Performance analysis of wavelength division multiplexing MDM-PON system using different advanced modulations

Mode division multiplexing (MDM) is very competent next generation multiplexing technique and is becoming popular among researchers these days. In this research article, an integrated passive optical network (PON) using MDM and wavelength division multiplexing (WDM) is proposed at 25 Gbps over 3 km multimode fiber (MMF) link distance. For MDM, diverse Laguerre–Gaussian (LG) such as LG12, LG15, LG18, LG111 and LG114 are incorporated and also for cost reduction, vertical cavity surface emitting laser (VCSEL) is located in optical line terminal (OLT). Performance of diverse advanced modulations such as compressed spectrum return to zero (CSRZ), duo-binary return to zero (DRZ) and modified duo-binary return to zero (MDRZ) is evaluated and compared with non-return to zero (NRZ) in terms of Bit error rate (BER) at varied MMF link lengths. Results revealed that CSRZ performance stand out and NRZ provide worst performance.

Real-Time Data Acquisition and Processing System for MHz Repetition Rate Image Sensors

An electro-optic detector is one of the diagnostic setups used in particle accelerators. It employs an electro-optic crystal to encode the longitudinal beam charge profile in the spectrum of a light pulse. The charge distribution is then reconstructed using data captured by a fast spectrometer. The measurement repetition rate should match or exceed the machine bunching frequency, which is often in the range of several MHz. A high-speed optical line detector (HOLD) is a linear camera designed for easy integration with scientific experiments. The use of modern FPGA circuits helps in the efficient collection and processing of data. The solution is based on Xilinx 7-Series FPGA circuits and implements a custom latency-optimized architecture utilizing the AXI4 family of interfaces. HOLD is one of the fastest line cameras in the world. Thanks to its hardware architecture and a powerful KALYPSO sensor from KIT, it outperforms the fastest comparable commercial devices.

Hybrid WDM free space optical system using CSRZ and Rayleigh backscattering noise mitigation

Hybrid wavelength-division-multiplexing (WDM) and free space optical (FSO) access networks are getting great attention due to numerous advantages. In this work, hybrid WDM-FSO system is demonstrated for 55 km at capacity of 5 × 10 Gbit/s using compressed spectrum return to zero (CSRZ) WDM-FSO in downstream and nonreturn to zero (NRZ) in upstream for demonstrating transmitter diversity which inturn decrease the interchannel interference. For the suppression of Rayleigh backscattering (RB) interferometric beat noise, bidirectional cyclic multiplexer is employed. Cyclic multiplexer provide λ 1 to λ 5 wavelengths for optical line terminal (OLT) to ONU transmission and λ 2 to λ 6 for ONU to OLT transmission. Insertion losses of each component are considered and in the end, power budget is also calculated. Results revealed that FSO length of 780–1050 m are obtained using various WDM-FSO downstream signals and their power budget, redundant budget, maximum distance, and insertion losses also calculated.

Management ofCommunication System in Pipeline IndustryBased on OLP Technology

In order to effectively improve the fault self-healing ability of pipeline communication system and reduce the events of communication interruption caused by fiber break or performance degradation of optical line, this paper introduces the basic principle, system composition working mode and technical requirements of OLP technology. The OLP system is firstly introduced into the relay section of long-distance pipeline to build the standby route with the spare optical fiber as material. When the in-service route is broken or the performance of optical fiber is reduced, the OLP system can automatically switch to the standby route within 50 ms to ensure the communication transmission service be uninterrupted, and even no error code alarm. Through engineering test in pipeline industry, the operability of OLP technology applied to the pipeline communication system is verified. Using the real-time monitoring data of optical cable through OLP system, we can analyze the evolution trend of optical cable line quality, precontrol in advance, and improve the level of communication management.

Implementasi Pembangunan Jaringan Mini Optical Line Termination di Kawasan Babelan milik PT Telekomunikasi Indonesia

Abstrak: Penelitian dengan judul pembangunan mini optical line termination di Kawasan Babelan, tujuan penelitian ini untuk mempelajari infrastruktur terbaru milik PT Telekomunikasi Indonesia yang mengembangkan jaringanya terus menerus untuk menjangkau wilayah yang belum mendapatkan akses internet, proses pembangunan jaringan fiber optik, PT Telekomunikasi Indonesia (Telkom) sebagai Badan Usaha Milik Negara (BUMN) yang berkonsenterasi pada bidang komunikasi, berhasil meluncurkan produk Internet Home (INDIHOME) sebagai Brand Image-nya guna memenuhi kebutuhan informasi komunikasi demi kemajuan bangsa Indonesia. Metode pengumpulan data meliputi studi lapangan dan studi pustaka. Studi lapangan meliputi praktek , wawancara dan pengamatan. Studi pustaka dilakukan dengan penilitian kepustakaan yang relevan dengan masalah yang dihadapi. Dari analisa dan pengamatan yang dilakukan bahwa jaringan akses fiber optik merupakan salah satu peningkatan yang baik guna meningkatkan efisiensi yang berpengaruh pada kecepatan mengirimkan paket data (internet). Kata kunci: Fiber Optik, Jaringan, Indihome, Optical Line Termination (OLT) Abstract: The research entitled the construction of a mini optical line termination in the Babelan area, the purpose of this research is to study the latest infrastructure owned by PT Telekomunikasi Indonesia which is developing its network continuously to reach areas that do not yet have internet access, the process of building a fiber optic network, PT Telekomunikasi Indonesia (Telkom) as The State-Owned Enterprises (BUMN), which concentrate on the communication sector, have successfully launched the Internet Home (INDIHOME) product as its Brand Image to meet the needs of communication information for the progress of the Indonesian nation. Data collection methods include field studies and literature studies. Field studies include practice, interviews and observations. Literature study is carried out with literature research that is relevant to the problem at hand. From the analysis and observations made that the fiber optic access network is one of the best improvements to improve efficiency which affects the speed of sending data packets (internet). Keywords: Fiber Optic, Network, Indihome, Optical Line Termination (OLT)

The dust mass in Cassiopeia A from infrared and optical line flux differences

ABSTRACT The large quantities of dust that have been found in a number of high-redshift galaxies have led to suggestions that core-collapse supernovae (CCSNe) are the main sources of their dust and have motivated the measurement of the dust masses formed by local CCSNe. For Cassiopeia A (Cas A), an oxygen-rich remnant of a Type IIb CCSN, a dust mass of 0.6–1.1 M⊙ has already been determined by two different methods, namely (a) from its far-infrared spectral energy distribution and (b) from analysis of the red–blue emission line asymmetries in its integrated optical spectrum. We present a third, independent, method for determining the mass of dust contained within Cas A. This compares the relative fluxes measured in similar apertures from [O iii] far-infrared and visual-region emission lines, taking into account foreground dust extinction, in order to determine internal dust optical depths, from which corresponding dust masses can be obtained. Using this method, we determine a dust mass within Cas A of at least 0.99$^{+0.10}_{-0.09}$ M⊙.

The MOSDEF survey: a comprehensive analysis of the rest-optical emission-line properties of z ∼ 2.3 star-forming galaxies

ABSTRACT We analyse the rest-optical emission-line spectra of z ∼ 2.3 star-forming galaxies in the complete MOSFIRE Deep Evolution Field (MOSDEF) survey. In investigating the origin of the well-known offset between the sequences of high-redshift and local galaxies in the [O iii]λ5008/Hβ versus [N ii]λ6585/Hα (‘[N ii] BPT’) diagram, we define two populations of z ∼ 2.3 MOSDEF galaxies. These include the high population that is offset towards higher [O iii]λ5008/Hβ and/or [N ii]λ6585/Hα with respect to the local SDSS sequence and the low population that overlaps the SDSS sequence. These two groups are also segregated within the [O iii]λ5008/Hβ versus [S ii]λλ6718,6733/Hα and the [O iii]λλ4960,5008/[O ii ]λλ3727,3730 (O32) versus ([O iii]λλ4960,5008+[O ii]λλ3727,3730)/Hβ (R23) diagrams, which suggests qualitatively that star-forming regions in the more offset galaxies are characterized by harder ionizing spectra at fixed nebular oxygen abundance. We also investigate many galaxy properties of the split sample and find that the high sample is on average smaller in size and less massive, but has higher specific star formation rate (SFR) and SFR surface density values and is slightly younger compared to the low population. From Cloudy+BPASS photoionization models, we estimate that the high population has a lower stellar metallicity (i.e. harder ionizing spectrum) but slightly higher nebular metallicity and higher ionization parameter compared to the low population. While the high population is more α-enhanced (i.e. higher α/Fe) than the low population, both samples are significantly more α-enhanced compared to local star-forming galaxies with similar rest-optical line ratios. These differences must be accounted for in all high-redshift star-forming galaxies – not only those ‘offset’ from local excitation sequences.

FIBER OPTIC INFORMATION TRANSMISSION SYSTEMS

Features of information transmission on optical fibers in the presence of spark and electric noise are investigated in detail. The purpose of research: to determine the requirements for light sources, optical cables and photodetectors most suitable for the manufacture of fiber optic systems suitable for information exchange. The object of research is fiber optic systems. Research method is theoretical. The basic requirements for the choice of light-emitting diodes, photodiodes and optical cables in the technical implementation of optical communication in the presence of spark and electromagnetic interference. KEYWORDS: LED, OPTICAL LINE, PHOTODETECTOR, INFORMATION.