Slice-Less Optical Arbitrary Waveform Measurement (OAWM) in a Bandwidth of More than 600 GHz Using Soliton Microcombs

We propose and demonstrate a novel scheme for optical arbitrary waveform measurement (OAWM) that exploits chip-scale Kerr soliton combs as highly scalable multiwavelength local oscillators (LO) for ultra-broadband full-field waveform acquisition. In contrast to earlier concepts, our approach does not require any optical slicing filters and thus lends itself to efficient implementation on state-of-the-art high-index-contrast integration platforms such as silicon photonics. The scheme allows to measure truly arbitrary waveforms with high accuracy, based on a dedicated system model which is calibrated by means of a femtosecond laser with known pulse shape. We demonstrated the viability of the approach in a proof-of-concept experiment by capturing an optical waveform that contains multiple 16 QAM and 64 QAM wavelength-division multiplexed (WDM) data signals with symbol rates of up to 80 GBd, reaching overall line rates of up to 1.92 Tbit/s within an optical acquisition bandwidth of 610 GHz. To the best of our knowledge, this is the highest bandwidth that has so far been demonstrated in an OAWM experiment.

Hardware-efficient megapixel per second coherent soliton microcomb ranging

Laser based ranging (LiDAR) - already ubiquitously used in robotics, industrial monitoring, or geodesy - is a key sensor technology for future autonomous driving, and has been employed in nearly all successful implementations of autonomous vehicles to date. Coherent laser allows long-range detection, operates eye safe, is immune to crosstalk and yields simultaneous velocity and distance information. Yet for actual deployment in vehicles, video frame-rate requirements for object detection, classification and sensor fusion mandate megapixel per second measurement speed. Such pixel rates are not possible to attain with current coherent single laser-detector architectures at high definition range imagining, and make parallelization essential. A megapixel class coherent LiDAR has not been demonstrated, and is still impeded by the arduous requirements of large banks of detectors and digitizers on the receiver side, that need to be integrated on chip. Here we report hardware efficient coherent laser ranging at megapixel per second imaging rates. This is achieved using a novel concept for massively parallel coherent laser ranging that requires only a single laser and a single photoreceiver, yet achieves simultaneous recording of more than 64 channels with distance and velocity measurements each - attaining an unprecedented 5 megapixel per second rate. Heterodyning two offset chirped soliton microcombs on a single coherent receiver yields an interferogram containing both distance and velocity information of all particular channels, thereby alleviating the need to individually separate, detect and digitize distinct channels. The reported LiDAR implementation is hardware-efficient, compatible with photonic integration and demonstrates the significant advantages of acquisition speed, complexity and cost benefits afforded by the convergence of optical telecommunication and metrology technologies.