An official website of the United States government
Abstract—The efficiency of Electro-Optic Modulators (EOM) is directly related to how the rf signal is imposed onto the optical signal. Other factors affecting this efficiency are: the selected architecture and the Electro-Optic materials responsible for modulation through the Electro-Optic Effect. In this paper we demonstrate a millimeter wave antenna integrated EOM that operates at 94 GHz. To improve efficiency, the antenna is integrated directly onto the active region of the electro-optic effect based EOM. Notably, conventional antennas had to be modified to achieve a feed port that is best suited for the selected EOM architecture. For the antenna design optimization, we devised a design procedure that is more suitable for these type of devices. We proposed a design methodology that insures an optimum Field Enhancement (FE) that is responsible for modulation. A novel overall EOM architecture that promotes increased efficiency that makes use of the inherently lossy EO material only where needed in the optical link by making use of an adiabatic transition from a passive Optical waveguide to active portion of the optical link.
more »
« less
Integrated Planar Antenna with High Field Enhancement for On-Chip Electro-Optical Modulator Design
On chip antennas with integrated electro-optic modulators (EOMs) are attractive for millimeter wave applications. Such EOMs are placed at the antenna feed and enable the mixing of the incoming millimeter wave (mm-wave) signal with an optical carrier. As such, the mm-wave capture is turned into an optical signal that can be easily processed for imaging using standard infrared cameras. Our proposed on-chip antenna with the EOM modulator operated at 94 GHz or 77 GHz, with the antenna tuned at that frequency. For high modulation efficiency, it is critical that the modulator region is as small as possible with the optical waveguide leading to the EOM, also being well-matched. Notably, the enhanced field at the antenna feed leads to higher modulation efficiency and sensitivity. Therefore, an optimum antenna design must hasve as large as possible field strength at the feed.
more »
« less
- Award ID(s):
- 1809728
- PAR ID:
- 10271613
- Date Published:
- Journal Name:
- 2020 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
A high-gain SIW elliptically polarized antenna combination of a dipole and loop antenna based on substrate-integrated waveguide (SIW) is proposed for millimeter-wave (mm-wave) applications. The dipole and loop antenna are differentially excited by a longitudinal slot etched on the top layer of SIW. The proposed combination of dipole and loop antenna forms a parallel electric dipole and magnetic dipole, which radiates two orthogonal electric field components and 90∘ phase difference in the far-field radiation when they are excited with the same phased signal. The proposed antenna achieves a realized gain of 8.346 dBi, with a radiation efficiency of 89.40% at 60 GHz.more » « less
-
This paper presents a single-fed, single-layer, dual-band antenna with a large frequency ratio of 4.74:1 for vehicle-to-vehicle communication. The antenna consists of a 28 GHz inset-fed rectangular patch embedded into a 5.9 GHz patch antenna for dual-band operation. The designed dual-band antenna operates from 5.81 to 5.99 GHz (Dedicated Short Range Communications, DSRC) and 27.9 to 30.1 GHz (5G millimeter-wave (mm-wave) band). Furthermore, the upper band patch was modified by inserting slots near the inset feed line to achieve an instantaneous bandwidth of 4.5 GHz. The antenna was fabricated and measured. The manufactured prototype operates simultaneously from 5.8 to 6.05 GHz and from 26.8 to 31.3 GHz. Notably, the designed dual-band antenna offers a high peak gain of 7.7 dBi in the DSRC band and 6.38 dBi in the 5G mm-wave band.more » « less
-
We propose an on-chip triply resonant electro-optic modulator architecture for RF-to-optical signal conversion and provide a detailed theoretical analysis of the optimal “circuit-level” device geometries and their performance limits. The designs maximize the RF-optical conversion efficiency through simultaneous resonant enhancement of the RF drive signal, a continuous-wave (CW) optical pump, and the generated optical sideband. The optical pump and sideband are resonantly enhanced in respective supermodes of a two-coupled-cavity optical resonator system, while the RF signal can be enhanced in addition by an LC circuit formed by capacitances of the optical resonator active regions and (integrated) matching inductors. We show that such designs can offer 15-50 dB improvement in conversion efficiency over conventional microring modulators. In the proposed configurations, the photon lifetime (resonance linewidth) limits the instantaneous RF bandwidth of the electro-optic response but does not limit its central RF frequency. The latter is set by the coupling strength between the two coupled cavities and is not subject to the photon lifetime constraint inherent to conventional singly resonant microring modulators. This feature enables efficient operation at high RF carrier frequencies without a reduction in efficiency commonly associated with the photon lifetime limit and accounts for 10-30 dB of the total improvement. Two optical configurations of the modulator are proposed: a “basic” configuration with equal Q-factors in both supermodes, most suitable for narrowband RF signals, and a “generalized” configuration with independently tailored supermode Q-factors that supports a wider instantaneous bandwidth. A second significant 5-20 dB gain in modulation efficiency is expected from RF drive signal enhancement by integrated LC resonant matching, leading to the total expected improvement of 15-50 dB. Previously studied triply-resonant modulators, with coupled longitudinal (across the free spectral range (FSR)) modes, have large resonant mode volume for typical RF frequencies, which limits the interaction between the optical and RF fields. In contrast, the proposed modulators support maximally tightly confined resonant modes, with strong coupling between the mode fields, which increases and maintains high device efficiency across a range of RF frequencies. The proposed modulator architecture is compact, efficient, capable of modulation at high RF carrier frequencies and can be applied to any cavity design or modulation mechanism. It is also well suited to moderate Q, including silicon, implementations, and may be enabling for future CMOS RF-electronic-photonic systems on chip.more » « less
-
Zmuidzinas, Jonas; Gao, Jian-Rong (Ed.)Polarization modulation is a powerful technique to increase the stability of measurements by enabling the distinction of a polarized signal from dominant slow system drifts and unpolarized foregrounds. Furthermore, when placed as close to the sky as possible, modulation can reduce systematic errors from instrument polarization. In this work, we introduce the design and preliminary drive system laboratory performance of a new 60 cm diameter reflective half-wave plate (RHWP) polarization modulator. The wave plate consists of a wire array situated in front of a flat mirror. Using 50 μm diameter wires with 175 μm spacing, the wave plate will be suitable for operation in the millimeter wavelength range with flatness of the wires and parallelism to the mirror held to a small fraction of a wavelength. The presented design targets the 77-108 GHz range. Modulation is performed by a rotation of the wave plate with a custom rotary drive utilizing an actively controlled servo motor.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Conference Paper:
- The DOI is not currently available.
