The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
We verify by system analysis that in a multi subcarrier radio over fiber system, the error vector magnitude (EVM) as a function of the subcarrier input power (Pin) is independent of the channel selection if our new channel allocation scheme is used.
FTTH networks based on Open Access have been very common in Finland and especially Sweden in the past 10 – 15 years. In such networks, an operator-neutral network provider (NP) offers competing service providers access to the end users under non-discriminatory conditions. Among the advertised benefits of open FTTH networks is the development of an open market for high-quality digital societal services,...
This paper reports the experimental results of the co-transmission of a multi-band LTE-A and gigabit/s baseband 4-PAM signals over 35 m and over 50 m of 1 mm core diameter PMMA GI-POF, using low-cost components. Both links used a red light 650nm laser diode and p-i-n photodiode with transimpedance amplifier. The 4-PAM transmission achieved 1.2 Gb/s (BER<1×10−3) for both the 35 m and the 50 m links,...
We study experimentally the pulsed emission of a passively mode-locked multi-section quantum-well semiconductor laser emitting picosecond short optical pulses at a fundamental repetition rate of 20 GHz and at a wavelength of 1070 nm. We identify different regions of picosecond short pulses dependent on the laser biasing conditions and relate them to the investigated mode-locking stability by means...
Array waveguide gratings (AWGs) are a key component in WDM systems, allowing for de-multiplexing and routing of wavelength channels. A high-resolution AWG able to satisfy challenging requirements in terms of insertion loss and X-talk is what is needed to contribute to the paradigm change in the deployment of optical communication that is nowadays occurring within the ROADM architectures. In order...
Potential photonic imaging and time-critical applications based on passively mode-locked semiconductor lasers require a precise knowledge of instabilities of these ultra-short pulse sources. These instabilities mainly manifest in a decreased timing jitter and amplitude jitter of the generated optical pulse train. Their origins are a net gain window outside the optical pulse or an imbalance of gain...
The paper illustrates the design of two pumping schemes for Mid-IR lasers based on photonic crystal fibers (PCFs) made of dysprosium doped chalcogenide glass Dy3+:Ga5Ge20Sb10S65. The simulation is performed by taking into account the spectroscopic parameters measured on the rare earth-doped glass sample in order to perform a realistic feasibility investigation. The first pump scheme provides an optical...
Application of various types of diffractive optical elements (DOE) for the generation of cylindrical vector beams on the basis of uniaxial crystals is analyzed. DOEs operating in the first order of diffraction make it possible to generate structured laser beams with inhomogeneous polarization but their energetic efficiency is low. A spiral phase plate is characterized by high efficiency but it does...
Elastic light scattering from a germanium microsphere with a radius of 2000 µm is analyzed numerically in the terahertz region from 297 µm to 303 µm. Germanium has a high refractive index (n = 4) in the terahertz range [1], which makes it possible to trap light effectively and achieve high quality factor whispering gallery modes (WGMs) [2]. Microsphere WGMs have high quality factors [3,4] and germanium...
This paper presents a comprehensive numerical study on the surface relief technique implemented in nitride Vertical-Cavity Surface-Emitting Laser (VCSEL) emitting in the 414-nm range. We calculated the threshold currents and optical modes in VCSEL structures with and without a surface relief. A standard structure was based on the first continuous-wave nitride VCSEL reported to operate at room temperature...
Transparent glass-ceramic materials containing PbWO4 crystalline phase were fabricated during heat treatment of lead borate glasses singly doped with Dy3+ and Er3+ ions. Luminescence spectra of lanthanide ions in precursor glasses and glass-ceramics were examined under different excitation wavelengths. Strengthening and broadening blue bandwidth linked with 4F9/2 → 6H15/2 transition of Dy3+ were observed...
We experimentally verified the resilience of the semiconductor optical amplifier with holding beam injection to reflections from transmission line in bidirectional operation over 200 km single fiber path together with influence of the temperature. The experiments show possible positive effects of such configurations with potential to improve bit error rate of transmitted signals.
The effect of increasing temperature on the optical, spectroscopic and structural properties of phospho-silicate nano-composites thin films SPNCTF and monolith SPNCM were studied. Doping the mentioned prepared forms of sample with some rare earth oxide such as Neodymium (Nd3+), Erbium (Er3+), Holmium (Ho3+) etc… SPNCRETF and SPNCREM have been prepared. Such materials could be promising for wave guide...
In this paper, continuous tuning of four-wave mixing bands in an ethanol-filled photonic crystal fiber is investigated. A wide tuning range of the parametric bands, from 745 nm to 920 nm (signal) and from 1260 nm to 1710 nm (idler), is achieved through the thermo-optic effect. This corresponds to a frequency tuning range higher than 2000 cm−1; such wide range can be particularly useful in applications...
We present the design of 8-channel, 100 GHz Si3N4 based AWGs applying our proprietary AWG-Parameters tool. This tool was already used in various silica based AWG designs and also technologically verified. The designed AWGs were simulated by two commercial photonics tools and the achieved transmission characteristics were evaluated. The AWGs were designed for TM-polarized light with a central wavelength...
SiO2-P2O5-HfO2-Al2O3-Na2O planar waveguide was fabricated by rf-sputtering technique. The optical, structural and morphological parameters were measured by various techniques such as m-line spectroscopy, Energy Dispersive X-ray Spectroscopy and Atomic Force Microscopy. The waveguide exhibits a single propagation mode at 1319 and 1542 nm with an attenuation coefficient of 0.2 dB/cm in the infrared...
In this paper, we present an extension of the modified single oscillator model able to predict the temperature related variations of refractive index of InP/InGaAsP materials. Model is based on three parameters- oscillation energy, dispersion energy and bandgap energy. The proposed model enables to calculate the thermo-optic coefficient in the typical telecommunication wavelength range. The obtained...
In this paper we present a multi-flow transmitter developed within the EU project PANTHER and we evaluate its first proof-of-concept demonstration of up to two single- or dual-polarization optical flows with selectable wavelength, m-QAM modulation format, number of carriers and destination. Multiflow operation is realized by two polymer boards allowing optical carrier management and optional polarization...
The next generation of optical networks requires the development of optical technology that supports high bandwidth, such as the coherent systems. The coherent detection allows the in-phase and quadrature components of a QPSK signal to be extracted as a result of the interference with a local oscillator. An integrated optics flexible 90° hybrid coupler device based on a single organic-inorganic di-ureasil...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.