Mr. Philipp Putzer Profile

Philipp Putzer

at OHB System AG

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Publications (10)

Proceedings Article | 20 November 2017 Open Access

Design of a fiber-optic interrogator module for telecommunication satellites

Philipp Putzer, Alexander Koch, Markus Plattner, Andreas Hurni, Markus Manhart

Proceedings Volume 10564, 105641F (2017) https://doi.org/10.1117/12.2309040

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Proceedings Article | 17 November 2017 Open Access

Selection of fiber-optical components for temperature measurement for satellite applications

P. Putzer, N. Kuhenuri Chami, A. Koch, A. Hurni, M. Roner, J. Obermaier, N. M. Lemke

Proceedings Volume 10563, 105631C (2017) https://doi.org/10.1117/12.2304276

KEYWORDS: Sensors, Fiber Bragg gratings, Temperature metrology, Transducers, Aluminum, Satellites, Optical fibers, Fiber optics sensors, Fiber optics, Astronomical imaging

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The Hybrid Sensor Bus (HSB) is a modular system for housekeeping measurements for space applications. The focus here is the fiber-optical module and the used fiber-Bragg gratings (FBGs) for temperature measurements at up to 100 measuring points. The fiber-optial module uses a tunable diode laser to scan through the wavelength spectrum and a passive optical network for reading back the reflections from the FBG sensors. The sensors are based on FBGs which show a temperature dependent shift in wavelength, allowing a high accuracy of measurement.

The temperature at each sensor is derivated from the sensors Bragg wavelength shift by evaluating the measured spectrum with an FBG peak detection algorithm and by computing the corresponding temperature difference with regard to the calibration value. It is crucial to eliminate unwanted influence on the measurement accuracy through FBG wavelength shifts caused by other reasons than the temperature change. The paper presents gamma radiation test results up to 25 Mrad for standard UV-written FBGs in a bare fiber and in a mechanically housed version. This high total ionizing dose (TID) load comes from a possible location of the fiber outside the satellite's housing, like e.g. on the panels or directly embedded into the satellites structure. Due to the high shift in wavelength of the standard written gratings also the femto-second infrared (fs- IR) writing technique is investigated in more detail.

Special focus is given to the deployed fibers for the external sensor network. These fibers have to be mechanically robust and the radiation induced attenuation must be low in order not to influence the system's performance. For this reason different fiber types have been considered and tested to high dose gamma radiation. Dedicated tests proved the absence of enhanced low dose rate sensitivity (ELDRS). Once the fiber has been finally selected, the fs-IR grating will be written to these fibers and the FBGs will be tested in order to investigate the radiation induced wavelength shift.

The FBGs react on temperature and strain change, so a decoupling of both physical effects must be assured to allow a precise measurement over large temperature ranges and corresponding potential mechanical stress, passed from the structure to the sensor. This potential source of error is addressed with the design of a strain-decoupled temperature transducer to which the FBGs are glued. The design of the transducer and measurement results of a bending test are provided within this paper.

An outlook of the usage of fiber-optical sensing in space applications will be given. One promising field of application are the so called photonically-wired spacecraft panels, where optical fibers with integrated FBGs are being integrated in panels for temperature measurements and high-speed data transfer at the same time.

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Proceedings Article | 17 November 2017 Open Access

Fiber optical sensing on-board communication satellites

A. Hurni, N. M. K. Lemke, M. Roner, J. Obermaier, P. Putzer, N. Kuhenuri Chami

Proceedings Volume 10563, 105631B (2017) https://doi.org/10.1117/12.2304166

KEYWORDS: Sensors, Fiber optics sensors, Fiber optics, Fiber Bragg gratings, Satellites, Analog electronics, Fiber optic communications, Multiplexers, Temperature metrology, Semiconductor lasers

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Striving constantly to reduce mass, AIT effort and overall cost of the classical point-to-point wired temperature sensor harness on-board telecommunication satellites, OHB System (formerly Kayser-Threde) has introduced the Hybrid Sensor Bus (HSB) system. As a future spacecraft platform element, HSB relies on electrical remote sensor units as well as fiber-optical sensors, both of which can serially be connected in a bus architecture. HSB is a modular measurement system with many applications, also thanks to the opportunities posed by the digital I²C bus. The emphasis, however, is on the introduction of fiber optics and especially fiber-Bragg grating (FBG) temperature sensors as disruptive innovation for the company’s satellite platforms.

The light weight FBG sensors are directly inscribed in mechanically robust and radiation tolerant fibers, reducing the need for optical fiber connectors and splices to a minimum. Wherever an FBG sensor shall be used, the fiber is glued together with a corresponding temperature transducer to the satellites structure or to a subsystem. The transducer is necessary to provide decoupling of mechanical stress, but simultaneously ensure a high thermal conductivity.

HSB has been developed in the frame of an ESA-ARTES program with European and German co-funding and will be verified as flight demonstrator on-board the German Heinrich Hertz satellite (H2Sat). In this paper the Engineering Model development of HSB is presented and a Fiber-optical Sensor Multiplexer for a more flexible sensor bus architecture is introduced. The HSB system aims at telecommunication satellite platforms with an operational life time beyond 15 years in geostationary orbit. It claims a high compatibility in terms of performance and interfaces with existing platforms while it was designed with future applications with increased radiation exposure already in mind.

In its basic configuration HSB consists of four modules which are the Power Supply Unit, the HSB Controller Module, the Interrogator Controller Module and the Analog Front-End for the fiber-optical interrogation. The Interrogator Controller Module handles both, the electrical and fiber-optical sensor network. For the latter it is to be completed by the Analog Front-End. On this front-end, a tunable laser diode is implemented for the scanning of the FBG sensors. The reflected spectra are measured on multiple fiber channels and are then evaluated by use of a peak detection algorithm in order to obtain a precise temperature measurement. The precise operation of the photonic system on long terms can be guaranteed thanks to an inorbit calibration concept.

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Proceedings Article | 25 September 2017 Open Access

Design challenges of a tunable laser interrogator for geo-stationary communication satellites

Selwan Ibrahim, Arthur Honniball, Raymond McCue, Michael Todd, John O’Dowd, David Sheils, Liberis Voudouris, Martin Farnan, Andreas Hurni, Philipp Putzer, Norbert Lemke, Markus Roner

Proceedings Volume 10562, 105620Y (2017) https://doi.org/10.1117/12.2296150

KEYWORDS: Sensors, Fiber Bragg gratings, Fabry–Perot interferometers, Temperature metrology, Tunable lasers, Polarization, Absorption, Fiber optics sensors, Satellites, Radiation effects

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Recently optical sensing solutions based on fiber Bragg grating (FBG) technology have been proposed for temperature monitoring in telecommunication satellite platforms with an operational life time beyond 15 years in geo-stationary orbit. Developing radiation hardened optical interrogators designed to be used with FBG sensors inscribed in radiation tolerant fibers offer the capabilities of multiplexing multiple sensors on the same fiber and reducing the overall weight by removing the copper wiring harnesses associated with electrical sensors.

Here we propose the use of a tunable laser based optical interrogator that uses a semiconductor MG-Y type laser that has no moving parts and sweeps across the C-band wavelength range providing optical power to FBG sensors and optical wavelength references such as athermal Etalons and Gas Cells to guarantee stable operation of the interrogator over its targeted life time in radiation exposed environments. The MG-Y laser was calibrated so it remains in a stable operation mode which ensures that no mode hops occur due to aging of the laser, and/or thermal or radiation effects.

The key optical components including tunable laser, references and FBGs were tested for radiation tolerances by emulating the conditions on a geo-stationary satellite including a Total Ionizing Dose (TID) radiation level of up to 100 krad for interrogator components and 25 Mrad for FBGs.

Different tunable laser control, and signal processing algorithms have been designed and developed to fit within specific available radiation hardened FPGAs to guarantee operation of a single interrogator module providing at least 1 sample per second measurement capability across <20 sensors connected to two separate optical channels.

In order to achieve the required temperature specifications of ±0.5°C across a temperature range of -20°C to +65°C using femtosecond inscribed FBGs (fs-FBG), a polarization switch is used to mitigate for the polarization dependent frequency shift (PDFS) induced from fs-FBG which could be in the order of < 20 pm causing < 2°C error in the measurement. Also special transducers were designed to isolate the strain from the FBGs to reduce any strain influence on the FBG temperature measurements while ensuring high thermal conductivity.

In this paper we demonstrate the operation of an optical FBG interrogator as part of a hybrid sensor bus (HSB) engineering model system developed in the frame of an ESA-ARTES program and is planned to be deployed as a flight demonstrator on-board the German Heinrich Hertz geo-stationary satellite.

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Proceedings Article | 25 September 2017 Open Access

Fiber based optical frequency comb: technical challenge for space applications

Philipp Putzer, Sebastian Schweyer, Norbert Lemke

Proceedings Volume 10562, 1056246 (2017) https://doi.org/10.1117/12.2296201

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Proceedings Article | 25 September 2017 Open Access

Photonically wired spacecraft panels: an economic analysis and demonstrator for telecommunication satellites

Philipp Putzer, Andreas Hurni, Bent Ziegler, Aikaterini Panopoulou, Norbert Lemke, Ivo Costa, Celeste Pereira

Proceedings Volume 10562, 1056211 (2017) https://doi.org/10.1117/12.2296194

KEYWORDS: Fiber Bragg gratings, Sensors, Fiber optics, Satellites, Connectors, Transducers, Optical fibers, Telecommunications, Fiber optics sensors, Astronomical imaging

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In this paper we present the design of smart satellite panels with integrated optical fibers for sensing and data communication. The project starts with a detailed analysis of the system needs and ends with a demonstrator breadboard showing the full performance during and after environmental tests such as vibrations and temperature.

Future science missions will need higher bandwidth in the Gbit/s range for intra-satellite communications, so the step from electrical transmission media towards fiber-optical media is the logical next step to cope with future requirements. In addition, the fibers can be used to monitor temperatures directly underneath satellite payloads which will reduce the integration effort in a later phase. For temperature monitoring so called fiber Bragg gratings (FBGs) are written in special radiation tolerant fibers, which reflection wavelength allows a direct link to temperature at the grating position. A read-out system for FBGs to use within satellite applications is currently under development at OHB.

For this study, first the environmental requirements for the panels are derived and in a second stage the functional requirements are defined. To define the functional requirements a telecommunication satellite platform, in the case here the Small-GEO series from OHB, has been taken as baseline. Based on the configuration of temperature sensors, communication lines and electrical signaling a possible replacement by fiber-optical technology was defined and traded w.r.t. its economic benefit.

It has been pointed out that the replacement of temperature sensors will reduce harness mass, but the great benefit is seen here in the reduction of assembly effort. Once the satellite panel is manufactured, the temperature sensors are already implemented at certain positions. Another point for mass savings which has pointed out is the replacement of the high-voltage or high- current high power commands (HPC) by fiber optics. Replacing some of the several hundred of required HPC lines with very light-weight fibers would reduce the HPC harness by some tens of kilograms. A detailed table illustrating the mass savings and also the integration time savings will be presented in the paper.

To keep the track on an economic solution also a detailed market research was carried out to find suitable components for fiber-optical connectors, fibers and protections buffers. Specially for the connectors a solution based on military qualified connectors pointed out to be the most interesting solution in terms of price and functionality, especially when using multi-pole connectors.

The project closes with the construction of a breadboard demonstrator consisting of three different panels, one large panel (ca. 1 m²) and two smaller panels (ca. 0.3 m²). The large panel and one of the small panels are made out of aluminum facesheets whereas the other small panels is made out of CFRP.

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Proceedings Article | 18 June 2014 Paper

Concept and design of an FBG emulator for a scanning laser-based fiber optic interrogator

Nader Kuhenuri, Philipp Putzer, Alexander Koch, Johannes Obermaier, Sebastian Schweyer, Andreas Hurni

Proceedings Volume 9098, 90980D (2014) https://doi.org/10.1117/12.2049949

KEYWORDS: Fiber Bragg gratings, Sensors, Signal attenuation, Polarization, Calibration, Fiber optics sensors, Fiber optics, Actuators, Photodiodes, Microelectromechanical systems

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Proceedings Article | 13 May 2013 Paper

A space-borne fiber-optic interrogator module based on narrow-band tunable laser diode for temperature monitoring in telecommunication satellites

P. Putzer, N. Kuhenuri, A. Koch, S. Schweyer, A. Hurni, M. Plattner

Proceedings Volume 8788, 878810 (2013) https://doi.org/10.1117/12.2020495

KEYWORDS: Fiber Bragg gratings, Sensors, Signal to noise ratio, Field programmable gate arrays, Fiber optics, Fiber optics sensors, Computer simulations, Temperature metrology, Convolution, Error analysis

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Proceedings Article | 6 April 2012 Paper

Concept and design of a fiber-optic and an I2C hybrid sensor bus system for telecommunication satellites

P. Putzer, A. Hurni, M. Manhart, C. Tiefenbeck, M. Plattner, A. Koch

Proceedings Volume 8345, 83453L (2012) https://doi.org/10.1117/12.914787

KEYWORDS: Sensors, Fiber Bragg gratings, Satellites, Fiber optics sensors, Telecommunications, Fiber optics, Optical fibers, Tunable lasers, Field programmable gate arrays, Interfaces

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Proceedings Article | 27 May 2011 Paper

High temperature sensing with FBGs using a tunable laser interrogation system

B. Eder, M. Plattner, P. Putzer, P. Eckert, A. Reutlinger, T. Zeh

Proceedings Volume 8082, 80823M (2011) https://doi.org/10.1117/12.889650

KEYWORDS: Fiber Bragg gratings, Sensors, Temperature metrology, Semiconductor lasers, Combustion, Optical fibers, Tunable lasers, Reflectors, Laser systems engineering, Stereolithography

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