point optical displacement monitor with sub-nanometer precision. The CCD-Rasnik alignment system was developed in 1993 for the monitoring of the alignment of the muon chambers of the ATLAS Muon Spectrometer at CERN. Since then, the development has continued as new CMOS imaging pixel chips became available. The system's processes and parameters that limit the precision have been studied in detail. We conclude that only the quantum fluctuations to which the light level content of sensor pixels are subject to, is limiting the spatial resolution. The results of two Rasnik systems are compared to results from simulations, which are in good agreement: the best reached precision of \SI{7}{pm/\sqrt{Hz}} is reported. Finally, some applications of high-precision Rasnik systems are set out

Data-driven model to extend tuning range: From 1474 nm to 1568 nm in a monolithic laser

A monolithic laser with a variable outcoupler is tuned from 1474nm to 1568nm. A data-driven model was developed that accurately predicts the laser tuning range. This model shows that a 4-Arm filter and a variable outcoupler can increase the tuning range over 120nm

Hybrid modeling technique for on-chip extended cavity semiconductor mode-locked lasers

This work presents a hybrid modeling technique to simulate extended cavity semiconductor mode-locked lasers, using a combination of traveling wave equations with the nonlinear Schrödinger equation. The simulations are compared to and show correspondence with experimental results from a III-V-on-silicon mode-locked laser

Filling the gap of silicon nitride photonic platform functionalities using micro-transfer printing

International audienceIn this work we demonstrate the heterogeneous integration of active devices on the SiN photonic platform using micro-transfer printing and we will discuss the remaining technological challenge

Tensio+: a fabric tension meter for the paper industry

Paper is produced in vast quantities in paper mills. The properties of the produced paper critically depend on the parameters of the mill, especially the properties of the fabric belt transporting the fibre-water mixture that is converted into paper through the mill. The belt properties are currently monitored by indirect methods and imprecise measurement devices. The company Feltest Equipment BV aims to improve this situation by developing measurement equipment to monitor the belt properties in a direct fashion

Saturable absorption of a double layer graphene modulator on a slot waveguide

The saturable absorption of a double-layer graphene modulator is experimentally demonstrated on a silicon slot waveguide platform. Saturation was found to start at ~0.8W with a maximum saturation depth of 1.9 dB for a 50μ

The ultimate performance of the Rasnik 3-point alignment system

The Rasnik system is a 3-point optical displacement monitor with sub-nanometer precision. The CCD-Rasnik alignment system was developed in 1993 for monitoring the alignment of the muon chambers of the ATLAS Muon Spectrometer at CERN. Since then, the development has continued as new CMOS imaging pixel chips became available. In this work the system processes and parameters that limit the precision are studied. We conclude that the spatial resolution of Rasnik is only limited by the quantum fluctuations of the photon flux arriving at the pixels of the image sensor. The results of two Rasnik systems are compared to results from simulations, which are in good agreement. The best spatial resolution obtained was 7 pm/Hz. Finally, some applications of high-precision Rasnik systems are set out.ImPhys/Hoogenboom grou