Quasi-free-space optical coupling between diffraction grating couplers fabricated on independent substrates

Mule, A.V.; Villalaz, Ricardo A.; Gaylord, Thomas K.; Meindl, J.D.

doi:10.1364/ao.43.005468

Cited by 10 publications

(7 citation statements)

References 18 publications

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“…Only a limited number of papers have discussed grating-to-grating coupling. The first preferential-order optical couplers on different substrates were demonstrated in [21], but this work utilized volume gratings, and no optimization process was provided. Compared with volume gratings, surface-relief gratings have reduced the thickness and improved process integration, thus becoming a popular solution in compact interconnect technology.…”

Section: Introductionmentioning

confidence: 99%

Grating design for interlayer optical interconnection of in-plane waveguides

2016

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Interlayer grating-to-grating optical interconnect coupling efficiency is simulated and optimized using rigorous coupled-wave analysis (RCWA) for the case of binary rectangular-groove gratings. The "equivalent index slab (EIS)" concept is proposed to alleviate the numerical sensitivity problem inherent in the RCWA-leaky-wave approach, making the method applicable to any multilayer structure that has an arbitrary grating profile, large refractive-index differences, and a limited grating length. The method is easy to implement and computationally efficient and can provide optimal designs based on the system designer's need. To determine the viability of the RCWA-EIS approach, results are compared to those obtained using the finite-difference time-domain method, and an excellent agreement is found.

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Section: Introductionmentioning

confidence: 99%

Grating design for interlayer optical interconnection of in-plane waveguides

2016

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“…However, the compliance can be adjusted by using thinner metal leads. guided-wave polymer pillar-based I/Os [5], where an optical signal, generated on the chip or off-chip, is transported through a polymer pillar to or from the chip; quasi-free space diffraction grating I/Os [88], where waveguides terminating in diffractive elements, which bend the light in a surface normal direction, are fabricated on the board and the chip;…”

Section: Vertical Compliance Measurementsmentioning

confidence: 99%

Probe Module for Wafer-Level Testing of Gigascale Chips With Electrical and Optical I/O Interconnects

Thacker

Ogunsola

Bakir

et al. 2005

Advances in Electronic Packaging, Parts A, B, and C

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The bandwidth provided by optical interconnects makes them an attractive solution for chip-to-package and chip-to-chip communications. In such systems, chips will have optical I/O interconnects fabricated alongside their conventional electrical counterparts. Virtually no work has been previously reported relating to the testing of such chips at the wafer-level. The requirements for probe hardware needed to achieve this are identified, and probe module configurations based on these requirements are presented. A high-density micro-opto-electro-mechanical-systems (MOEMS)-based probe substrate prototype for interfacing with chips having electrical and optical polymer pillar-based I/Os has been designed, and built using microfabrication techniques. Successful probing of an array of polymer pillar-based optical I/Os is reported.

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“…For chip-to-chip grating couplers, the lateral displacements of volume holographic gratings [1,2] and surface-relief gratings [3,4] have been experimentally studied. There is limited effort analyzing rotational misalignment, and such efforts all focus on rotations about the y-axis, or equivalently, changes in the incident angle [5,6]. Wu et al [7] analyzed the yaw, pitch, and roll rotation of a volume grating under vertical incidence (zero incident angle), but they only considered transmission through the grating instead of coupling into a waveguide.…”

Section: Introductionmentioning

confidence: 99%

Rigorous coupled-wave analysis equivalent-index-slab method for analyzing 3D angular misalignment in interlayer grating couplers

2016

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The interlayer waveguide grating coupling efficiencies under angular (rotational) misalignments are simulated using the 3D rigorous coupled-wave analysis (3D-RCWA) together with the RCWA equivalent-index-slab (RCWA-EIS) method. As examples of conical diffraction, rotations about the two coordinate axes, x and z, defined by the vectors [1 0 0] and [0 0 1], respectively, as well as an arbitrary axis, defined by the vector [2 2 1], are simulated for binary rectangular-groove gratings. The interlayer grating coupling efficiency is approximated by the product of the top- and bottom-grating diffraction efficiencies (DEs). It is found that the bottom-grating DEs decrease about 25% when the bottom grating is rotated ±0.1 rad (5.73°) about the z-axis. DEs slightly increase (5% to 10% depending on the grating structures) when the bottom grating is rotated ±0.1 rad about the x-axis. This is consistent with the diffraction behavior of an over-modulated grating. When the bottom grating is rotated about the vector [2 2 1], the change in DEs is asymmetric with a 100% decrease at a rotation angle -0.1 rad and a 67% decrease at a rotation angle +0.1 rad. The method is shown to be computationally efficient and numerically stable for grating structures with optimized parameters, and the resulting bottom-grating diffraction efficiencies demonstrate similar trends as those calculated by the 3D finite-difference time-domain simulations. The procedure presented can be directly used in the analysis and design of interlayer waveguide grating coupling for optical interconnects in high-density integrated electronics.

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Quasi-free-space optical coupling between diffraction grating couplers fabricated on independent substrates

Cited by 10 publications

References 18 publications

Grating design for interlayer optical interconnection of in-plane waveguides

Grating design for interlayer optical interconnection of in-plane waveguides

Probe Module for Wafer-Level Testing of Gigascale Chips With Electrical and Optical I/O Interconnects

Rigorous coupled-wave analysis equivalent-index-slab method for analyzing 3D angular misalignment in interlayer grating couplers

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