An Ultra-Compact Wavelength Diplexer Engineered by Subwavelength Grating

With the assistance of subwavelength grating (SWG), an ultra-compact multimode interference (MMI)-based diplexer is proposed. A certain number of SWG pitches are implemented in the middle of the MMI section, which can engineer the effective refractive index for the modes and, therefore, tune the beat length. With proper tailoring of the grating parameters, the beat lengths of the two wavelengths can be reduced as well as the device length, which has to match several odd or even times of beat lengths of both wavelengths. As a result, the proposed wavelength diplexer is $43.4~\mu \text{m}$ in length, which is only ~30% of its conventional counterpart. It also displays a wide 1-dB bandwidth of ~150 nm around the wavelength of 1310 and ~120 nm around the wavelength of 1550 nm. The insertion losses are less than 0.1 dB for the two operating wavelengths while the extinction ratios are both better than 20 dB.

[1]  Zhiping Zhou,et al.  An ultra-compact MMI-based wavelength diplexer employing subwavelength grating , 2017, 2017 IEEE 14th International Conference on Group IV Photonics (GFP).

[2]  H. Tsang,et al.  Fully suspended slot waveguides for high refractive index sensitivity. , 2017, Optics letters.

[3]  Zhiping Zhou,et al.  Manipulation of beat length and wavelength dependence of a polarization beam splitter using a subwavelength grating. , 2016, Optics letters.

[4]  Zhiping Zhou,et al.  Refractive index engineering of high performance coupler for compact photonic integrated circuits , 2016 .

[5]  Jinbiao Xiao,et al.  Ultracompact and Broadband Silicon-Based Strip-to-Slot Mode Converter , 2016, IEEE Photonics Technology Letters.

[6]  Zhiping Zhou,et al.  Subwavelength-grating-assisted broadband polarization-independent directional coupler. , 2016, Optics letters.

[7]  Alexander Y. Piggott,et al.  Inverse design and demonstration of a compact and broadband on-chip wavelength demultiplexer , 2015, Nature Photonics.

[8]  Siegfried Janz,et al.  Waveguide sub‐wavelength structures: a review of principles and applications , 2015 .

[9]  Michael Hochberg,et al.  Design and optimization of a novel silicon-on-insulator wavelength diplexer. , 2014, Optics express.

[10]  I Molina-Fernández,et al.  Wavelength independent multimode interference coupler. , 2013, Optics express.

[11]  Siegfried Janz,et al.  An ultra‐compact multimode interference coupler with a subwavelength grating slot , 2013 .

[12]  Xingjun Wang,et al.  Ultra-short silicon MMI duplexer , 2012, Photonics Asia.

[13]  K. Bergman,et al.  Colorless Optical Network Unit Based on Silicon Photonic Components for WDM PON , 2012, IEEE Photonics Technology Letters.

[14]  Siegfried Janz,et al.  Subwavelength grating periodic structures in silicon-on-insulator: a new type of microphotonic waveguide. , 2010, Optics express.

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

[16]  M. Rasras,et al.  Diplexer With Integrated Filters and Photodetector in Ge–Si Using $\Gamma-{X}$ and $\Gamma-{M}$ Directions in a Grating Coupler , 2009, IEEE Photonics Technology Letters.

[17]  Sailing He,et al.  Design of a Polarization Insensitive Triplexer Using Directional Couplers Based on Submicron Silicon Rib Waveguides , 2009, Journal of Lightwave Technology.

[18]  Roel Baets,et al.  Silicon-on-insulator ultra-compact duplexer based on a diffractive grating structure. , 2007, Optics express.

[19]  Xu Liu,et al.  Design of an ultracompact MMI wavelength demultiplexer in slot waveguide structures. , 2007, Optics express.

[20]  P. Cheben,et al.  Subwavelength waveguide grating for mode conversion and light coupling in integrated optics. , 2006, Optics express.

[21]  Andrew W. Lee,et al.  Slotted multimode-interference devices. , 2004, Applied optics.

[22]  E. Palik Handbook of Optical Constants of Solids , 1997 .

[23]  Timothy J. Drabik,et al.  Optimized binary, phase-only, diffractive optical element with subwavelength features for 1.55 μm , 1995 .

[24]  Mahmoud Rasras,et al.  Diplexer With Integrated Filters and Photodetector in Ge-Si Using and Directions , 2009 .

[25]  E.C.M. Pennings,et al.  Optical multi-mode interference devices based on self-imaging: principles and applications , 1995 .