We propose and demonstrate using photonic integrated circuit (PIC) technology, a tunable-laser based FBG interrogator suitable for low noise seismic applications sampling at kHz rates and delivering <120dB re(nm2/Hz) noise floor over a 500Hz bandwidth.

0U 2.0 micron wavelength injection seed semiconductor laser for lidar transmitter for global-scale measurements of CO2 [11180-29] 0V Stable and high power 515-nm lasers for the space gravitational wave detector: DECIGO [11180-30] 0W Correlated atom accelerometers for mapping the Earth gravity field from Space [11180-31] OPTICAL COMMUNICATION PROGRAMS AND MISSIONS 2 0X Global quasi-real-time-services back to Europe: EDRS Global [11180-32] 0Y The CubeSat Laser Infrared CrosslinK Mission (CLICK) [11180-33] 0Z Optical intersatellite links for navigation constellations [11180-34] 10 1550-nm combined transmission booster amplifier and

Fugro is a worldwide operating Geotechnical, Survey and asset monitoring company headquartered in The Netherlands. Over 50 years we have pioneered the geotechnical industry with groundbreaking technical inventions, starting from the cone penetrometer which led to the start of Fugro (“Foundationand Ground Mechanics”). In the current presentation we will introduce a Fugro developed fiberoptic measurement system, based on the use of discrete Fiber Bragg Gratings and some aspects of its performance, as well as a case study of the application of this system with over 700 sensors using a single fiberoptic interrogator system.

Optical sensors based on Fiber Bragg Gratings (FBGs) are used in several applications and industries. In order for fiber optic sensors to compete with electrical sensors, several critical parameters of both the sensors and sensor interrogators need to be in place such as performance, cost, size, reliability relevant to the target application. Here we have developed a tunable laser based optical interrogator which delivers high performance (up to 8kHz sweep-rate and 120dB dynamic range) and precision (< 100fm) by optimizing the laser calibration of a telecom tunable laser and incorporating optical periodic wavelength references (e.g. MZI) to correct and compensate for wavelength non-linearity and noise during operation. Scaling up optical sensing systems to deliver high level of performance over a large number of sensors is enabled by synchronizing multiple interrogators. Further improvements can be achieved by using photonic integrated circuit (PIC) technology which reduces the footprint, cost, and improves performance. There exists several PIC technology platforms (e.g. InP, Si, TriPlex) that could be used to develop different optical building blocks used in the interrogator. Such building blocks include the tunable laser, couplers, photodiodes, MZIs, etc. are available on the InP platform. Here we have demonstrated the operation of an interrogator using PIC technology to replace many of the discrete optical components. The design and chip manufacturing was carried out as part of an InP multi-project wafer (MPW) run under the EU PARADIGM project. A custom package supporting fiber arrays was designed and manufactured to demonstrate the PIC functionality in an optical interrogator.

Fiber Bragg Gratings (FBGs) are increasingly being employed in a novel range of applications, especially in sensing and measurement field. Some of these novel FBG-based sensing applications, especially those requiring high resolution sensing in harsh environments, impose challenges on Bragg gratings and their performance. Additionally, there is a growing list of Fiber Bragg Grating types and manufacturing techniques, each with its own strengths and disadvantages. With the new generation of fiber optic interrogation technologies reaching femtometer-level resolution in Bragg wavelength tracking, the achievable accuracy and stability of the sensing system is becoming limited by the performance of the employed Bragg grating itself. In many cases, correct selection and definition of the FBG parameters can result in defining the success of the sensing system. Here, we explore the specifications of Bragg gratings that are most relevant to FBG-based sensors, propose their characterization and analysis methodologies and explore their effects for both static and dynamic sensing applications in combination with tunable laser based fiber optic interrogation techniques. Bragg gratings manufactured by several different techniques are compared to demonstrate their suitability for different types of sensing applications. Several application focused examples are also provided to demonstrate the importance of the parameters for detection of strain, pressure, sound, vibration and tilt using fiber optic sensors.

Fiber Bragg Gratings (FBGs) allow for optical detection of localized physical effects without the need to couple the light out and back into a fiber, enabling robust and multiplexed sensor systems. The need of combining wide bandwidth and high resolution for dynamic sensing applications, like acoustics and vibrations, has presented significant challenges for FBG-based solutions. Here, we present a novel FBG-based measurement system enabled by using high-speed and high-precision tunable laser-based optical interrogation scheme. Multiple levels of integrated wavelength referencing coupled with low-noise high-speed electronics allow for spectral feature tracking at a resolution of <20 fm at kHz-frequencies. In combination with fiber accelerometers that employ unique force transmission mechanisms, amplifying strain on the Bragg grating and increasing the resonance frequency of the transducer, resolutions <10 mu g (150 Hz bandwidth) to submg resolution in kHz-frequencies is achieved. Similarly, compact wavelength-multiplexed hydrophones with wide range linearity and dynamic range, sub-Pa resolution and flat-sensitivity down to static pressures are demonstrated. The sensors are demonstrated to be customizable to application-specific requirements, and designed to be scalable to large quantity reproducible manufacturing.In contrast to interferometry-based solutions, the tunable swept-laser detection scheme in combination with strain-based FBG sensors provides a cost-effective system that allows for easy scaling of sensor counts per fiber with multiple fibers being simultaneously recorded. Finally, the integrated high accuracy triggering and hybrid measurement capabilities present the potential to monitor sounds and vibrations in a wide range of applications from seismic surveys to machine and structural monitoring applications in harsh environments.

Fugro is a worldwide oil and gas service operator with the core business of data acquisition offshore, onshore and in the air. In a world with increasingly complex and costly systems being installed, often in remote, harsh or difficult to access environments, large scale continuous monitoring of these valuable and critical assets is becoming an increasingly important challenge. These monitoring systems need to collect wide variety of data: strain, sound, vibrations, pressure, temperature etc. FAZ Technology as part of the Fugro group has developed an ultra-high performance data acquisition system based on fiber optics, perfectly suited for acquiring large amounts of system and structural health and status data. We will present the concept, its performance and capabilities, and we’ll present real field applications. A core example will be a system installed on the Fugro offshore survey vessel Pioneer, which monitors a large suite of performance and health data of this vessel allowing online diagnostics as well as prediction of upcoming failure events. The system allows many sensors on a single light weight optical fiber, long distance recording and is robust and stable in a harsh offshore environment. Its functionality is well-suited for various offshore and onshore O&G industry installations, including subsea systems. We will discuss the functional details of the system, its performance, field data, and give an outlook on further developments.

Determining the operational performance and health of large-scale assets often require the continuous monitoring of a wide range of parameters, from strain, temperature and pressure to vibration and sound. In many situations, it is highly desirable from cost and system robustness point of view to have a centralized data acquisition and analytics for the entire asset. For such applications, fiber optics becomes an ideal option, owing to its inherent characteristics: long distance and lossless data transmission, ability to multiplex and chain multiple sensors, cheaper cabling and passive (electricity-free) sensors. Here, we present a portfolio of fiber optic sensors, based on Fiber Bragg Grating (FBG) technology, which includes strain, temperature and pressure gauges as well as accelerometers and acoustic detectors. Using novel techniques to leverage the inherent strain and temperature sensitivity of FBGs, for example, drift-free high resolution temperature compensated pressure gauges have been designed and demonstrated. In another example, accelerometers that operate with constant sensitivities from static (0 Hz) to dynamic (kHz) frequency range provide ability to record both tilt and vibration from single sensors, wellsuited for machine and structure monitoring.

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In order for fiber optic sensors to compete with electrical sensors, several critical parameters need to be addressed such as performance, cost, size, reliability, etc. Relying on technologies developed in different industrial sectors helps to achieve this goal in a more efficient and cost effective way. FAZ Technology has developed a tunable laser based optical interrogator based on technologies developed in the telecommunication sector and optical transducer/sensors based on components sourced from the automotive market. Combining Fiber Bragg Grating (FBG) sensing technology with the above, high speed, high precision, reliable quasi distributed optical sensing systems for temperature, pressure, acoustics, acceleration, etc. has been developed. Careful design needs to be considered to filter out any sources of measurement drifts/errors due to different effects e.g. polarization and birefringence, coating imperfections, sensor packaging etc. Also to achieve high speed and high performance optical sensing systems, combining and synchronizing multiple optical interrogators similar to what has been used with computer/processors to deliver super computing power is an attractive solution. This path can be achieved by using photonic integrated circuit (PIC) technology which opens the doors to scaling up and delivering powerful optical sensing systems in an efficient and cost effective way.

Optical sensors based on Fiber Bragg Gratings (FBGs) are used in several applications and industries. Several inscription techniques and type of fibers can be used. However, depending on the writing process, type of fiber used and the packaging of the sensor a Polarization Dependent Frequency Shift (PDFS) can often be observed with polarized tunable laser based optical interrogators. Here we study the PDFS of the FBG peak for the different FBG types. A PDFS of <1pm up to >20pm was observed across the FBGs. To mitigate and reduce this effect we propose a polarization mitigation technique which relies on a synchronous polarization switch to reduce the effect typically by a factor greater than 4. In other scenarios the sensor itself is designed to be birefringent (Bi-FBG) to allow pressure and/or simultaneous temperature and strain measurements. Using the same polarization switch we demonstrate how we can interrogate the Bi-FBGs with high accuracy to enable high performance of such sensors to be achievable.

This paper reports on the optimization of the design of piezoelectric transducer elements integrated on doubly-clamped microbeam resonators utilized as (bio) chemical sensors. We report and emphasize the often forgotten influence of membrane stresses on defining the dimensions and optimal position of the piezoelectric transducer elements. The study takes into account stress induced structural changes and provides models for the equivalent motional parameters of resonators with particular shapes of the transducers matching the flexural modes of vibration. The above is analyzed theoretically using numerical models and is confirmed by impedance measurements and optical measurements of fabricated doubly-clamped beam resonators. We propose various transducer designs and highlight the advantages of using higher order vibration modes by implementing specially designed mode matching transducer elements. It is concluded that the paper describes and highlights the importance of accounting for the membrane stresses to optimize the resonator performance and the low power in electronic feedback of resonating sensing systems.

Western societies all see their healthcare costs outpace GDP growth. To reverse this trend, several public and private initiatives were taken in the last years to make healthcare more cost efficient. It is anticipated that micro and nano-system technology will help enable an increase in the functionality of lifestyle and healthcare devices to gradually reduce cost. This builds on the scaling of microelectronics that additionally provides opportunities for reducing both form factor and power requirements. In the next decade, body area network technology will be one of the advancements that provides medical, lifestyle, assisted living, sports or entertainment functions for the user. Such a network comprising a series of miniature sensor nodes, implanted or located around the body should be able to communicate with other sensor nodes and/or with a gateway node that provides a connection to the outside world using a standard telecommunication infrastructure. Early deployment of technology in different application cases are translated into critical technology obstacles that need to be solved in order to enable wide-spread deployment. For the development of smaller and smarter systems with ever increasing autonomy, key technological challenges are addressed at the level of sensors, energy harvesting, ultra-low-power DSP, wireless connectivity, and integration and packaging.[GRAPHICS]Healthcare expenditure increase of a few selected countries (OECD data (OECD Health Data, http://www.oecd.org, accessed Jan. 10, 2013) showing a dramatic increase compared to the GDP. (C) 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper presents a novel readout circuit for micro-mechanical resonant sensors. To determine the sensor's resonance frequency and quality factor, the sensor is briefly excited, after which the exponentially-decaying ring-down current produced by a piezoelectric transducer is read out by an auto-zeroed trans-impedance amplifier (TIA). An auto-zeroed comparator then detects zero- and level-crossings for frequency counting and quality factor measurement. A new circuit topology is proposed to reduce errors due to leakage currents. Moreover, a reconfigurable TIA enhances the circuit's flexibility. A prototype chip has been implemented in a 0.35 μm CMOS process. Experimental results obtained using a silicon-nitride clamped-clamped beam resonator are in good agreement with results obtained using conventional impedance analysis. In a measurement time of 2 ms, the circuit achieves a 50 ppm detection limit in resonance frequency, 5 times better than prior work, while consuming only 31.5 μA from a 3.3 V supply.

This paper presents an energy-efficient readout circuit for resonant sensors that operates based on a transient measurement method. The resonant sensor is driven at a frequency close to its resonance frequency by an excitation source that can be intermittently disconnected, causing the sensor to oscillate at its resonance frequency with exponentially decaying amplitude. By counting the zero crossings of this ring-down response, the interface circuit can detect the resonance frequency. In contrast with oscillator-based readout, the presented readout circuit is readily able to detect quality factor (Q) of the resonator from the envelope of the ring-down response, and can be used even in the presence of large parasitic capacitors. A prototype of the readout circuit has been integrated in 0.35 μm CMOS technology, and consumes only 36 μA from a 3.3 V supply during a measurement time of 2 ms. The resonance frequency and quality factor of a micro-machined SiN resonator obtained using this prototype are in good agreement with results obtained using impedance analysis. Furthermore, a clear transient response is observed to ethanol flow using the presented readout, demonstrating the use of this technique in sensing applications.

In this paper, we demonstrate the implementation of a real-time volatile detection system using an electronic readout interfacing a functionalized piezoelectric micromechanical resonator for frequency shift tracking. The readout circuit is based on a trans-impedance sustaining amplifier and it is assembled from off-the-shelf components. The 2.08 MHz oscillator system achieves a measured Allan deviation of 3 Hz at 10 ms integration time. Exposure to varying concentrations of ethanol in a controlled dry nitrogen flow yielded a normalized sensitivity of -7.48 x 10(-6) ppm(-1). These results pave the way toward compact and portable measurement systems capable of ppm-level detection resolution for low-molecular weight volatile compounds. (C) 2012 Elsevier B.V. All rights reserved.

We study the dynamics of a nonlinear electromechanical oscillator with delayed feedback. Compared to their linear counterparts, we find that the dynamics is dramatically different. The well-known Barkhausen stability criterion ceases to exist, and two modes of operation emerge: one characterized by hysteresis in combination with a bistable frequency and amplitude; the other, by self-stabilization of the oscillation frequency and amplitude. The observed features are captured by a model based on a Duffing equation with delayed force feedback. Nonlinear oscillators with delayed force feedback are exemplary for a large class of dynamic systems.

An electronic nose based on an array of vibrating doubly clamped beams is proposed. These very high aspect ratio (length/thickness) suspended resonators can be individually functionalized by applying polymer coatings with an inkjet printing approach. The absorption of volatile compounds induces a swelling of the polymers that result in axial stress formation and a shift of the resonance frequency. Furthermore, integrated piezoelectric transducers are used for both actuating the resonators, as well as monitoring their resonance frequency in an oscillator loop. This allows for detection at ppm-level concentrations of low molecular weight volatiles. More importantly, the generic resonant transducers can be individually coated with different polymers to allow for selective detection of volatile compounds. Here, we present the first results demonstrating the obtained selectivity by varying the coating chemistry on identical resonators.