Zanyun Zhang

CMOS-Compatible Vertical Grating Coupler With Quasi Mach–Zehnder Characteristics

A vertical grating coupler on silicon-on-insulator substrates has been designed and demonstrated. The light from a vertical fiber can be coupled in and split equally into two arms with the fiber placed in the grating center. An optical combiner is used to collect the transmission from the two arms. The measured peak coupling efficiency is 37%. Our device can also function like a Mach-Zehnder interferometer. In a device with an arm difference of 30 μm, the normalized transmission spectra of 20-nm free spectral range and more than 12-dB extinction ratio at 1567 nm are obtained.

Monolithic Integration of Si 3 N 4 Microring Filters With Bulk CMOS IC Through Post-Backend Process

An experimental demonstration of backend monolithic integration of Si3N4 microring filter with bulk complementary metal-oxide-semiconductor (CMOS) integrated circuit (IC) is accomplished using CMOS postbackend process. Si3N4 photonic layer is integrated on the top surface of CMOS IC die which is manufactured in commercial CMOS foundry. The Si3N4 microring filters in photonic layer are fabricated using CMOS postbackend process with only two additional lithography steps. The filters can be thermally tuned by microheaters integrated in CMOS circuits, which are controlled by transmission gates. A measured optical transmission spectrum and a dynamic characteristic of the integrated filter are provided.

Bidirectional grating coupler based optical modulator for low-loss Integration and low-cost fiber packaging

We proposed and demonstrated a novel optical modulator based on a bidirectional grating coupler designed for perfectly vertical fiber coupling. The grating functions as the fiber coupler and 3-dB splitter. To observe the interference, an arm difference of 30μm is introduced. As a result of the high coupling efficiency and near perfect split ratio of the grating coupler, this device exhibits a low on-chip insertion loss of 5.4dB (coupling loss included) and high on-off extinction ratio more than 20dB. The modulation efficiency is estimated to be within 3-3.84V•cm. In order to investigate the fiber misalignment tolerance of this modulator, misalignment influence of the static characteristics is analyzed. 10Gb/s Data transmission experiments of this device are performed with different fiber launch positions. The energy efficiency is estimated to be 8.1pJ/bit.

Microwave photonic filter with reconfigurable and tunable bandpass response using integrated optical signal processor based on microring resonator

Abstract. A bandpass microwave photonic filter based on an integrated optical signal processor is proposed and demonstrated by numerical simulation. The optical signal processor consisting of double-bus-coupled and series-cascaded silicon microrings (MRs) is used to produce two bandpass responses to process optical carrier signal and sideband signal separately. Because of the tunability of MRs, variable −3  dB bandwidth and tunable operating frequency are achieved. The −3  dB bandwidth and operating frequency can be tuned from 1.5 to 12 GHz and from 15 to 34 GHz, respectively. The loss impact, tuning method, and fabrication error tolerance are also discussed.

CMOS image sensor with optimal video sampling scheme

Time-varying illumination on the focal plane is a three-dimensional signal. Multidimensional sampling theory proves that the temporal resolution can be optimally improved by a factor of

CMOS monolithic optoelectronic integrated circuit for on-chip optical interconnection

\sqrt 2

Demonstration of Quasi Mach-Zehnder optical modulator based on perfectly vertical fiber grating coupler

while the spatial resolution is reserved by changing the sampling scheme. Based on the theory, a prototype multi-field CMOS image sensor (CIS) is designed for a 0.35-μm 2P4M CMOS process. Corresponding pixels in 4×4-pixel clusters are assembled into 16 fields over the whole array. Control pins (resets and shutters) of pixels are separated which provides the ability of sampling the illumination with the optimal sampling scheme.

Reconfigurable and tunable bandpass microwave photonic filters using integrated optical signal processor based on silicon microrings

Schottky barrier light emitting diode is designed and fabricated in CMOS technology. Stable Electro-luminescent emission is observed. The emission exhibits widespread spectral characteristics with nearly flatten peak in visible light range from 673nm to 785nm.