Optical coupling between preferential-order volume diffraction grating couplers fabricated on independent substrates is demonstrated. The coupling efficiency between gratings is quantified as a function of both grating and waveguide fabrication technology and relative angular position of the two substrates. A maximum grating-to-grating coupling efficiency of 31% is reported for coupling between...

On-chip optical data processing and photonic quantum integrated circuits require the integration of densely packed directional couplers at the nanoscale. However, the inherent evanescent coupling at this length scale severely limits the compactness of such on-chip photonic circuits. Here, inspired by the adiabatic elimination in a N-level atomic system, we report an experimental realization of ...

A boundary variation method for the fast and accurate modeling of three-dimensional waveguide grating couplers is presented. The algorithm is verified by detailed comparisons with the results of a rigorous spectral collocation method, showing excellent agreement. Examples of the modeling of large waveguide grating couplers are given to illustrate the applicability and versatility of the method.

Directional couplers are critical components in photonic integrated circuits used in optical communication systems. The conventional directional couplers with laterally arranged waveguides can not achieve very short coupling lengths due to extreme sensitivity to fabrication variations and limitations to produce uniformly very narrow gap layers.1) Vertical directional couplers, however, can obta...

In this paper, the feasibility of Substrate Integrated Waveguide (SIW) couplers, fabricated using single-layer TACONIC RF-35 dielectric substrate is investigated. The couplers have been produced employing a standard PCB process. The choice of the TACONIC RF-35 substrate as alternative to other conventional materials is motivated by its lower cost and high dielectric constant, allowing the reduc...

The successful design and measurement of high-performance coplanar waveguide (CPW) quadrature hybrid couplers integrated in MCM-D at Ku and Ka-band and Wilkinson power dividers at X-band are discussed in this work. The authors have investigated the feasibility of integrating 3-dB quadrature couplers in the MCM-D technology. Quadrature couplers based on two edge-coupled lines are not practical, ...

A new generation of Silicon-on-Insulator fiber-to-chip grating couplers which use a silicon overlay to enhance the directionality and thereby the coupling efficiency is presented. Devices are realized on a 200 mm wafer in a CMOS pilot line. The fabricated fiber couplers show a coupling efficiency of -1.6 dB and a 3 dB bandwidth of 80 nm.