Experimental platform for Optical OFDM systems
Within the ADRENALINE testbed®, we have implemented an experimental platform for the development and assessment of optical connectivity solutions based on multicarrier technology (either OFDM, or discrete multitone, DMT) transmission and alternative reception schemes adopting offline processing. Different programmable digital signal processing (DSP) modules are available for adaptive loading, digital mixing, channel signal to noise ratio (SNR) estimation, equalization, self-performance monitoring and impairment compensation. Additionally, the EOS platform can be configured with a suitable choice of alternative options of optical, electro-optical and electrical devices, available in the lab, required to implement flexible optical transmission systems, based on modular transceiver architecture, as shown in the figure. This platform is connected to the 4-node photonic mesh network in order to encompass different setups, including optical and optoelectronic systems and subsystems, mainly for multicarrier modulation (MCM) transmission and reception based on offline DSP. According to the figure, different (S)-BVT modules, composing the S-BVT and based on MCM (DMT/OFDM), can be developed within the EOS platform.
There are also specialized laboratory facilities with the common tools for development and experimental assessment of optical connectivity solutions. The facilities include optical communication test and measurement equipment, optical network test and measurement equipment, hardware design and development, simulation engines, and software design and development.
Regarding the experimental platform for Optical OFDM systems, possible extensions are related to
i) Implementation of multicarrier/multidimensional (WDM/SDM) optical transmission systems fully exploiting the spectral and spatial dimensions to obtain ultra-high capacity troughput and enable advanced functionalities and full programmability (integration with control plane)
ii) Validation and testing of optical transceivers based on photonic technologies and devices. The upgrade towards including novel, advanced photonic technologies/devices will be performed by adquiring an articulated base for coarse alignment and specific tools for photonic chip characterization. Indeed, by the adoption of photonic technologies reduced cost, power consumption and footprint of the optical subsystems is expected to be achieved.
iii) Development of monitoring systems and subsystems for network telemetry, including suitable optoelectronic front-ends and (AI-assisted) DSP. In fact, low-cost front-end solutions agnostic to the modulation format and optical waveforms are targeted, in order to allow a massive deployment in any transport optical network. These front-ends serve raw data to the DSP, eventually including AI parts, in order to extract the suitable features and figures of merit of the channels/links monitored.
On the one hand, at the transmitter side, either an arbitrary waveform generator (up to 24 GSa/s) or a high-speed digital to analogue converter (DAC up to 64 GSa/s), included in the platform, can be used to create electrical analogue signals. Different optoelectronic transmitter front-end modules based on direct or external modulation can be adopted and suitably integrated within the EOS platform. The flows aggregation/distribution is performed by using a bandwidth variable (BV) WSSs, based on liquid crystal on silicon technology (LCoS), which can be part of either the transceiver or the network. On the other hand, several optical reception options, based on direct or coherent detection, are available within the EOS platform.