Integrated heterodyne terahertz transceiver

DWPI Title: Microelectronics-based integrated heterodyne terahertz transceiver for e.g. passive detection in space and atmospheric science application, has quantum cascade laser coupling oscillator power to Schottky diode to mix with terahertz signal
Abstract: A heterodyne terahertz transceiver comprises a quantum cascade laser that is integrated on-chip with a Schottky diode mixer. A terahertz signal can be received by an antenna connected to the mixer, an end facet or sidewall of the laser, or through a separate active section that can amplify the incident signal. The quantum cascade laser couples terahertz local oscillator power to the Schottky diode to mix with the received terahertz signal to provide an intermediate frequency output signal. The fully integrated transceiver optimizes power efficiency, sensitivity, compactness, and reliability. The transceiver can be used in compact, fieldable systems covering a wide variety of deployable applications not possible with existing technology.
Use: Microelectronics-based integrated heterodyne terahertz transceiver for high-specificity, real-time, passive detection and high-specificity, real-time, active detection that is used in a differential absorption laser spectroscopy (DIAL) application, a field-deployable application or wideband application i.e. thermal imaging application such as space and atmospheric science application, molecular spectroscopy application, remote sensing application, biology application, medical imaging application, and communications application. Can also be used for short-range portal application to look through materials such as clothing or packaging materials for reflection and emission spectra, for mid-range applications of discriminating chemical and biological agents in a cloud, to multi-kilometer range exoatmospheric radar-type applications, used as a high-resolution spectroscopy tool for enhanced signature development, broad-band spectroscopy, and used as a diagnostic tool to monitor internal laser characteristics and an internal diagnostic tool to monitor quantum cascade laser (QCL) performance.
Advantage: The Schottky diode enables coherent detection for terahertz applications. The ransceiver optimizes power efficiency, sensitivity, compactness, and reliability, and can be efficiently applied in compact, fieldable systems covering a wide variety of deployable applications. The transceiver can be used as the power meter by responding to the signal directly, without mixing with the local oscillator. The transceiver achieves successful integration of terahertz sources and detectors on a single chip, along with cooling, optics and control electronics, while maintaining high source power greater than 10 mW, detection sensitivity, and operating temperatures, in a compact, reliable, integrated package. The transceiver is provided with an IF circuit to process a mixer output, so that the diode detects terahertz radiation within a limited bandwidth around frequency, and is insensitive to signals at frequencies outside a bandwidth, thus rejecting noise outside a detection bandwidth. The transceiver utilizes monolithic integration of the QCL and the diode to form a simple and generically useful terahertz photonic integrated circuit. The transceiver simplifies ability to phase lock by eliminating optical coupling between physically separate components. The transceiver utilizes IF frequency of a locked system observed to drift less than 10 Hz over a period of 5 to 10 minutes, such that the diode can be used to control differential mode frequency characteristics of the QCL with a very high degree of precision.
Novelty: The transceiver has a quantum cascade laser (QCL) (22) comprising a layered heterostructure of semiconductor alloys on a bottom contact layer (29), and a top waveguide layer (28) on the layered heterostructure to provide an active semiconductor core (23) between the top layer and the bottom layer. A Schottky diode (27) comprises a rectifying metal contact on a top surface of the layered heterostructure. The QCL couples terahertz local oscillator power to the Schottky diode to mix with a received terahertz signal (15) to provide an intermediate frequency (IF) output signal.
Filed: 6/22/2009
Application Number: US2009488612A
Tech ID: SD 11423.0
This invention was made with Government support under Contract No. DE-NA0003525 awarded by the United States Department of Energy/National Nuclear Security Administration. The Government has certain rights in the invention.
Data from Derwent World Patents Index, provided by Clarivate
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