Continuously apodized fiber-to-chip surface grating coupler with refractive index engineered subwavelength structure.

We demonstrate a fully etched, continuously apodized fiber-to-chip surface grating coupler for the first time (to our knowledge). The device is fabricated in a single-etch step and operates with TM-polarized light, achieving a coupling efficiency of 3.7 dB and a 3 dB bandwidth of 60 nm. A subwavelength microstructure is employed to generate an effective medium engineered to vary the strength of the grating and thereby maximize coupling efficiency, while mitigating backreflections at the same time. Minimum feature size is 100 nm for compatibility with deep-UV 193 nm lithography.

[1]  Siegfried Janz,et al.  Waveguide grating coupler with subwavelength microstructures. , 2009, Optics letters.

[2]  Lech Wosinski,et al.  Highly efficient nonuniform grating coupler for silicon-on-insulator nanophotonic circuits. , 2010, Optics letters.

[3]  S. Janz,et al.  A broad-band waveguide grating coupler with a subwavelength grating mirror , 2006, IEEE Photonics Technology Letters.

[4]  R. Soref,et al.  The Past, Present, and Future of Silicon Photonics , 2006, IEEE Journal of Selected Topics in Quantum Electronics.

[5]  P Waldron,et al.  A high-resolution silicon-on-insulator arrayed waveguide grating microspectrometer with sub-micrometer aperture waveguides. , 2007, Optics express.

[6]  A. Delage,et al.  Folded cavity SOI microring sensors for high sensitivity and real time measurement of biomolecular binding. , 2008, Optics express.

[7]  R. Baets,et al.  High efficiency diffractive grating couplers for interfacing a single mode optical fiber with a nanophotonic silicon-on-insulator waveguide circuit , 2008 .

[8]  Siegfried Janz,et al.  Refractive index engineering with subwavelength gratings for efficient microphotonic couplers and planar waveguide multiplexers. , 2010, Optics letters.

[9]  H. Tsang,et al.  Nanoholes Grating Couplers for Coupling Between Silicon-on-Insulator Waveguides and Optical Fibers , 2009, IEEE Photonics Journal.

[10]  Theodor Tamir,et al.  Analysis and Design of Grating Couplers , 1980 .

[11]  R. Baets,et al.  Compact efficient broadband grating coupler for silicon-on-insulator waveguides. , 2004, Optics letters.

[12]  Siegfried Janz,et al.  Demultiplexer with blazed waveguide sidewall grating and sub-wavelength grating structure , 2008 .

[13]  Minhao Pu,et al.  High-efficiency, large-bandwidth silicon-on-insulator grating coupler based on a fully-etched photonic crystal structure , 2010 .