scholarly journals A Directly Modulated Laterally Coupled Distributed Feedback Laser Array Based on SiO2 Planarization Process

2020 ◽  
Vol 11 (1) ◽  
pp. 221
Author(s):  
Qichao Wang ◽  
Jian Wang ◽  
Changzheng Sun ◽  
Bing Xiong ◽  
Yi Luo ◽  
...  
Keyword(s):  
Semiconductor Lasers ◽  
Communication Networks ◽  
High Speed ◽  
Low Cost ◽  
Single Mode ◽  
Distributed Feedback ◽  
Laser Array ◽  
Fiber Communication ◽  
Dfb Laser ◽  
Planarization Process

Low-cost and high-speed single-mode semiconductor lasers are increasingly required as wide-band access fiber communication expands in recent years. Here, a high-speed laterally coupled distributed feedback (LC-DFB) laser array is achieved based on a SiO2 planarization process. The device exhibits low threshold currents of about 12 mA and high slope efficiencies over 0.26 W/A. Stable single mode operation and high-speed performance are realized with side mode suppression ratios (SMSR) over 45 dB, and 3-dBe bandwidths exceed 14 GHz for all four channels. Such a high-speed and process simple LC-DFB laser array shows great potential to the low-cost fiber communication networks.

scholarly journals Towards a Glass New World: The Role of Ion-Exchange in Modern Technology

2021 ◽  
Vol 11 (10) ◽  
pp. 4610
Author(s):  
Simone Berneschi ◽  
Giancarlo C. Righini ◽  
Stefano Pelli
Keyword(s):  
Ion Exchange ◽  
Communication Networks ◽  
High Speed ◽  
High Performance ◽  
Low Cost ◽  
Modern Technology ◽  
Historical Background ◽  
Wide Range ◽  
Happy Marriage

Glasses, in their different forms and compositions, have special properties that are not found in other materials. The combination of transparency and hardness at room temperature, combined with a suitable mechanical strength and excellent chemical durability, makes this material indispensable for many applications in different technological fields (as, for instance, the optical fibres which constitute the physical carrier for high-speed communication networks as well as the transducer for a wide range of high-performance sensors). For its part, ion-exchange from molten salts is a well-established, low-cost technology capable of modifying the chemical-physical properties of glass. The synergy between ion-exchange and glass has always been a happy marriage, from its ancient historical background for the realisation of wonderful artefacts, to the discovery of novel and fascinating solutions for modern technology (e.g., integrated optics). Getting inspiration from some hot topics related to the application context of this technique, the goal of this critical review is to show how ion-exchange in glass, far from being an obsolete process, can still have an important impact in everyday life, both at a merely commercial level as well as at that of frontier research.

DFB Lasers with Tilted Waveguide for Multi-Wavelength Generation

2007 ◽  
Vol 31 ◽  
pp. 36-38 ◽  
Author(s):  
Lip Fah Chong ◽  
Jing Hua Teng ◽  
Ee Leong Lim ◽  
Norman Soo Seng Ang ◽  
J.R. Dong ◽  
...  
Keyword(s):  
Single Mode ◽  
Distributed Feedback ◽  
Couple Mode ◽  
Threshold Condition ◽  
Couple Mode Theory ◽  
Gain Margin ◽  
Ridge Waveguides ◽  
Multi Wavelength ◽  
Dfb Laser ◽  
Lasing Frequency

In this paper, we present the theoretical investigation of index-coupled distributed feedback (DFB) laser with tilted single mode ridge waveguides. By tilting part of the ridge waveguide in various degrees, DFB laser with manifold effective grating periods can be realized. The structure is analyzed using couple mode theory in matrix form based on threshold analysis. Important parameters of DFB laser like resonant frequency and threshold gains are obtained by solving the eigen-equation. The results indicate not only that the lasing frequency is modulated by the waveguide titling angle, but also large Gain Margin (GM) can be achieved at the threshold condition which enhance the stable single mode operation in index-coupled DFB laser.

Analysis of the stability of multiple-phase-shift distributed-feedback semiconductor lasers

1993 ◽  
Vol 71 (1-2) ◽  
pp. 29-38 ◽  
Author(s):  
Yves Champagne ◽  
Nathalie McCarthy
Keyword(s):  
Phase Shift ◽  
Semiconductor Lasers ◽  
Output Power ◽  
Longitudinal Mode ◽  
Single Mode ◽  
Distributed Feedback ◽  
Hole Burning ◽  
Lasing Wavelength ◽  
Multiple Phase ◽  
The Stability

The effects of the longitudinal spatial hole burning on the static lasing characteristics of a specific configuration of distributed-feedback semiconductor laser with three phase-shift regions are investigated using a numerical approach. A serious degradation of the stability of the optimum design, having the flattest axial intensity distribution at low output power, is predicted for drive levels beyond a critical value. The lasing wavelength exhibits a sudden shift (wavelength chirping), along with a significant degradation of the single-mode character of the longitudinal-mode spectrum. Thus, the potentialities of this multiple-phase-shift structure to provide a stable narrow-linewidth emission at high output power appear to be less than expected from results calculated for the near-threshold regime. Nevertheless, it is found that a multiple-phase-shift configuration that departs slightly from the optimum case suffices to recover most of the promises expected from this distributed-feedback laser design.

MULTIWAVELENGTH LIGHT SOURCE WITH INTEGRATED DFB LASER ARRAY AND STAR COUPLER FOR WDM LIGHTWAVE COMMUNICATIONS

1994 ◽  
Vol 05 (01) ◽  
pp. 91-109 ◽  
Author(s):  
C.E. ZAH ◽  
J. GAMELIN ◽  
B. PATHAK ◽  
F. FAVIRE ◽  
P.S.D. LIN ◽  
...  
Keyword(s):  
Low Cost ◽  
Single Mode ◽  
Cost Effective ◽  
Single Mode Fiber ◽  
Laser Source ◽  
Photonic Integration ◽  
Laser Array ◽  
Laser Arrays ◽  
Wavelength Division ◽  
Multiwavelength Laser

We discuss the advantages of wavelength-division-multiplexed (WDM) lightwave systems and the need for monolithically integrated multiwavelength laser arrays. For WDM light-wave systems to be cost effective, it is important to reduce the per-wavelength component cost. By photonic integration, the packaging and the control circuitry will be shared among all the wavelengths. In this paper, we review the multiwavelength laser arrays, the array coupling, and the photonic integration approach. We have demonstrated the monolithic integration of a 21-wavelength multi-quantum-well distributed-feedback laser array with a star coupler and optical amplifiers on the same chip. Operating a packaged module under CW operation, we obtained as many as 15 individual wavelengths simultaneously launched from one output port of the star coupler of this integrated chip into one lensed single-mode fiber. We also characterized the thermal and the electrical crosstalk from the neighboring lasers. This integrated chip stands a good chance of being a compact and low-cost multiwavelength laser source for future WDM lightwave systems.

An ultra-dense spacing-based PON by incorporating dual drive Mach–Zehnder modulator for comb generation

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Navjot Singh ◽  
Bharat Naresh Bansal
Keyword(s):  
Optical Networks ◽  
High Speed ◽  
Low Cost ◽  
Optical Network ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Passive Optical Network ◽  
Passive Optical Networks ◽  
Differential Phase Shift ◽  
High Data

Abstract Wavelength division multiplexed passive optical is promising technique to achieve a high data rate and large number of user. The notable advantages of WDM PON is the combination of reliability, cheap in cost, accessible bandwidth, high security, large optical reach and it can support large number of ONU. There are multiple approaches to achieve high-speed WDN PON using different transmission techniques. In WDM, multiple lasers are required which increase the cost of the system. To reduce cost, an optical multicarrier generation system is proposed. An economical multiple carrier generation with the incorporation of sine generator and Mach–Zehndar modulator is demonstrated. Utmost work of sine generator and dual drive modulator was to attain low cost functioning of passive optical networks. Multicarrier generation was done and replacement of laser carriers with optical multicarrier generator. Carriers were generated with the frequency spacing of 20 GHz and these carriers were used in the passive optical networks with the tone-to-noise ratio of 40 dB, amplitude difference of 1.4 dB. For the transmission of downstream in the PON, differential phase shift keying was employed at 10 Gbps data speed. Transmission distance achieved was 30 km using single-mode fiber and this was a part of optical distribution network. Optical network unit was next part after ODN and signals were received with balanced receiver. Moreover, half signal was given to intensity modulator for the signal re-modulation. Bit error rate of 10–9 was achieved at all channels in the downstream. An upstream of 10 Gbps was accomplished in the passive optical network.

scholarly journals The Role of Transport Communications in Ensuring Political and Economic Security: the Unlearned Lessons of History

2021 ◽  
Vol 22 (1) ◽  
pp. 142--162
Author(s):  
Alexandr Shalak
Keyword(s):  
Communication Networks ◽  
High Speed ◽  
Low Cost ◽  
Far East ◽  
Economic Security ◽  
Soviet Period ◽  
Social Infrastructure ◽  
Historical Experience ◽  
Small Aircraft

The article focuses on historical experience and the importance of transport communications in controlling the economic space and ensuring security of the state. The historical-and-geopolitical approach was used as the methodological framework of the present research. The purpose of the text is to illustrate with milestone historical examples the role of transport communications in binding the Russian space as well as in securing its mobility. The conducted analysis resulted in several meaningful conclusions. The stretched-out communications and low population density undermine the competitive opportunities of the Russian state. The modern strategy of railway development should be aimed at construction of high-speed rail networks, which would enable economic development and promote innovative technologies. The significance of water communications is attributed to their low cost and the world biggest length of rivers and maritime boundaries. The growth of small aircraft fleet, which practically ceased to exist in the post-Soviet period, should become the strategic priority in air communications development. Small aircraft is able to ensure the labor force mobility and provide the access to social infrastructure in sparcely populated areas of European Russia, Siberia and the Far East. The article emphasizes the sharp decline in rate of highways construction, particularly the ones of regional level. The main reasons for slow progress in construction of transport communications in the modern time are lack of political will as well as absence of sound strategy for their development. Based on comparative analysis and historical experience, the article stresses the role and importance of strategic planning and government investment for development of transport communication networks.

scholarly journals Furtherance in Splicing Technique of Optical Fiber Communication

2020 ◽  
Vol 9 (3) ◽  
pp. 3505-3609
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
High Speed ◽  
Single Mode ◽  
Optical Fiber Communication ◽  
Communication Line ◽  
Long Distance ◽  
Fiber Communication ◽  
Splice Loss ◽  
Distance Communication

The improvement in technology over long distance communication using optical fiber has been regulated over past few decades, and it took drastic enhancement in one of the major parameter for joining two OFC cable (splicing). The different experiments performed in order to bring about the result that can give nearly 0dB splice loss when there is shifting of entire set up of Optical Fiber Communication. The splicing loss is created by the joining of two SMF using fiber optic fusion splicing. The objective of this paper is to determine the low splice loss in joining two single mode or multimode optical fiber, such that long distance communication that required multiple infrastructure assembly for its operational unit can be made relocatable as there is large investment and material and electronic circuitry is associated to it. Therefore to reduce that cost we have sets of analysis that splicing loss can be reduced to 0dB for SMFSMF end face connection or at least no improvement in splice losses while relocation of OFC infrastructure from one place to other place as the result of the tested experiment. Based on experiment conducted we came to conclusion that with essential requirements for establishing a low-loss and high-speed communication line using optical fibers, the need for quality of splicing technology along with perfect core alignment angle is required to reduce splice loss, such that the infrastructure can be shifted to many different location without any additional cost of new material and new resources. The exact measurement of splice loss can be insured by another set of formula which we came across during the experimental performance.

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