Martin Peyrou

We report on the performance of a silicon photonic integrated circuit for laser frequency chirping, developed for FMCW LIDAR applications. An external laser source is fiber coupled to the photonic circuit and frequency chirping is achieved with a silicon IQ modulator and a monolithically integrated III-V/Si semiconductor optical amplifier to compensate for IQ modulator losses. A chirp distortion of 1.8% over 5% to 95% of the chirp ramp period was measured with a delayed self-heterodyne interferometric method. The high chirp linearity of our circuit is confirmed by FMCW ranging measurements using 2-18 m long fiber delay lines. The resulting beat frequency follows a linear dependency with the fiber delay line length (R²=0.999).

We demonstrate a 4λx8 output DFB laser comb source with 94GHz channel spacing. The comb source produces approximately 1mW of fiber-coupled power per wavelength per fiber with 2dB power variability across all 32 output channels.

The evolution beyond 5G towards 6G will accelerate the transformations begun by 5G to deploy new approaches to define delivery services. The network should be accessible anywhere, always-on and with the guarantee performances. This poses new challenges to the transport network that should assure available connectivity among the functions at different levels of granularity. The transport network should be so flexible to guarantee on-demand the connectivity among the processing functions that automatically will be required and, at the same time, should assure extreme performance. Optical network and Dense Wavelength Division Multiplexing technology are relevant candidates to match high bandwidth and low latency, but new challenges are required to assure the suitable cost and size for the wireless access networks. The current optical technology, suitable used in aggregation and long-haul transport network, cannot be simply downsized to be used in the access area, but novel paradigm should be considered for the optics as well. Integrated photonics seems a promising direction to realize low cost and low size optical components for the transport network. Moreover, this technology enables a certain level of remote tunability and reconfiguration of optical equipment that allow to simplify and reduce cost of installation in field and operation of the transport network. In this paper relevant optical components for transport networks are analyzed using the integrated photonics to assess the technology challenges.