Silicon photonics is one of the most prominent technology platforms for integrated photonics and can support a wide variety of applications. As we move towards a mature industrial core technology, we present the integration of silicon nitride (SiN) material to extend the capabilities of our silicon photonics platform. Depending on the application being targeted, we have developed several integration strategies for the incorporation of SiN. We present these processes, as well as key components for dedicated applications. In particular, we present the use of SiN for athermal multiplexing in optical transceivers for datacom applications, the nonlinear generation of frequency combs in SiN micro-resonators for ultra-high data rate transmission, spectroscopy or metrology applications and the use of SiN to realize optical phased arrays in the 800–1000 nm wavelength range for Light Detection And Ranging (LIDAR) applications. These functionalities are demonstrated using a 200 mm complementary metal-oxide-semiconductor (CMOS)-compatible pilot line, showing the versatility and scalability of the Si-SiN platform.

We report ultra-low propagation losses in silicon sub-micrometric waveguides on a 200 mm CMOS compatible photonics platform. We show median losses in C-band (O-band) as low as 0.1dB/cm and 0.7dB/cm (0.14dB/cm and 1.1dB/cm) in monomode rib and strip waveguides, respectively, thanks to a H2 smoothing annealing. In addition to the significant loss reduction, we show that the performance characteristic of the main passive and active components of the photonics platform are preserved or even improved by the smoothing process.

Generation of optical frequency combs (OFC) using semiconductor laser sources has been an active research topic for years, since they offer good performances for many applications without the bulky and expensive aspects of ion doped fiber or crystal based laser sources. In this paper, we demonstrate the generation of low free spectral range mode-locked laser using hybrid III-V/Si3N4 butt coupling. We start by describing the design and the fabrication process of the active RSOA chip made at our laboratory, and the passive Si3N4 chip having low losses measured to be around 6 dB/m. We then report the integration process and the results of passive mode locking. Our mode-locked laser has a repetition rate of 360 MHz, which is, to the best of our knowledge, the lowest repetition rate achieved for a hybrid integrated mode-locked laser. The frequency comb generated has a 30 dB bandwidth of 2.8 nm (349 GHz). Finally, we show the demonstration of active and harmonic mode locking up to the sixth harmonic.

For the majority of packaging schemes in silicon photonics, out-of-plane optical access to the waveguide layer is achieved via the chip frontside, away from the substrate. As such, fiber grating couplers have generally been optimized with this in mind. In this letter, we present two strategies for designing a fiber grating coupler for coupling to optical fibers placed on the backside of the chip, without the need of superposed reflective layers. An all silicon O-band grating coupler is designed, fabricated and measured with a peak coupling efficiency to a single mode fiber placed on the backside of the chip of -2.8dB and a -1dB bandwidth of ~40nm. In a second approach, a hybrid silicon nitride/silicon O-band grating coupler is measured in the same configuration with a peak coupling efficiency of -3.2dB and a -1dB bandwidth of ~60nm.