O-Band Grating Couplers Using Silicon Nitride Structures

Abstract

To test silicon photonics component performances, a silicon (Si) grating coupler (GC) is used to couple the light from a single-mode fiber (SMF) into the chip. However, silicon nitride (Si3N4) waveguides have recently become more popular for realizing photonic integrated circuits (PICs), which may be attributable to their exceptional characteristics, such as minimal absorption and low back reflection (BR) in the O-band spectrum. Thus, to test the photonic chip, a waveguide converter from Si3N4 to Si needs to be added to the photonic circuit, which can lead to more power losses and BR. To avoid this conversion, we propose in this manuscript a configuration of a GC based on Si3N4 structures, which can be employed to minimize the footprint size and obtain better performance. The achievement of high efficiency was possibly obtained by optimizing the structural properties of the waveguide and the coupling angle from the SMF. The results demonstrated high efficiency within the O-band spectrum by using a wavelength of 1310 nm. Notably, at this specific wavelength, the findings indicated a coupling efficiency of −5.52 db. The proposed design of the GC consists of a uniform grating that offers improvements regarding affordability and simplicity in manufacturing compared to other GC models. For instance, using a reflector or a GC with non-uniform grooved teeth introduces challenges in fabrication and incurs higher costs. Thus, the proposed design can be useful for improving the testing abilities of the Si3N4 photonic chips used in transceiver systems.

Photonic Integrated Circuits for Microwave Astronomy

“…The time-ordered data (TOD) are then obtained from the 4 different 90 • hybrid outputs for different values of the input polarization signal. Finally, the TODS are further analyzed with the final aim of recovering their amplitudes and phases and thus (after taking into account the specific phase corrections per channel; Equation (11) in [9]) recovering the input polarization angle and degree and their accuracy.…”

“…Some of the components that have been used for the designed chip are similar to those that can be found in [10] for SiN technology. Other examples of this alternative technology's application can be found in [11,12].…”

Data Center Four-Channel Multimode Interference Multiplexer Using Silicon Nitride Technology

“…Si 3 N 4 is selected for the waveguide core due to its favorable characteristics in the O-band spectrum, including low propagation loss and high refractive index contrast with silicon dioxide (SiO 2 ) cladding [ 21 ]. Si 3 N 4 has a low material absorption coefficient in the near-infrared to the mid-infrared regions, which translates to low propagation losses [ 22 ].…”