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We report on the design, fabrication and electro-optical characterization at T = 2.9 K of a photon number resolving detector designed to obtain a pulse-position resolution. This pulse-position-resolving detector (PPRD) is based on the spatial multiplexing of four superconducting nanowire avalanche photodiodes (SNAPs) [8, 9] connected in series. We choose to exploit the 2-SNAP configuration (i.e.,...
In the framework of the EU-funded research project “FABULOUS” we experimentally demonstrate an innovative FDMA-PON architecture whose upstream transmission is based on a reflective Mach-Zehnder modulator, reaching an overall upstream capacity of 32 Gbps per wavelength over 31 dB ODN loss in several previously published experiments targeting 1 Gbps per user and using 16-QAM as a modulation format....
We have experimentally investigated the RF linewidth and timing jitter in self-mode-locked two-section quantum dash lasers emitting at ∼1.55 µm and operating at ∼21 GHz repetition rate, subjected to single and dual loop optical feedback into the gain section, over a wide range of feedback delay. Various feedback conditions are investigated and optimum levels determined for narrowest linewidth and...
A novel radio over fiber (RoF) and free space optics (FSO) hybrid system based on optical OFDM (OOFDM) signal transmission is proposed in this paper to provide high capacity optical wireless indoor communication links. A low cost transmission scheme based on IM-DD is proposed to simplify and reuse existing infrastructure to deploy a high bandwidth FSO link. This paper shows the experimental results...
Low coherence interferometry (LCI) is a well-known measurement technique able to provide an axial precision in the order of the microns. Its application to a wide variety of fields like medicine has attracted the interest of many authors mainly due to its non-invasive characteristic. By combining LCI and microwave photonics (MWP), we take profit from the inherent stability that the RF domain offers...
Dispersion has very strong detrimental effects on high data rate incoherent transmission systems. Situation gets much worse when data bits become only a few picoseconds long. In this paper we investigate how the dispersion can affect an optical auto-correlation function in optical code division multiple access (OCDMA) systems when data are carried by two-dimensional wavelength-hopping time-spreading...
In this paper we demonstrate a low-complexity pre-emphasis technique for electronic subcarrier-multiplexed signals to mitigate transceiver bandwidth limitations. As opposed to traditional FFT/FIR-based pre-emphasis techniques, we propose a simple and effective power-ratio optimization between electronic subcarriers that requires only 1 real multiplication per subcarrier.
We demonstrate a symmetric dual loop feedback scheme, insensitive to delay phase tuning, for a self-mode-locked quantum dash laser emitting at ∼ 1.55 µm and operating at ∼ 21 GHz repetition rate. These lasers are subjected to single and dual loop optical feedback into the gain section. Various feedback conditions are studied and optimum levels determined for narrowest linewidth and reduced timing...
In this paper we present real-time transmission performances up to 25 Gbit/s for optical access network. Our solution is based at transceiver side on pre-coded NRZ and electrical duo-binary modulations using limited electrical bandwidth DML in C and O band. At the receiver side, an electrical duo-binary receiver based on an 8 GHz APD photodiode combined with an online duo-binary to binary converter...
In this paper, we present our custom design atmospheric channel emulator for free space optical (FSO) system evaluations in a controlled environment. Our emulator is in the form of an atmospheric chamber with dimensions of 60 cm × 40 cm × 300 cm. It is equipped with adjustable heaters, coolers and fans to create the turbulence. It also houses a fog generator and droplet watering system to generate...
Related to different international activities in the Optical Wireless Communications (OWC) field Graz University of Technology (TUG) has high experience on developing different high data rate transmission systems and is well known for measurements and analysis of the OWC-channel. In this paper, a novel approach for testing Free Space Optical (FSO) systems in a controlled laboratory condition is proposed...
WDM has been generally proposed to groom wavelengths for transport applications. This paper will describe our attempt to reduce cost and energy consumption of smart network elements, through an extended use of WDM techniques at the data link level. This paper will draw the advantages of this approach and will demonstrate that this new direction is efficient to keep the frequency processing at a reasonable...
We report on the design and experimental characterization of a novel pair of underwater wireless optical modems. Each of them is equipped with a blue LED array as transmitter, an APD photodiode as receiver and a pin photodiode for optical power monitoring. The modems are designed to operate at 10 Mbit/s (10BaseT Ethernet, Manchester-coded signal) in harsh conditions, i.e. in turbid water and with...
We demonstrate a bidirectional real-time symmetric 1.25 Gbit/s per user UDWDM-PON with simple DSP-less transceivers. ODN losses of 38 dB are achieved in a 12.5 GHz grid which includes both downstream and upstream with HD video transmission.
We report experimentally and theoretically a new state in which injection locking of the parallel polarization and simultaneous excitation of the orthogonal polarization in a single-transverse mode VCSEL are obtained. We find very simple analytical expressions for the power of both linear polarizations. A simple nonlinear dependence between the power of both linear polarizations and the frequency...
The power transfer function of a nonlinear optical loop mirror (NOLM) is experimentally investigated for both continuous-wave and pulsed operation of the pump signal. The difference between transmission and reflection responses is discussed in view of using the interferometer for the amplitude regeneration of multilevel signals.
We demonstrate an error-free transmission of 10-Gbit/s optical signals along a SiGe waveguide at a wavelength of 1.98 µm. Bit error rate measurements confirm the absence of penalty during the transmission through a 2.5-cm long waveguide having a width of 2.2 µm.
We report measurement of mode-locking process using optical pulse ruler. It can provide an approachable optical pulse measurement tool like a litmus paper for pH measurement in a liquid solution.
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