Photodetectors and modulAtors for free-space optical communications and coherent LIDAR in the Mid InfraRed – PALMIR

The objective of the PALMIR project is to develop and fabricate mid-infrared detectors and modulators operating around 4.8 µm and to implement them in a multifunction transceiver platform to realize a simultaneous telemetry and free-space optical communications demonstration. Several technological building blocks developed at III-V Lab as part of the previous ANR-Astrid HISPANID project (2017-2021, ref. ANR-17-ASTR-0008) allowed the fabrication of a high-speed detector working at 10.3 µm. This initial work permitted to experimentally demonstrate a 10.3 µm QCD infrared (IR) photo-detector in patch antenna configuration, operating at room temperature and with a bandwidth of 25 GHz. These developments permitted to develop know-how and technological building blocks and processes requiring to increase in TRL level of the technology.
In the framework of PALMIR project, we target a wavelength of 4.8 µm, more suited to the identified operational situations. This wavelength shift does not have any major impact on the the technological approach which has been already developed within the framework of HISPANID, neither on the identified QCD detector structures, nor on the production of the patch antennas used for the coupling of the optical signal on the detector. Considering the targeted applications, in PALMIR we will chose to work at few GHz (from 1 to 5 GHz typically).
In the final demonstrator, we will also integrate modulators based on metamaterials developed at LPENS. A collaboration for the development of mid-infrared components has already been set up between TRT and ENS as part of the ENS-Thales Chair and previous collaborative projects (ANR CORALI, joint PhD thesis). TRT will thus have access to 4.8 µm fast modulators and detectors for identified use-cases.
The integration and the electro-optical and thermal packaging of the components will be partially shared and standardized due to the similarities between the modulators and the infrared detectors developed within the framework of the PALMIR project.