A device that etches a periodic grating into a waveguide so that diffraction redirects light to couple with an optical fiber positioned above the chip. Its advantage is that optical testing is possible on the wafer before dicing, but its coupling bandwidth is narrow and it is polarization dependent.
Japanese name: グレーティングカプラ
Grating coupler appears in 2 practice questions across 1 topic, including Silicon photonics.
Field: Silicon photonics
Answer: C. It can be placed anywhere on the chip surface, and optical characteristics can be measured on the wafer by bringing a fiber down from above
A grating coupler forms periodic grooves (a diffraction grating) in the waveguide that diffract light obliquely upward to couple it to a fiber placed above. Waveguides need not be routed to the chip edge and measurements can be made on the wafer before dicing, so a major advantage is that many chips can easily be tested automatically. On the other hand, the diffraction condition depends on wavelength and polarization, so the coupling bandwidth is narrow, about a few tens of nm, it is hard to support more than one specific polarization, and its loss is generally higher than an edge coupler's. Coupling at the facet is what an edge coupler does.
Answer: C. It readily achieves low loss over a wide wavelength range, but requires facet processing and is hard to measure on the wafer
An edge coupler couples a waveguide routed out to the chip edge to a fiber butted against it from the side. Because it does not rely on diffraction, its wavelength dependence is small, making it easy to obtain low loss of about 1–2 dB or less over a wide band spanning the O-band and C-band, and it also handles different polarizations more easily. In exchange, the chip must be cut out and its facet finished cleanly, it can be placed only at the chip edge, and it is hard to launch light into it on the wafer before dicing. Being placeable anywhere on the surface and measurable on the wafer are features of the grating coupler.
A grating coupler forms periodic grooves (a diffraction grating) in the waveguide that diffract light obliquely upward to couple it to a fiber placed above.
Which is a correct advantage of a grating coupler for conne…Being placeable anywhere on the surface and measurable on the wafer are features of the grating coupler.
Which correctly describes an edge coupler, which couples to…As an Amazon Associate I earn from qualifying purchases.
Waveguide Dicing Edge coupler O-band C-band Chromatic dispersion CPO (co-packaged optics) Extinction ratio Mach-Zehnder modulator Plasma dispersion effect