Stephane Detraz

Radiation Damage Studies of Lasers and Photodiodes for Use in Multi-Gb/s Optical Data Links

Neutron and pion irradiation and annealing data from semiconductor lasers and photodiodes for use in 10 Gb/s datalinks are presented. These components are found to be generally more radiation resistant than their older counterparts. Radiation damage in lasers has been modeled to allow extrapolation of the results obtained to the final application.

The Versatile Transceiver: towards production readiness

Detectors involved in the upgrade programme of the LHC will need high-speed optical links to transfer readout and control data. The link front-end will be based on a radiation tolerant opto-electronic module, the Versatile Transceiver (VTRx), developed under the Versatile Link project. In this contribution we present a test system and protocol to be used to verify the compliance of the VTRx modules to the specifications, and a Versatile Link demonstrator based on the VTRx and the Gigabit Link Interface Board. Finally, we introduce the Small Footprint VTRx which is being designed for the CMS Tracker upgrade.

Versatile Transceiver developments

SLHC experiment upgrades will make substantial use of optical links to enable high-speed data readout and control. The Versatile Link project will develop and assess optical link architectures and components suitable for deployment at SLHC. The on-detector element will be a bidirectional opto-electronic module: the Versatile Transceiver (VTRx) that will be based on a commercially available module type minimally customized to meet the constraints of the SLHC on-detector environment in terms of mass, volume, power consumption, operational temperature and radiation environment. This paper brings together the status of development of the VTRx in terms of packaging, environmental testing and functional testing.

Single-Event Upsets in Photoreceivers for Multi-Gb/s SLHC Data Transmission

A 63 MeV proton beam was used to perform a single event upset (SEU) test on a candidate component for a future high luminosity large hadron collider (HL-LHC) high speed optical. An in-lab error injector was used to show that 1-0 bit errors are caused by the amplifiers response to the large signal caused by a single event transient (SET) in the photodiode.

Single-Event Upset testing of the Versatile Transceiver

The Versatile Transceiver (VTRx) will be deployed on detectors that will be operated at the upgraded HL-LHC where the instantaneous luminosity will be increased by a factor of 5–10 with respect to the nominal LHC. All components housed at the front-ends must thus be immune to single-event-upsets (SEUs) to a level compatible with the correct operation of the detector systems. We report the results of SEU testing of the full VTRx in a proton beam-line.

Modeling TID Effects in Mach-Zehnder Interferometer Silicon Modulator for HL-LHC Data Transmission Applications

High-speed Mach-Zehnder interferometer silicon modulators were exposed to a total ionizing dose of 1.3 MGy, levels comparable to the worst radiation levels for a tracking detector after 10 years of operation at the High-Luminosity LHC, show a sensitivity to ionizing radiation after exposure to a dose of a few hundred kGy. A physical model to describe the effect of ionizing radiation on the modulators has been developed and is used to predict whether a more radiation-hard modulator can be designed to survive the harshest radiation environments expected at the HL-LHC.

Versatile transceiver development status

The Versatile Link common project is developing optical link architectures and components to be used for readout and control of future HL-LHC experiments. The on-detector opto-electronic module, the Versatile Transceiver (VTRx), is derived from an industry standard module type and is adapted through minimal customization to the requirements dictated by the HL-LHC-specific front-end environment. We present the methods and results of the functional tests carried out on the transceiver components and summarize the development status of the different VTRx variants. Finally we show the results obtained using the packaged VTRx module.

Laser and photodiode environmental evaluation for the Versatile Link project

We summarize the results obtained in a series of radiation tests of candidate laser and photodiode components for use in the Versatile Transceiver (VTRx), the front-end component of the Versatile Link. We have carried out radiation testing at a full spectrum of sources (neutrons, pions, gammas) and can now compare the results and show that the range of components that meet the radiation tolerance requirements is rather large. In addition, devices have been operated in a high magnetic field to qualify them for use in (HL-) LHC detectors.

High Dose Gamma Irradiation of Lasers and p-i-n Photodiodes for HL-LHC Data Transmission Applications

Lasers and photodiodes for high luminosity large Hadron collider (HL-LHC) data transmission applications were irradiated with a 1-Gy dose of 60Co gammas. No change was observed in the performance of the lasers tested, and an order of magnitude increase in the leakage current of the InGaAs photodiodes was measured.

FPGA-based bit-error-rate tester for SEU-hardened optical links

The next generation of optical links for future High-Energy Physics experiments will require components qualified for use in radiation-hard environments. To cope with radiation induced single-event upsets, the physical layer protocol will include Forward Error Correction (FEC). Bit-Error-Rate (BER) testing is a widely used method to characterize digital transmission systems. In order to measure the BER with and without the proposed FEC, simultaneously on several devices, a multi-channel BER tester has been developed. This paper describes the architecture of the tester, its implementation in a Xilinx Virtex-5 FPGA device and discusses the experimental results.