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All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Photonic Integrated Circuit TUned for Reconnaissance and Exploration (PICTURE)

The mid-infrared (MIR) spectral range (3-5 μm) is of particular interest for remotely sensing gaseous molecules such as H2O, CO2, CH4, N2O, CO, NH3, and other compounds. The infrared spectra of planets, moons, comets, and asteroids are rich in information, including gas composition and surface mineralogy. Significant advances in technology have emerged for ground-based telescopes, including the higher spectral resolution permitted by cross-dispersed instruments and heterodyne techniques. New technologies offer the opportunity to break this barrier, by using solid- state photonics. In the past three years, under the NASA ROSES PICASSO program, we have been developing key components for a revolutionary MIR spectrometer: Photonic Integrated Circuit TUned for Reconnaissance and Exploration (PICTURE), which is based on integrated photonics technology that offers ultra-small size, weight, and power (SWaP) with non-moving parts and low cost for future planetary missions. In this paper, we will describe our science and technology development progress leading to demonstrating the concept and functionalities of the PICTURE instrument. The photonic integrated circuit spectrometer (PICS) of the PICTURE instrument uses an integrated heterodyne detection scheme to significantly reduce SWaP and improve sensitivity. Our program goals are to advance the building blocks needed for the PICS, which include arrayed waveguide gratings (AWGs), quantum cascade lasers (QCLs) as local oscillators, and quantum cascade detectors (QCDs) as heterodyne detectors. In addition, we are leveraging a NASA SBIR program to develop the toolsets needed to fabricate MIR photonics lanterns (PL). The PL is a critical component that enables PICTURE to bring a signal from the collecting telescope to the PICS, which requires single optical mode inputs. PICTURE focuses on the CO spectral band at 4.6-4.8 μm that is of key importance to cometary science. We also continue to explore future instrument concepts that exploit the broad wavelength potential of the PICS design to perform spectroscopy spanning the full MIR and longwave IR (LWIR) bands. This will have wide applicability in planetary science, for example, to probe the strongest CO2, H2O, and CH4 transitions that are difficult (CH4) or impossible (CO2, H2O) to detect using Earth-based telescopes due to atmospheric opacity. Each integrated-photonics-spectrometer chip will feature a single heterodyne room-temperature laser with a wide wavelength tuning range, or multiple local-oscillator lasers for much broader spectral coverage. The fully developed PICTURE instrument will provide a cost-effective, high-resolution spectrometer for future space applications.

Anthony W Yu↗
NASA NTRSDate not supplied

Photonic Integrated Circuit TUned for Reconnaissance and Exploration (PICTURE)

The mid-infrared (MIR) spectral range (3-5 μm) is of particular interest for remotely sensing gaseous molecules such as H2O, CO2, CH4, N2O, CO, NH3, and other compounds. The infrared spectra of planets, moons, comets, and asteroids are rich in information, including gas composition and surface mineralogy. Significant advances in technology have emerged for ground-based telescopes, including the higher spectral resolution permitted by cross-dispersed instruments and heterodyne techniques. New technologies offer the opportunity to break this barrier, by using solid-state photonics. In the past three years, under the NASA ROSES PICASSO program, we have been developing key components for a revolutionary MIR spectrometer: Photonic Integrated Circuit TUned for Reconnaissance and Exploration (PICTURE), which is based on integrated photonics technology that offers ultra-small size, weight, and power (SWaP) with non-moving parts and low cost for future planetary missions. In this paper, we will describe our science and technology development progress leading to demonstrating the concept and functionalities of the PICTURE instrument. The photonic integrated circuit spectrometer (PICS) of the PICTURE instrument uses an integrated heterodyne detection scheme to significantly reduce SWaP and improve sensitivity. Our program goals are to advance the building blocks needed for the PICS, which include arrayed waveguide gratings (AWGs), quantum cascade lasers (QCLs) as local oscillators, and quantum cascade detectors (QCDs) as heterodyne detectors. In addition, we are leveraging a NASA SBIR program to develop the toolsets needed to fabricate MIR photonics lanterns (PL). The PL is a critical component that enables PICTURE to bring a signal from the collecting telescope to the PICS, which requires single optical mode inputs. PICTURE focuses on the CO spectral band at 4.6-4.8 μm that is of key importance to cometary science. We also continue to explore future instrument concepts that exploit the broad wavelength potential of the PICS design to perform spectroscopy spanning the full MIR and longwave IR (LWIR) bands. This will have wide applicability in planetary science, for example, to probe the strongest CO2, H2O, and CH4 transitions that are difficult (CH4) or impossible (CO2, H2O) to detect using Earth-based telescopes due to atmospheric opacity. Each integrated-photonics-spectrometer chip will feature a single heterodyne room-temperature laser with a wide wavelength tuning range, or multiple local-oscillator lasers for much broader spectral coverage. The fully developed PICTURE instrument will provide a cost-effective, high-resolution spectrometer for future space applications.

Anthony W Yu↗
NASA NTRSDate not supplied

Photonic Integrated Circuit TUned for Reconnaissance and Exploration (PICTURE)

The mid-infrared (MIR) spectral range (3-5 μm) is of particular interest for remotely sensing gaseous molecules such as H2O, CO2, CH4, N2O, CO, NH3, and other compounds. The infrared spectra of planets, moons, comets, and asteroids are rich in information, including gas composition and surface mineralogy. Significant advances in technology have emerged for ground-based telescopes, including the higher spectral resolution permitted by cross-dispersed instruments and heterodyne techniques. New technologies offer the opportunity to break this barrier, by using solid-state photonics. In the past three years, under the NASA ROSES PICASSO program, we have been developing key components for a revolutionary MIR spectrometer: Photonic Integrated Circuit TUned for Reconnaissance and Exploration (PICTURE), which is based on integrated photonics technology that offers ultra-small size, weight, and power (SWaP) with non-moving parts and low cost for future planetary missions. In this paper, we will describe our science and technology development progress leading to demonstrating the concept and functionalities of the PICTURE instrument. The photonic integrated circuit spectrometer (PICS) of the PICTURE instrument uses an integrated heterodyne detection scheme to significantly reduce SWaP and improve sensitivity. Our program goals are to advance the building blocks needed for the PICS, which include arrayed waveguide gratings (AWGs), quantum cascade lasers (QCLs) as local oscillators, and quantum cascade detectors (QCDs) as heterodyne detectors. In addition, we are leveraging a NASA SBIR program to develop the toolsets needed to fabricate MIR photonics lanterns (PL). The PL is a critical component that enables PICTURE to bring a signal from the collecting telescope to the PICS, which requires single optical mode inputs. PICTURE focuses on the CO spectral band at 4.6-4.8 μm that is of key importance to cometary science. We also continue to explore future instrument concepts that exploit the broad wavelength potential of the PICS design to perform spectroscopy spanning the full MIR and longwave IR (LWIR) bands. This will have wide applicability in planetary science, for example, to probe the strongest CO2, H2O, and CH4 transitions that are difficult (CH4) or impossible (CO2, H2O) to detect using Earth-based telescopes due to atmospheric opacity. Each integrated-photonics-spectrometer chip will feature a single heterodyne room-temperature laser with a wide wavelength tuning range, or multiple local-oscillator lasers for much broader spectral coverage. The fully developed PICTURE instrument will provide a cost-effective, high-resolution spectrometer for future space applications.

Anthony W. Yu↗
NASA NTRS2009

Compact, Miniature MMIC Receiver Modules for an MMIC Array Spectrograph

A single-pixel prototype of a W-band detector module with a digital back-end was developed to serve as a building block for large focal-plane arrays of monolithic millimeter-wave integrated circuit (MMIC) detectors. The module uses low-noise amplifiers, diode-based mixers, and a WR10 waveguide input with a coaxial local oscillator. State-of-the-art InP HEMT (high electron mobility transistor) MMIC amplifiers at the front end provide approximately 40 dB of gain. The measured noise temperature of the module, at an ambient temperature of 300 K, was found to be as low as 450 K at 95 GHz. The modules will be used to develop multiple instruments for astrophysics radio telescopes, both on the ground and in space. The prototype is being used by Stanford University to characterize noise performance at cryogenic temperatures. The goal is to achieve a 30-50 K noise temperature around 90 GHz when cooled to a 20 K ambient temperature. Further developments include characterization of the IF in-phase (I) and quadrature (Q) signals as a function of frequency to check amplitude and phase; replacing the InP low-noise amplifiers with state-of-the-art 35-nm-gate-length NGC low-noise amplifiers; interfacing the front-end module with a digital back-end spectrometer; and developing a scheme for local oscillator and IF distribution in a future array. While this MMIC is being developed for use in radio astronomy, it has the potential for use in other industries. Applications include automotive radar (both transmitters and receivers), communication links, radar systems for collision avoidance, production monitors, ground-penetrating sensors, and wireless personal networks.

Kangaslahti, Pekka P.↗
NASA NTRS1984

Atomic mean excitation energies for stopping powers from local plasma oscillator strengths

The stopping of a charged particle by isolated atoms is investigated theoretically using an 'atomic plasma' model in which atomic oscillator strengths are replaced by the plasma frequency spectrum. The plasma-frequency correction factor for individual electron motion proposed by Pines (1953) is incorporated, and atomic mean excitation energies are calculated for atoms through Sr. The results are compared in a graph with those obtained theoretically by Inokuti et al. (1978, 1981) and Dehmer et al. (1975) and with the experimental values compiled by Seltzer and Berger (1982): good agreement is shown.

Wilson, J. W.↗
NASA NTRS2006

Coupled Oscillator Based Agile Beam Transmitters and Receivers: A Review of Work at JPL

This is a review of the work done at Caltech's Jet Propulsion Laboratory during the past decade on development of the coupled oscillator technology in phased array applications to spacecraft telecommunications. First, some historical background is provided to set the work in context. However, this is by no means intended to be a comprehensive review of all work in this area. Rather, the focus is on the JPL contribution with some mention of other work which provided either insight or motivation. In the mid 1990's, R. A. York, and collaborators proposed that an array of mutually injection locked electronic oscillators could provide appropriately phased signals to the radiating elements of an array antenna such that the radiated beam could be steered merely by tuning the end or perimeter oscillators of the array. York, et al. also proposed a receiving system based on such oscillator arrays in which the oscillators provide properly phased local oscillator signals to be mixed with the signals received by the array elements to remove the phase due to angle of arrival of the incident wave. These concepts were viewed as a promising simplification of the beam steering control system that could result in significant cost, mass, and prime power reduction and were therefore attractive for possible space application.

mutual injection locking↗
NASA NTRS2006

Tunable, Highly Stable Lasers for Coherent Lidar

Practical space-based coherent laser radar systems envisioned for global winds measurement must be very efficient and must contend with unique problems associated with the large platform velocities that the instruments experience in orbit. To compensate for these large platform-induced Doppler shifts in space-based applications, agile-frequency offset-locking of two single-frequency Doppler reference lasers was thoroughly investigated. Such techniques involve actively locking a frequency-agile master oscillator (MO) source to a comparatively static local oscillator (LO) laser, and effectively producing an offset between MO (the lidar slave oscillator seed source, typically) and heterodyne signal receiver LO that lowers the bandwidth of the receiver data-collection system and permits use of very high-quantum-efficiency, reasonably- low-bandwidth heterodyne photoreceiver detectors and circuits. Recent work on MO/LO offset locking has focused on increasing the offset locking range, improving the graded-InGaAs photoreceiver performance, and advancing the maturity of the offset locking electronics. A figure provides a schematic diagram of the offset-locking system.

Henderson, Sammy W.↗
NASA NTRS1996

A Derivation of the Long-Term Degradation of a Pulsed Atomic Frequency Standard from a Control-Loop Model

The phase of a frequency standard that uses periodic interrogation and control of a local oscillator (LO) is degraded by a long-term random-walk component induced by downconversion of LO noise into the loop passband. The Dick formula for the noise level of this degradation is derived from an explicit solution of an LO control-loop model.

Dick formula local oscillator frequency phase freq↗
NASA NTRS1996

A Derivation of the Dick Effect from Control-Loop Models for Periodically Interrogated Passive Frequency Standards

The phase of a frequency standard that uses periodic interrogation and control of a local oscillator (LO) is degraded by a long-term random-walk component induced by downconversion of LO noise into the loop passband. The Dick formula for the noise level of this degradation can be derived from explicit solotions of two LO control-loop models. A summary of the derivations is given here.

Dick Effect Dick Formula local oscillator noise fr↗
NASA NTRS1995

On the modeling and optimization of Schottky varactor frequency multipliers at submillimeter wavelengths

Schottky varactor frequency multipliers are used to generate local oscillator power at millimeter and submillimeter wavelengths. The equivalent circuit of the Schottky varactor contains a junction capacitance, a junction conductance, a series resistance and a model for electron velocity saturation. A millimeter wavelengths the equivalent circuits is affected by the edge effects, which are due to the small-area circular anode. The correction factors due to the edge effect for the junction capacitance and for the series resistance are available in the literature. In this work the electron velocity saturation is modeled by limiting the velocity of the transition front between the depleted and undepleted layer. By using this model the maximum current of the diode is given by the actual area of the transition front between depleted and undepleted layers, and is therefore related to the capacitance correction factor. The new model has been tested by analyzing a two diode balanced doubler for 160 GHz presented earlier in the literature. The agreement between the theoretical results and the measurements is excellent. The new diode model is useful in optimization of varactors for high millimeter and submillimeter wave frequencies.

TRT-THEORETICAL↗
NASA NTRS1980

Optical communication with two-photon coherent states. III - Quantum measurements realizable with photoemissive detectors

Homodyne detection is shown to achieve the same signal-to-noise ratio as the quantum field quadrature measurement, thus providing a receiver which realizes linear modulation TCS performance gain. The full equivalence of homodyne detection and single-quadrature field measurement is established. A heterodyne configuration which uses a TCS image-band oscillator in addition to the usual coherent state local oscillator is studied. Results are obtained by means of a representation theorem which shows that photoemissive detection realizes the photon flux density measurement.

Yuen, H. P.↗
NASA NTRS2006

Multichannel X-Band Dielectric-Resonator Oscillator

A multichannel dielectric-resonator oscillator (DRO), built as a prototype of a local oscillator for an X-band transmitter or receiver, is capable of being electrically tuned among and within 26 adjacent frequency channels, each 1.16 MHz wide, in a band ranging from 7,040 to 7,070 GHz. The tunability of this oscillator is what sets it apart from other DROs, making it possible to use mass-produced oscillator units of identical design in diverse X-band applications in which there are requirements to use different fixed frequencies or to switch among frequency channels. The oscillator (see figure) includes a custom-designed voltage-controlled-oscillator (VCO) monolithic microwave integrated circuit (MMIC), a dielectric resonator disk (puck), and two varactor-coupling circuits, all laid out on a 25-mil (0.635-mm)-thick alumina substrate having a length and width of 17.8 mm. The resonator disk has a diameter of 8.89 mm and a thickness of 4.01 mm. The oscillator is mounted in an 8.9-mm-deep cavity in a metal housing. The VCO MMIC incorporates a negative- resistance oscillator amplifier along with a buffer amplifier. The resonator disk is coupled to a microstrip transmission line connected to the negative-resistance port of the VCO MMIC. The two varactor-coupling circuits include microstrip lines, laid out orthogonally to each other, for coupling with the resonator disk. Each varactor microstrip line is DC-coupled to an external port via a microwave choke. One varactor is used for coarse tuning to select a channel; the other varactor is used (1) for fine tuning across the 1.16-MHz width of each channel and (2) as a feedback port for a phase-lock loop. The resonator disk is positioned to obtain (1) the most desirable bandwidth, (2) relatively tight coupling with the microstrip connected to the coarse-tuning varactor, and (3) relatively loose coupling with the microstrip connected to the fine-tuning varactor. Measurements of performance showed that the oscillator can be switched among any of the 26 channels and can be phase-locked to a nominal frequency in any channel. The degree of nonlinearity of tuning was found not to exceed 2.5 percent. The tuning sensitivity was found to be 6.15 MHz/V at a bias offset of -2 V on the phase-lock-loop varactor. The phase noise of the oscillator in free-running operation was found to be -107 dBc/Hz (where dBc signifies decibels relative to the carrier signal) at 100 kHz away from the carrier frequency.

Mysoor, Narayan↗
NASA NTRS1990

Submillimeter sources for radiometry using high power Indium Phosphide Gunn diode oscillators

A study aimed at developing high frequency millimeter wave and submillimeter wave local oscillator sources in the 60-600 GHz range was conducted. Sources involved both fundamental and harmonic-extraction type Indium Phosphide Gunn diode oscillators as well as varactor multipliers. In particular, a high power balanced-doubler using varactor diodes was developed for 166 GHz. It is capable of handling 100 mW input power, and typically produced 25 mW output power. A high frequency tripler operating at 500 GHz output frequency was also developed and cascaded with the balanced-doubler. A dual-diode InP Gunn diode combiner was used to pump this cascaded multiplier to produce on the order of 0.5 mW at 500 GHz. In addition, considerable development and characterization work on InP Gunn diode oscillators was carried out. Design data and operating characteristics were documented for a very wide range of oscillators. The reliability of InP devices was examined, and packaging techniques to enhance the performance were analyzed. A theoretical study of a new class of high power multipliers was conducted for future applications. The sources developed here find many commercial applications for radio astronomy and remote sensing.

Deo, Naresh C.↗