Broadband 1 × 3 Couplers With Variable Splitting Ratio Using Cascaded Step-Size MMI

In this paper, we propose and fabricated a novel scheme of SOI-based 1 × 3 coupler with variable splitting ratio. The coupler consists of two cascaded MMI with different sizes, and a wide range of splitting ratios from 1:0.1:1 to 1:18:1 can be achieved by modifying the size of the first-step MMI. Using the structure of cascaded step-size MMI, this kind of device has a compact footprint of below 15 μm × 15 μm and simple fabrication process. Meanwhile, the simulation analyses prove that the proposed couplers have a large operation bandwidth above 60 nm and be robust to the fabrication errors. Couplers with several splitting ratios were fabricated and well measured. Based on the measurement results, the splitting ratios of fabricated couplers from 1:0.67:1 to 1:18:1 can be achieved, and stable performance with the transmission efficiencies above 80% can be maintained over 50 nm wavelength range, which is the largest operation bandwidth to the best of our knowledge.

[1]  Lars Thylén,et al.  Integrated photonics in the 21st century , 2014 .

[2]  Zhiping Zhou,et al.  Arbitrary-ratio 1 × 2 power splitter based on asymmetric multimode interference. , 2014, Optics letters.

[3]  H. Melchior,et al.  with Free Selection of Power Splitt , 1996 .

[4]  T. Chang,et al.  Waveguide couplers with new power splitting ratios made possible by cascading of short multimode interference sections. , 2007, Optics express.

[5]  Deming Kong,et al.  Integrated In-Band OSNR Monitor Based on Asymmetrical Parallel-MZIs for WDM signals , 2016, IEEE Journal of Selected Topics in Quantum Electronics.

[6]  H. Melchior,et al.  New 2/spl times/2 and 1/spl times/3 multimode interference couplers with free selection of power splitting ratios , 1996 .

[7]  Chongxiu Yu,et al.  Resolution-enhanced all-optical analog-to-digital converter employing cascade optical quantization operation. , 2014, Optics express.

[8]  Pascual Munoz,et al.  Arbitrary Coupling Ratio Multimode Interference Couplers in Silicon-on-Insulator , 2014, Journal of Lightwave Technology.

[9]  Hui Li,et al.  1×3 optical drop splitter in a rod-type silicon photonic crystal , 2011, 2011 Asia Communications and Photonics Conference and Exhibition (ACP).

[10]  H Melchior,et al.  General self-imaging properties in N × N multimode interference couplers including phase relations. , 1994, Applied optics.

[11]  Nan Zhang,et al.  Integrated photonic power divider with arbitrary power ratios. , 2017, Optics letters.

[12]  Daoxin Dai,et al.  Silicon mode (de)multiplexer enabling high capacity photonic networks-on-chip with a single-wavelength-carrier light. , 2013, Optics letters.

[13]  H Melchior,et al.  Overlapping-image multimode interference couplers with a reduced number of self-images for uniform and nonuniform power splitting. , 1995, Applied optics.

[14]  Min Zhang,et al.  1x3 beam splitter for TE polarization based on self-imaging phenomena in photonic crystal waveguides. , 2010, Optics express.

[15]  Kuanping Shang,et al.  Silicon nitride tri-layer vertical Y-junction and 3D couplers with arbitrary splitting ratio for photonic integrated circuits. , 2017, Optics express.

[16]  T. Aalto,et al.  Unconstrained splitting ratios in compact double-MMI couplers. , 2014, Optics express.

[17]  J. Leuthold,et al.  Multimode interference couplers with tunable power splitting ratios , 2001 .