Keqi Ma

5 x 20 Gb/s heterogeneously integrated III-V on silicon electro-absorption modulator array with arrayed waveguide grating multiplexer

We present a five-channel wavelength division multiplexed modulator module that heterogeneously integrates a 200 GHz channel-spacing silicon arrayed-waveguide grating multiplexer and a 20 Gbps electro-absorption modulator array, showing the potential for 100 Gbps transmission capacity on a 1.5x0.5 mm² footprint.

Experimental Demonstration of Single Mode- Splitting in Microring With Bragg Gratings

We demonstrate single mode-splitting in two types of microring resonators with Bragg gratings. In the first device type, gratings are periodically embedded to the inner wall of the microring resonator. By adjusting the reflection coefficient of the grating and the self-coupling coefficient between the waveguide and microring, experimental results show that the distance between the splitting dips can vary from 0 to more than 1 nm. In the second device type, Bragg gratings break into two identical parts with a π phase shift between them. The center peak in the mode-splitting spectrum has a full-width at half-maximum of 0.1 nm. The spectra can also be a Fano-type transmission, when the phase shift deviates from π.

Low driving voltage band-filling-based III-V-on-silicon electroabsorption modulator

In this paper, a method for realizing a low driving voltage electroabsorption modulator based on the band-filling effect is demonstrated. The InP-based electroabsorption modulator is integrated using divinylsiloxane-bis-benzocyclobutene adhesive bonding on a silicon-on-insulator waveguide platform. When the electroabsorption modulator is forward biased, the band-filling effect occurs, which leads to a blue shift of the exciton absorption spectrum, while the absorption strength stays almost constant. In static operation, an extinction ratio of more than 20 dB with 100 mV bias variation is obtained in an 80 μm long device. In dynamic operation, 1.25 Gbps modulation with a 6.3 dB extinction ratio is obtained using only a 50 mV peak-to-peak driving voltage. The band-filling effect provides a method for realizing ultra-low-driving-voltage electroabsorption modulators.

Fabrication of all shallowly etched silicon reflection-type arrayed-waveguide gratings with one stigmatic point

We design, fabricate and measure an all shallowly etched reflection-type silicon arrayed waveguide gratings(R-AWG) with one stigmatic point, which contributes to reducing the crosstalk of R-AWG.

Design, optimization and fabrication of two-dimension high contrast subwavelength grating (HCG) mirror on Silicon-on-insulator

The high contrast grating (HCG) mirror has been illustrated and characterized. The investigated parameters including grating periods and filling factors were calculated by finite-difference time-domain method. The two-dimension HCG was fabricated by electron-beam lithography and inductively coupled plasma process. The reflectivity of the fabricated HCG mirror was measured, resulting in around 200 nm bandwidth. The measured result also showed a good agreement with calculated one. This achievement was promising in developing the novel light emitters in the telecommunication region.