Integrated Remote Laser Source for 6G Advanced Antenna Systems

Future generations of mobile communications promise near unlimited access to information and data sharing with ubiquitous wireless connectivity for any kind of device and application that may benefit from being connected. This poses new design challenges and requires a renewal of the hardware platforms to meet the increased demand of capacity and reliability of the network. Next generation Radio Access Network (RAN) will evolve towards an increase of the radio bandwidth, with carrier frequency extended to the millimeter waves (mmW) range. Other technologies that will be extensively used to increase the RAN capacity will be beamforming and spatial multiplexing with advanced antenna systems (AAS) comprising hundreds of antenna elements. Optical technologies are the natural candidates to support the traffic increase, by providing high-capacity interconnection within the radio unit and towards the base band unit (BBU). However, the higher level of integration of AAS will cause an increase of the temperature to values >100°C, due to power dissipation of RF power amplifiers (PA), digital front-end (DFE) and baseband processing Application Specific Circuits (ASIC). This makes the AAS an inhospitable environment for optical transceivers that include lasers, typically operating at temperatures <85°C. A promising approach to solve this issue is to place the laser outside the transceiver as a remote laser source (RLS) in a less harsh environment or in a thermally controlled environment e.g., in the same cabinet of the BBU. In this article we demonstrate a fully integrated RLS enabling a reduction of power consumption and packaging cost.