To achieve a dense and efficient deployment of RRH microcells and easy initialization of their central wavelengths, tunable colorless laser transmitters are included in the ONU of the transport domain of 5G mobile radio access networks, making it easy to tune and control the radiation wavelength using various mechanisms. In the ONU, upstream wavelength control is necessary due to possible errors in setting the center wavelength during initial connection with OLT (BBU), as well as due to wavelength drift due to aging of the laser transmitter. The paper presents a new method of straight (ONU-OLT) dual-frequency wavelength initialization in one of the WDM-PON channels, built on AWG, using the process of determining the maximum amplitude modulation coefficient of the probe radiation components beating envelope as a parameter that indicates tuning to its central wavelength. Using the method makes it possible to increase the signal-to-noise ratio of the initialization channel, its sensitivity, and the accuracy of tuning to the center of the AWG channel in comparison with the known methods using the processes of direct detection of single-frequency probe radiation.
Tuning the wavelength of a colorless laser transmitter, used to build an upstream channel in the WDM-PON transport domain of a 5G mobile radio access network, to the wavelength of the maximum transmission of its multiplexer channel is implemented by a number of regulated and proactive procedures. Part I is a beginning of this article and is devoted to straight initialization. The main attention in the article will be paid to the consideration of reflective type systems. Broadband and single-frequency reflective methods for tuning direct modulation lasers: VSCEL, DFB, DBR, and external modulation lasers: integral module on InP-substrate, with direct detection and heterodyne reception are analyzed, their advantages and disadvantages are determined. The transition to modulation reflectometric methods of tuning on few close frequencies is substantiated, for which two- and three- frequency technologies for multiplexer probing based on EML lasers with scanning are proposed. The use of methods makes it possible to increase the signal-to-noise ratio, sensitivity and accuracy of multiplexer spectral characteristics measurements, and, consequently, the accuracy of tuning the wavelength of a colorless laser transmitter to the central wavelength of one of multiplexer channels.
We proposed recently a new «Smart Grids Plus» concept for digital energy grids design. These grids, in addition to layers of intelligent energy grids and information communication channels, include a layer of diagnostic monitoring based on a passive fiber optic sensor networks. Sensor networks have a hybrid TWDM structure – information exchange channels and integrated fiber optical sensors – core, based on a new technology for address interrogation and multiplexing – special addressable fiber Bragg gratings, combined for arbitrary topologies - point and quasi-distributed. Some examples of diagnostic monitoring nets for temperature control of complete switchgear contacts (point) and bus bars (quasi-distributed) are considered. Their principles of operation are discussed. The main advantages of these sensor networks are using of addressable fiber Bragg gratings simultaneously as sensors and multiplexing elements, and using of PON structure simultaneously as sensor and communication networks.
A new approach to an optical vector analyzer (OVA) realization based on double-side modulation with a suppressed carrier and formation of a reference frequency, different from it, in a fiber Bragg grating with a phase shift is considered. This realization is distinguished by an extended range and high resolution of measurements, which is shown both theoretically and experimentally.
The technology of frequency coding in channels of quantum key distribution allows to determine the ground state of photons through the value of the amplitude of its carrier, frequency modulated in phase (PM) or amplitude (AM) by a radio-frequency signal, and the resulting side components. Over the past twenty years, it has been substantially modified and improved. At the same time, in recent works, an expanded understanding of the frequency coding principle is used, in which each photon state is associated not with the phase of the modulating signal at a certain frequency, but with one or more sideband frequencies or the carrier frequency of the photon itself. In this paper, we present the results of constructing a frequency coding system of quantum key distribution (QKD) based on the serial electro-optical photon amplitude modulation and phase commutation. The possibility of reducing the probability of achieving a positive result in PNS attacks by Eva is shown by eliminating the carrier of the signal transmitted via the quantum channel from the structure of the key distribution. It was early noted, that the smallest value of QBER is achieved in schemes with a passive definition of one or two basic states of a photon, i.e. without the use of remodulation processes, that is realized in considering. Additionally it is not necessary to form a notch filter system, which is usually carried out using fiber Bragg gratings (FBG) or arrayed waveguide gratings (AWG) for discrimination the photon carrier and its sideband components.
In this paper, we consider a number of different methods that form the modern approach to the development of aircraft GTE’s noise suppression systems at service conditions. The herein-presented efficient noise suppression system on the base of fiber optic sensors makes it possible to reduce pulsations at the exhaust nozzle exit and noise levels at the engine outlet section.
KEYWORDS: Scattering, Photonics systems, Spectrum analysis, Signal to noise ratio, Modulation, Signal analyzers, Absorption, Sensors, Signal processing, Photodetectors
In this article, we present the results of research of photonic systems for spectrum analysis of the SHF-band radio signals based on "frequency-amplitude" transformation in contours of amplification or absorption of stimulated Mandelstam- Brillouin scattering (SMBS) approximation in single-mode optical fiber. Using of such systems as a means of spectrum analysis of the SHF-band radio signals allows us to eliminate many of the shortcomings of similar systems.
Design principals of universal microwave photonics system for quantum key distribution with frequency coding are concerned. Its concept is based on the possibility of creating the multi-functional units to implement the most commonly used technologies of frequency coding: amplitude, phase and combined amplitude-phase modulation and re-modulation of optical carrier. The characteristics of advanced systems based on classical approaches and prospects of their development using a combination of amplitude modulation and phase commutation are discussed. These are the valuations how to build advanced systems with frequency coding quantum key distribution, including at their symmetric and asymmetric constructions, using of the mechanisms of the photon polarization states passive detection, based on the filters for wavelength division multiplexing of modulated optical carrier side components.
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