Semiconductor laser of high reliability for single-mode fiber-optic communication links

Introduction: This article is based on the recent research work in the field of two subjects: signal data parameters in fiber optic communication links, and dispersive properties of optical signals caused by non-homogeneous material phenomena and multimode propagation of optical signals in such kinds of wired links.Purpose: Studying multimode dispersion by analyzing the propagation of guiding optical waves along a fiber optic cable with various refractive index profiles of the inner optical cable (core) relative to the outer cladding, as well as dispersion properties of a fiber optic cable due to inhomogeneous nature of the cladding along the cable, for two types of signal code sequences transmitted via the cable: return-to-zero and non-return-to-zero ones.Methods: Dispersion properties of multimode propagation inside a fiber optic cable are analyzed with an advanced 3D model of optical wave propagation in a given guiding structure. The effects of multimodal dispersion and material dispersion causing the optical signal delay spread along the cable were investigated analytically and numerically.Results: Time dispersion properties were obtained and graphically illustrated for two kinds of fiber optic structures with different refractive index profiles. The dispersion was caused by multimode (e.g. multi-ray) propagation and by the inhomogeneous nature of the material along the cable. Their effect on the capacity and spectral efficiency of a data signal stream passing through such a guiding optical structure is illustrated for arbitrary refractive indices of the inner (core) and outer (cladding) elements of the optical cable. A new methodology is introduced for finding and evaluating the effects of time dispersion of optical signals propagating in fiber optic structures of various kinds. An algorithm is proposed for estimating the spectral efficiency loss measured in bits per second per Hertz per each kilometer along the cable, for arbitrary presentation of the code signals in the data stream, non-return-to zero or return-to-zero ones. All practical tests are illustrated by MATLAB utility.

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The Engagement of Hybrid Ultra High Space Division Multiplexing with Maximum Time Division Multiplexing Techniques for High-Speed Single-Mode Fiber Cable Systems

Journal of Optical Communications ◽

10.1515/joc-2019-0205 ◽

2019 ◽

Vol 0 (0) ◽

Author(s):

I. S. Amiri ◽

P. G. Kuppusamy ◽

Ahmed Nabih Zaki Rashed ◽

P. Jayarajan ◽

M. R. Thiyagupriyadharsan ◽

...

Keyword(s):

Communication Systems ◽

High Speed ◽

Single Mode ◽

Single Mode Fiber ◽

Design Parameters ◽

Control Parameters ◽

Data Rates ◽

Fiber Optic Communication ◽

High Space ◽

Optic Communication

AbstractHigh-speed single-mode fiber-optic communication systems have been presented based on various hybrid multiplexing schemes. Refractive index step and silica-doped germanium percentage parameters are also preserved during their technological boundaries of attention. It is noticed that the connect design parameters suffer more nonlinearity with the number of connects. Two different propagation techniques have been used to investigate the transmitted data rates as a criterion to enhance system performance. The first technique is soliton propagation, where the control parameters lead to equilibrium between the pulse spreading due to dispersion and the pulse shrinking because of nonlinearity. The second technique is the MTDM technique where the parameters are adjusted to lead to minimum dispersion. Two cases are investigated: no dispersion cancellation and dispersion cancellation. The investigations are conducted over an enormous range of the set of control parameters. Thermal effects are considered through three basic quantities, namely the transmission data rates, the dispersion characteristics, and the spectral losses.

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A Unified Method for Design and Analysis of Analog/Digital Fiber Optic Communication Links

Journal of Optical Communications ◽

10.1515/joc.1994.15.3.104 ◽

1994 ◽

Vol 15 (3) ◽

Author(s):

A. Peled ◽

J. Zohar ◽

J. Gavan

Keyword(s):

Fiber Optic ◽

Communication Links ◽

Fiber Optic Communication ◽

Optic Communication ◽

Unified Method

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Failure Analysis of Fiber Optic Communication System in Deep-Water Remotely Operated Vehicle ROSUB 6000

Marine Technology Society Journal ◽

10.4031/mtsj.48.3.11 ◽

2014 ◽

Vol 48 (3) ◽

pp. 63-72 ◽

Cited By ~ 1

Author(s):

Raju Ramesh ◽

Dharmaraj Sathianarayanan ◽

Vittal Doss Prakash ◽

Arumugam Vadivelan ◽

Sethuraman Ramesh ◽

...

Keyword(s):

Low Temperature ◽

Failure Analysis ◽

Deep Water ◽

Fiber Optic ◽

Single Mode ◽

Single Mode Fiber ◽

Link Failure ◽

Remotely Operated Vehicle ◽

Link Loss ◽

Optic Communication

AbstractSingle-mode fiber optic systems can play vital roles in cabled deep-water vehicle operations at greater depths (>3,000 m). One kind of single-mode fiber optic system, the ROSUB 6000, is used in a deep-water work-class remotely operated vehicle (ROV). Fiber optic link failure of ROV telemetry and sound navigation and ranging were noticed at a water depth of 3,050 m during the ROSUB 6000 system sea trials. A failure analysis of the fiber optic communication system was carried out with the link data logged during different phases of the deep-sea trials. The results from the failure analysis carried out during deep-sea trials showed an increase in the fiber optic link loss from a depth of 900 m onwards. Further analysis of the fiber optic link loss in the laboratory involved pressure and low-temperature testing of all the subsea components in the ROV telemetry link. From the laboratory pressure test results, it was concluded that pressure was not the root cause of the fiber optic link failure. On further analysis, a complete fiber optic link failure was noticed during the low-temperature testing of the subsea components. Furthermore, the low-temperature testing of the individual subsea components revealed that the fiber optic rotary joint (FORJ) insertion loss increased rapidly at low temperatures. This FORJ insertion loss led to complete failure of the fiber optic links in the ROV. The degradation of index-matching fluid in the FORJ was identified to be the root cause of fiber link failure.

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