Low-loss and low-crosstalk 8 × 8 arrayed waveguide grating (AWG) routers based on silicon nanowire waveguides are reported. A comparative study of the measurement results of the 3.2 nm-channel-spacing AWGs with three different designs is performed to evaluate the effect of each optimal technique, showing that a comprehensive optimization technique is more effective to improve the device performance than a single optimization. Based on the comprehensive optimal design, we further design and experimentally demonstrate a new 8-channel 0.8 nm-channel-spacing silicon AWG router for dense wavelength division multiplexing (DWDM) application with 130 nm CMOS technology. The AWG router with a channel spacing of 3.2 nm (resp. 0.8 nm) exhibits low insertion loss of 2.32 dB (resp. 2.92 dB) and low crosstalk of −20.5~-24.5 dB (resp. −16.9~-17.8 dB). In addition, sophisticated measurements are presented including all-input transmission testing and high-speed WDM system demonstrations for these routers. The functionality of the Si nanowire AWG as a router is characterized and a good cyclic rotation property is demonstrated. Moreover, we test the optical eye diagrams and bit-error-rates (BER) of the de-multiplexed signal when the multi-wavelength high-speed signals are launched into the AWG routers in a system experiment. Clear optical eye diagrams and low power penalty from the system point of view are achieved thanks to the low crosstalk of the AWG devices.

Here, we designed a broadband, low loss, compact, and fabrication-tolerant silicon-based four-mode edge coupler, composed of a 1×3 adiabatic mode-evolution counter-taper splitter and a triple-tip inverse taper. Based on mode conversion and power splitting, the proposed structure can simultaneously realize efficient mode coupling from TE0, TM0, TE1, and TM1 modes of multimode silicon waveguides to linearly polarized (LP), LP01,x, LP01,y, LP11a,x, and LP11a,y, modes in the few-mode fiber. To the best of our knowledge, we proposed the first scheme of four LP modes coupling, which is fully compatible with standard fabrication process. The 3D finite-difference time-domain simulation results show that the on-chip conversion losses of the four modes remain lower than 0.62 dB over the 200 nm wavelength range, and total coupling losses are 4.1 dB, 5.1 dB, 2.1 dB, and 2.9 dB for TE0-to-LP01,x, TM0-to-LP01,y, TE1-to-LP11a,x, and TM1-to-LP11a,y, respectively. Good fabrication tolerance and relaxed critical dimensions make the four-mode edge coupler compatible with standard fabrication process of commercial silicon photonic foundries.

We report the observation of a large-angle self-collimation phenomenon occurring in photonic crystals (PCs) composed of nanorods. Electromagnetic waves incident onto such PCs from directions covering a wide range of incident angles become highly localized along a single array of rods, which results in the narrow-beam propagation without divergence. A propagation length of 0.4 mm is experimentally observed over the wavelength ranging from 1540 nm to 1570 nm even in the large incident angle case, which is a very considerable length scale for on-chip optical interconnection.

We present the development of application-specific silicon-on-insulator SOI nanowire ring and racetrack resonators designed to assist semiconductor optical amplifier (SOA)-based all-optical wavelength conversion. We demonstrate the fabrication of fix resonance racetrack resonators exhibiting coupling gaps as low as 160 nm and tunable ring resonators with coupling gaps <; 90 nm. The resonators are cascaded after commercial 40 Gb/s SOAs to realize chirp filtering of the optical data signals through high-resolution spectral sampling. We experimentally demonstrate inverted and non-inverted SOI resonator-assisted all-optical wavelength conversion at 40 Gb/s and 160 Gb/s with power penalties <; 3 dB.

Wepropose and experimentally demonstrate the ultra-compact mode (de)multiplexers and polarization beam splitter (PBS) based on tapered bent asymmetric directional couplers. The strong coupling strength introduced by tapered bent waveguides significantly shortens the coupling length. As a result, high coupling and conversion efficiencies over a broad bandwidth can be obtained with small footprint. The coupling length of the fabricated PBS and mode (de)multiplexers are less than 4.9 μm and 8.7 μm, respectively. From 1534-1600 nm, the measured insertion loss (IL) is less than 1.4 and 1.55 dB for the TE ₁ -TE ₀ and TE ₂ -TE ₀ mode (de)multiplexers, respectively, and the crosstalk (CT) is less than −10 dB. The fabricated PBS shows low insertion loss of 0.55 dB and decent crosstalk of < −14 dB for both polarizations over an 85 nm wavelength range from 1505-1590 nm. Meanwhile, the larger fabrication tolerance ensures that the proposed devices can be readily fabricated with the standard complementary metal-oxide-semiconductor (CMOS) process.

We experimentally demonstrate a low-loss and low-crosstalk 16-channel 200 GHz-channel-spacing arrayed waveguide grating router (AWGR) with a size of 0.67 × 0.37 mm ² , targeting for C-band wavelength division multiplexing (WDM) interconnect routing applications. As a result, the AWGR features a channel spacing of 200±10 GHz, a free spectral range of 25.62 nm and a 3 dB channel bandwidth of 0.9 nm. Based on comprehensive optimal design, the measured characterization revealed 5.55 dB maximum channel loss non-uniformity with 1.13 dB best-case channel insertion loss. Besides, the fabricated device exhibits good cyclic-frequency operation for all 16 × 16 port combinations with channel crosstalk of –15.11 dB.