The VTRx+, an optical link module for data transmission at HL-LHC

Optical data transmission will remain a key enabling technology for the upgrading detectors at HL-LHC. In particular the inner tracking detectors will require low-mass, radiation tolerant optical transmit and receive modules for tight integration in the detector front-ends. We describe the development of such a module, giving details of the design, functional and environmental performance, as well as showing the feasibility of achieving small size, low-mass, and low-power operation

Effects of High Fluence Particle Irradiation on Germanium-on-Silicon Photodiodes

Waveguide-Integrated germanium-on-silicon (Ge-on-Si) photodiodes (PDs) are integral components in silicon photonics (SiPh) and understanding their radiation tolerance is important for applications that intend to use SiPh in harsh radiation environments. Here we report the results of high fluence particle irradiation tests on Ge-on-Si PDs. The PD samples are irradiated using neutrons and protons, with fluences reaching up to $\mathrm {3 \times 10^{16}~n / \text {cm} ^{2} }$ (23 MeV) and $\mathrm {4.1 \times 10^{16}~p / \text {cm} ^{2} }$ (24 GeV), respectively. Throughout the neutron irradiation, changes in PD responsivity and dark current are monitored, while the capacitance and current-voltage-characteristics are measured during the proton irradiation test. The results reveal only minimal losses in responsivity, along with moderate increases in dark current and capacitance. These observed changes could impose limitations on applications that demand high bandwidth in extreme radiation environment. However, it is worth noting that for example high-energy physics experiments, which represent some of the most extreme radiation environments, do not necessarily require exceptionally high receiver bandwidths. Consequently, our findings demonstrate excellent radiation tolerance that fulfills the requirements of next-generation high-energy physics experiments.Waveguide-Integrated Germanium-on-Silicon (Ge-on-Si) photodiodes are integral components in silicon photonics and understanding their radiation tolerance is important for applications that intend to use silicon photonics in harsh radiation environments. Here we report the results of high fluence particle irradiation tests on Ge-on-Si photodiodes. The photodiode samples are irradiated using neutrons and protons, with fluences reaching up to 3 × 10 16 n/cm 2 (23 MeV) and 4.1 × 10 16 p/cm 2 (24 GeV), respectively. Throughout the neutron irradiation, changes in photodiode responsivity and dark current are monitored, while the capacitance and current-voltage characteristics are measured during the proton irradiation test. The results reveal only minimal losses in responsivity, along with moderate increases in dark current and capacitance. These observed changes could impose limitations on applications that demand high bandwidth in extreme radiation environment. However, it is worth noting that for example high-energy physics experiments, which represent some of the most extreme radiation environments, do not necessarily require exceptionally high receiver bandwidths. Consequently, our findings demonstrate excellent radiation tolerance that fulfills the requirements of next-generation high-energy physics experiments

System Development of Radiation-Tolerant Silicon Photonics Transceivers for High Energy Physics Applications

Silicon photonics enables the manufacturing of high-speed, low-power, integrated optical circuits with compact footprints, and recent studies have also shown it to have a high tolerance to radiation. The technology has, therefore, been identified as an excellent candidate for the development of the next generation of radiation-tolerant optical links for high-energy physics (HEP) experiments at CERN. This article presents the results of the characterization and modeling of building block devices and circuits for custom radiation-tolerant transceivers based on silicon photonics. We demonstrate a four-channel wavelength division multiplexing (WDM) transmitter (Tx) based on microring modulators (RMs) operating at 25 Gb/s per lane, and a polarization-insensitive receiver (Rx) based on germanium photodiodes (PD). Solutions for the thermal tuning of the RMs and on- chip active polarization control are also reported

Background and muon counting rates in underground muon measurements with a plastic scintillator counter based on a wavelength shifting fibre and a multi-pixel avalanche photodiode readout

In this short note we present results of background measurements carried out with polystyrene based cast plastic 12.0×12.0×3.0 cm3 size scintillator counter with a wavelength shifting fibre and a multi-pixel Geiger mode avalanche photodiode readout in the Baksan underground laboratory at a depth of 200 metres of water equivalent. The total counting rate of the scintillator counter measured at this depth and at a threshold corresponding to ∼0.37 of a minimum ionizing particle is approximately 1.3 Hz.peerReviewe