Showing papers by "Leimeng Zhuang published in 2013"

Silicon nitride microwave photonic circuits

Abstract: We present an overview of several microwave photonic processing functionalities based on combinations of Mach-Zehnder and ring resonator filters using the high index contrast silicon nitride (TriPleXTM) waveguide technology. All functionalities are built using the same basic building blocks, namely straight waveguides, phase tuning elements and directional couplers. We recall previously shown measurements on high spurious free dynamic range microwave photonic (MWP) link, ultra-wideband pulse generation, instantaneous frequency measurements, Hilbert transformers, microwave polarization networks and demonstrate new measurements and functionalities on a 16 channel optical beamforming network and modulation format transformer as well as an outlook on future microwave photonic platform integration, which will lead to a significantly reduced footprint and thereby enables the path to commercially viable MWP systems

TriPleX waveguide platform: low-loss technology over a wide wavelength range

Abstract: In this article a selection of highlights of the TriPleX™ technology of LioniX is given. The basic waveguide technology is explained with recent benchmark measurements done by University California Santa Barbara (UCSB) and University Twente (UT-TE). In order to show the low loss transparency over a wide wavelength range three examples of applications in different wavelength regimes are described in more detail. These are the Integrated Laser Beam Combiner (ILBC) of XiO Photonics in the visible light, a ringresonator sensing platform of LioniX around 850 nm and a phased array antenna with an Optical Beam Forming Network in the 1550 nm band. Furthermore it is shown that the technology is easily accessible via Multi Project Wafer Runs for which the infrastructure and design libraries are also set up.

Novel low‐loss waveguide delay lines using Vernier ring resonators for on‐chip multi‐λ microwave photonic signal processors

Abstract: In this paper, novel photonic delay lines (DLs) using Vernier/non-identical ring resonators (VRRs) are proposed and demonstrated, which are capable of simultaneous generation of multiple different delays at different wavelengths (frequencies). The simple device architectures and full reconfigurability allow the DLs to be integrated with other functional building blocks in photonic integrated circuits to realize on-chip, complex multi-λ microwave photonic signal processors with reduced system complexity. To prove the concept, DLs using VRRs in cascaded and coupled configurations have been fabricated in TriPleXTM waveguide technology, which enables a very low delay-induced loss of approximately 0.18 dB/100 ps. The fabricated DLs demonstrated simultaneous generation of four incremental delays, where a maximum incremental step of 550 ps and a corresponding top delay of 1650 ps were measured for a bandwidth up to 1 GHz. To our knowledge, this is the first report on VRRs for delay generation functionalities.

Novel wideband microwave polarization network using a fully-reconfigurable photonic waveguide interleaver with a two-ring resonator-assisted asymmetric Mach-Zehnder structure

Abstract: We propose and demonstrate a novel wideband microwave photonic polarization network for dual linear-polarized antennas. The polarization network is based on a waveguide-implemented fully-reconfigurable optical interleaver using a two-ring resonator-assisted asymmetric Mach-Zehnder structure. For microwave photonic signal processing, this structure is able to serve as a wideband 2 × 2 RF coupler with reconfigurable complex coefficients, and therefore can be used as a polarization network for wideband antennas. Such a device can equip the antennas with not only the polarization rotation capability for linear-polarization signals but also the capability to operate with and tune between two opposite circular polarizations. Operating together with a particular modulation scheme, the device is also able to serve for simultaneous feeding of dual-polarization signals. These photonic-implemented RF functionalities can be applied to wideband antenna systems to perform agile polarization manipulations and tracking operations. An example of such a interleaver has been realized in TriPleX waveguide technology, which was designed with a free spectral range of 20 GHz and a mask footprint of smaller than 1 × 1 cm. Using the realized device, the reconfigurable complex coefficients of the polarization network were demonstrated with a continuous bandwidth from 2 to 8 GHz and an in-band phase ripple of smaller than 5 degree. The waveguide structure of the device allows it to be further integrated with other functional building blocks of a photonic integrated circuit to realize on-chip, complex microwave photonic processors. Of particular interest, it can be included in an optical beamformer for phased array antennas, so that simultaneous wideband beam and polarization trackings can be achieved photonically. To our knowledge, this is the first-time on-chip demonstration of an integrated microwave photonic polarization network for dual linear-polarized antennas.

Integrated Photonic ${\rm K}_{\rm u}$ -Band Beamformer Chip With Continuous Amplitude and Delay Control

Abstract: We present the first demonstration of a broadband and continuously tunable integrated optical beamforming network (IOBFN) capable of providing continuously tunable true-time-delay up to 236 ps over the entire DVB-S band (10.7-12.75 GHz), realized with a CMOS compatible process. The tunable delays are based on reconfigurable optical ring resonators in conjunction with a single optical sideband filter integrated on the same optical chip. The delays and filter responses are software programmable. Four tunable delay lines are integrated on a single chip and configured to feed a 16-element linear antenna array. The broadband beam steering capability of the proposed IOBFN is demonstrated by the squint-free antenna pattern generated from the measured RF amplitude and phase responses of the optical delay line.

Ring resonator-based on-chip modulation transformer for high-performance phase-modulated microwave photonic links

Abstract: In this paper, we propose and experimentally demonstrate a novel wideband on-chip photonic modulation transformer for phase-modulated microwave photonic links. The proposed device is able to transform phase-modulated optical signals into intensity-modulated versions (or vice versa) with nearly zero conversion of laser phase noise to intensity noise. It is constructed using waveguide-based ring resonators, which features simple architecture, stable operation, and easy reconfigurability. Beyond the stand-alone functionality, the proposed device can also be integrated with other functional building blocks of photonic integrated circuits (PICs) to create on-chip complex microwave photonic signal processors. As an application example, a PIC consisting of two such modulation transformers and a notch filter has been designed and realized in TriPleX TM waveguide technology. The realized device uses a 2 × 2 splitting circuit and 3 ring resonators with a free spectral range of 25 GHz, which are all equipped with continuous tuning elements. The device can perform phase-to-intensity modulation transform and carrier suppression simultaneously, which enables high-performance phase-modulated microwave photonics links (PM-MPLs). Associated with the bias-free and low-complexity advantages of the phase modulators, a single-fiber-span PM-MPL with a RF bandwidth of 12 GHz (3 dB-suppression band 6 to 18 GHz) has been demonstrated comprising the proposed PIC, where the achieved spurious-free dynamic range performance is comparable to that of Class-AB MPLs using low-biased Mach-Zehnder modulators.

Ring resonator-based on-chip PM-IM convertor for high-performance microwave photonic links

Abstract: We propose and demonstrate a novel wideband photonic PM-IM convertor for performance improvement of phase-modulated microwave photonic links, which uses a simple architecture based on ring resonators. The full programmability of the proposed device allows arbitrary optical amplitude and phase manipulations required for broadband PM-IM conversion. Moreover, the device can be integrated with other functional building blocks in photonic integrated circuits to realize on-chip complex microwave photonic signal processors.

On-chip, CMOS-compatible, hardware-compressive integrated photonic beamformer based on WDM

Abstract: We propose and experimentally demonstrate a novel, hardware-compressive architecture for broadband and continuously tunable integrated optical true-time-delay beamformers. The architecture is based on on-chip wavelength division multiplexing (WDM) that, in conjunction with the frequency-periodic response of optical ring resonator (ORR) filters, dramatically reduces the network complexity and, in turn, its area occupation on the wafer. This allows the integration of an unprecedented number of delay channels on a single chip, overcoming the main limitation of current integrated beamformers, that is, the limited capability to feed very large arrays when using a single chip. Based on this technique, a novel device is realized with TriPleXTM waveguide technology, using CMOS-compatible fabrication equipment, and its functionality is demonstrated over the instantaneous 2-10 GHz bandwidth. At the best of our knowledge, this results represent at the same time the record instantaneous bandwidth (8 GHz) for an optical beamformer based on optical ring resonators (ORR), and the first demonstration of an integrated beamformer where signals from different antenna elements are processed simultaneously by individual delay lines, exploiting the periodic response of ORRs.

Waveguide filter-based on-chip differentiator for microwave photonic signal processing

Abstract: We propose and demonstrate a waveguide filter-based on-chip differentiator for microwave photonic signal processing. The system principle allows the operation of arbitrary-order differentiation. The realized device is constructed using the basic building blocks of photonic integrated circuits, and features scalability and full reconfigurability. The waveguide architecture allows this functionality to be incorporated in more complex on-chip signal processing systems, which manifests the potentials of a fully integrated microwave photonic signal transmitter.

Integrated microwave photonic signal processors in TriPleX TM waveguide

Abstract: Microwave photonics (MWP) merges optical components and subsystems with RF engineering. As an emerging technology, it enables realization of complex RF functionalities beyond the capability of the current all-electronics systems. In the investigations of the recent decades, the advantages of MWP systems such as large instantaneous bandwidth, RF frequency transparency, flexible tunability and reconfigurability, and less susceptibility to electromagnetic interference, have been harnessed to realize various RF functionalities. Among them, the well-known include signal generation, signal transmission and distribution, signal processing, control, signal measurement and analysis. This technology opens new perspectives for information and communication systems and networks, and it also creates possibilities for new RF applications in both niche and consumer markets. From the industrial perspective, however, the success of MWP solutions, with respect to the conventional all-electronics solutions, is believed to be determined by the progress of photonic integration, where the optical components and subsystems are incorporated in photonic integrated circuits (PICs) [1]. Compared to the MWP systems constructed using discrete optical components, the PIC-based MWP systems, or termed as integrated microwave photonics (IMWP), feature higher robustness and compactness, smaller SWaP, and most importantly, the potential of large reduction on system cost.