Abstract

Subwavelength nanostructure grating couplers fabricated on silicon-on-insulator substrates are used to simplify the fabrication process while maintaining high coupling efficiency. The main obstacle for their application in photonic integrated circuits is the small aperture size of the nanostructure when TE polarization is involved, since they are difficult to achieve with 193 nm deep-ultraviolet lithography and cause problems in inductively coupled plasma etching. A larger lateral period has been used to increase the aperture size. Here, we propose that decreasing the effective index of the nanostructure can also enlarge the aperture size. We analyze the two methods in detail with a rectangle-hole nanostructure and 220 nm thick waveguide layer, aiming at TE polarization centered at 1560 nm. We find performance degenerations for large lateral periods, and this can be simply compensated by adjusting the width of the rectangle hole. The minimum linewidth of the nanostructure can reach 240 nm, while the coupling efficiency is just slightly decreased. The backreflections of a large-aperture grating increase but stay in the same order with ordinary ones, and we also show that this can be overcome by apodizing the grating structure. Finally, we experimentally demonstrate the designed large-aperture grating couplers and the coupling efficiencies are higher than 35%, and reach a rectangle-hole width.

© 2016 Optical Society of America

Full Article  |  PDF Article
OSA Recommended Articles
Single-etch subwavelength engineered fiber-chip grating couplers for 1.3 µm datacom wavelength band

Daniel Benedikovic, Carlos Alonso-Ramos, Pavel Cheben, Jens H. Schmid, Shurui Wang, Robert Halir, Alejandro Ortega-Moñux, Dan-Xia Xu, Laurent Vivien, Jean Lapointe, Siegfried Janz, and Milan Dado
Opt. Express 24(12) 12893-12904 (2016)

Subwavelength index engineered surface grating coupler with sub-decibel efficiency for 220-nm silicon-on-insulator waveguides

Daniel Benedikovic, Pavel Cheben, Jens H. Schmid, Dan-Xia Xu, Boris Lamontagne, Shurui Wang, Jean Lapointe, Robert Halir, Alejandro Ortega-Moñux, Siegfried Janz, and Milan Dado
Opt. Express 23(17) 22628-22635 (2015)

High positional freedom SOI subwavelength grating coupler (SWG) for 300 mm foundry fabrication

Eng Wen Ong, Thomas Wallner, Nicholas M. Fahrenkopf, and Douglas D. Coolbaugh
Opt. Express 26(22) 28773-28792 (2018)

References

You do not have subscription access to this journal. Citation lists with outbound citation links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Figures (8)

You do not have subscription access to this journal. Figure files are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Tables (2)

You do not have subscription access to this journal. Article tables are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Equations (2)

You do not have subscription access to this journal. Equations are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Metrics

You do not have subscription access to this journal. Article level metrics are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription