Yingtao Hu

25 Gbit/s silicon microring modulator based on misalignment-tolerant interleaved PN junctions

A high-speed depletion-mode silicon-based microring modulator with interleaved PN junctions optimized for high modulation efficiency and large alignment tolerance is demonstrated. It is fabricated using standard 0.18 μm complementary metal-oxide-semiconductor processes and provides low V(π)L(π)s of 0.68 V·cm to 1.64 V·cm with a moderate doping concentration of 2 × 10(17) cm(-3). The measured modulation efficiency decreases by only 12.4% under ± 150 nm alignment errors. 25 Gbit/s non-return-zero modulation with a 4.5 dB extinction ratio is experimentally realized at a peak-to-peak driving voltage of 2 V, demonstrating the excellent performance of the novel doping profile.

High speed silicon Mach-Zehnder modulator based on interleaved PN junctions

A high speed silicon Mach-Zehnder modulator is proposed based on interleaved PN junctions. This doping profile enabled both high modulation efficiency of V(π)L(π) = 1.5~2.0 V·cm and low doping-induced loss of ~10 dB/cm by applying a relatively low doping concentration of 2 × 10(17) cm(-3). High speed operation up to 40 Gbit/s with 7.01 dB extinction ratio was experimentally demonstrated with a short phase shifter of only 750 μm.

44-Gb/s Silicon Microring Modulators Based on Zigzag PN Junctions

We experimentally demonstrate silicon microring modulators with >;40-Gb/s modulation speed based on the carrier-depletion mechanism in reverse-biased PN junctions. A novel zigzag PN junction providing a modulation efficiency of 3.85× 10-5/V and a resistance-capacitance bandwidth of 51 GHz is proposed and demonstrated. The moderate Q factor of ~ 8000 and the operation wavelength detuning are optimized to relieve photon-lifetime-induced bandwidth limitation. Finally, with a voltage swing of 3 V, high-speed modulation of 20 and 44 Gb/s is experimentally demonstrated with the extinction ratio of 3.45 and 3.01 dB, showing great potential in the application of ultrahigh-capacity optical interconnects.

High-speed silicon modulator based on cascaded microring resonators

A high-speed silicon modulator based on cascaded double microring resonators is demonstrated in this paper. The proposed modulator experimentally achieved 40 Gbit/s modulation with an extinction ratio of 3.9 dB. Enhancement of the modulator achieves with an ultra-high optical bandwidth of 0.41 nm, corresponding to 51 GHz, was accomplished by using cascaded double ring structure. The described modulator can provides an ultra-high-speed optical modulation with a further improvement in electrical bandwidth of the device.

High-speed silicon-based microring modulators and electro-optical switches integrated with grating couplers

We demonstrate high-speed silicon-based microring modulators and electro-optical switches which are integrated with grating couplers. Wafer-level measurements are set up for the devices characterizations without wafer cleaving and facet polishing. 10 Gbit/s NRZ modulation is realized under pre-emphasis driving signals. Switch on / off time of 300 / 380ps are demonstrated in the asymmetrical 1×2 microring switch with an add-drop crosstalk of -23dB.

Misalignment-tolerant high-speed silicon microring modulator with interleaved p-n junctions

We present a high-speed silicon microring resonator with misalignment-tolerant interleaved p-n junctions. Moderate doping concentration of 2×10¹⁷ cm⁻³ results in a V<inf>π</inf>L of 0.98 V·cm and a total propagation loss of &#60; 17 dB/cm. 8 GHz modulation bandwidth and ∼ 30 GHz electric RC bandwidth are experimentally demonstrated.

Systematic investigation of coupling-modulated microring resonators based on interleaved p-n junctions

We systematically investigate the optical effects and the optical functions of coupling-modulated microring resonators (CMR) based on interleaved p-n junctions. The optical effect of coupling-induced frequency shifts (CIFS) is firstly observed experimentally. Due to the CIFS and thermal-optical effect, the resonance spacing is tuned as large as 0.182 nm (corresponding to 22.8 GHz), the extinction ratio is continuously modulated between 0 dB to as large as 35 dB.

Single-mode silicon-on-insulator elliptical microdisk resonators with high Q factors

We propose and demonstrate a novel elliptical microdisk resonator which enables single-mode operation with high quality (Q) factor. Such elliptical microdisk resonators with pedestal, which consist of plenty of smoothly changing bends with modified curvature radii, can easily achieve single-mode operation due to selective losses introduced by mode transmission mismatches and small curvature radii portion inside the elliptical microdisks. We fabricated the devices on silicon-on-insulator (SOI) platform. Single-mode resonance with high quality factor (Q) of ~105 was experimentally realized. Besides, the proposed elliptical microdisk provides larger coupling strength compared to normal circular microdisk, and hence enables critical coupling with easy-to-fabricate gaps.

Modeling and analysis of silicon-on-insulator elliptical microring resonators for future high-density integrated photonic circuits

We propose a novel resonator containing an elliptical microring based on a silicon-on-insulator platform. Simulations using the three-dimensional finite-difference time-domain method show that the novel elliptical microring can efficiently enhance the mode coupling between straight bus waveguides and resonator waveguides or between adjacent resonators while preserving relatively high intrinsic quality factors with large free spectral range. The proposed resonator would be an alternative choice for future high-density integrated photonic circuits.

Design, fabrication and characterization of cascaded SOI rib waveguide microring resonators

We demonstrate a three-stage double channel cascaded microrings integrated with grating couplers based on SOI rib waveguide. The resonant frequencies were well matched at the drop-port and still splitting at the through-port which was considered to be due to fabrication variations. Flat-top and broadened bandwidth were achieved in the three-stage microring device.