• P-ISSN 0974-6846 E-ISSN 0974-5645

Indian Journal of Science and Technology

Article

Indian Journal of Science and Technology

Year: 2022, Volume: 15, Issue: 25, Pages: 1224-1233

Original Article

Effect of High Frequency Gain on the Performance of Optical Costas Loop in Face of Loop Delay

Received Date:10 September 2021, Accepted Date:21 September 2021, Published Date:09 July 2022

Abstract

Objectives: Optical costas loops (OCLs) are widely used in optical communication as homodyne receivers. Due to use of different electronic counterparts and fibre optic cable inherent loop delay always presents in the system. The steady state behaviours of optical costas loop are highly affected by the presence of loop delay. Different nonlinear behaviours may be observed due to presence of delay. There are two main objectives of this article. Firstly, how OCL can be operated as stable receiver up to some large value of loop delay by using a proportional plus integrating type loop filter (LF). Secondly, how a controlled chaotic optical signal can be generated from OCL by choosing the system parameters in correct manner. Methods: To investigate system behaviours of OCL both analytical and numerical methods have been used. Stability analysis of OCL has been done by Routh-Hurwitz method. From stability analysis, it is possible to predict the stable and unstable behaviour of the OCL in presence of delay and how system stability can be improved by high frequency gain value of LF. Numerical methods have also been used to solve the nonlinear equation of OCL to observe real time behaviours. Findings: Analytical findings show that loop stability can be improved by increasing the value of high frequency gain of LF. For large value of loop delay, chaotic oscillation of phase error may be observed in OCL. The chaotic oscillation can also be controlled by high frequency gain with certain extent value of loop delay. All the numerical findings have been properly verified with numerical results. Novelty: This article describes how effects of loop delay can be controlled to run OCL in steady as well as in unsteady state. From designer’s point of view this study would be helpful to choose correct values of system parameters to improve the performance of OCL in optical communication. It also gives the idea for generation of chaotic optical signal, which is used in secured communications.

Keywords: Optical Costas loop; Optical Phase locked loop Phase detector; Loop filter; Nonlinear dynamics; and optical communications

References

  1. Gardner F. McPhees lock Techniques. (2nd Edition). New York. John Wiley. 1979.
  2. Herzog F, Kudielka K, Erni D, Bachtold W. Optical Phase Locking by Local Oscillator Phase Dithering. IEEE Journal of Quantum Electronics. 2006;42(10):973–985. Available from: https://doi.org/10.1109/JQE.2006.881413
  3. Banerjee A, Biswas B. Stability Analysis of a PSK modified homodyne optical receiver. International Journal of Electronics and Communication Engineering. 2012;3(1):32–40. Available from: https://iaeme.com/MasterAdmin/Journal_uploads/IJECET/VOLUME_3_ISSUE_2/IJECET_03_02_004.pdf
  4. Sarkar BC, H. Performance degradation of an optical Costas loop due to non-ideal response of 90 degree hybrid. Indian Journal of Pure & Applied Physics. 1999;37:66–72. Available from: http://nopr.niscair.res.in/handle/123456789/26980
  5. Paillier L, Bidan RL, Conan JM, Artaud G, Vedrenne N, Jaouen Y. Space-Ground Coherent Optical Links: Ground Receiver Performance With Adaptive Optics and Digital Phase-Locked Loop. Journal of Lightwave Technology. 2020;38(20):5716–5727. Available from: https://doi.org/10.1109/JLT.2020.3003561
  6. Xuan Z, Aflatouni F. Integrated coherent optical receiver with feed-forward carrier recovery. Opt Express. 2020;28:16073–16088. Available from: https://doi.org/10.1364/OE.389865
  7. Chen X, Liu X, Shan Y, Zhang Y, Hu Q, Li J, et al. Z-domain model procedure for heterodyne digital optical phase-locked loop. Optik. 2021;241:167173.
  8. Chen X, Liu X, Zhang Y, Shan Y, Hu Q, Li J, et al. Z-domain modeling methodology for homodyne digital optical phase-locked loop. IEICE Electronics Express. 2021;18(10):20210078.
  9. Sakamoto T, Chiba A, Kanno A, Morohashi I, Kawanishi T. Real-time homodyne reception of 40-Gb/s BPSK signal by digital optical phase-locked loop. 36th European Conference and Exhibition on Optical Communication. 2010;p. 1–3. Available from: https://doi.org/10.1109/ECOC.2010.5621234
  10. Endo T, Chua LO. Bifurcation diagrams and fractal brain boundaries of phase-locked loop circuits. IEEE Transactions on Circuits and Systems. 1990;37(4):534–540. Available from: https://doi.org/10.1109/31.52756
  11. Sarkar BC, De B, Sarkar S. Structure and performance of a new data clock time recovery phase locked loop. Indian Journal of Engineering and Materials Sciences. 1996;3(5):185–190. Available from: http://nopr.niscair.res.in/handle/123456789/29804
  12. Diaz R, Chan SC, Liu JMM. Lidar detection using a dual-frequency source. Optics Letters. 2006;31(24):3600. Available from: https://www.osapublishing.org/ol/abstract.cfm?uri=ol-31-24-3600
  13. Sarkar BC, Chakraborty S. Self-oscillations of a third order PLL in periodic and chaotic mode and its tracking in a slave PLL. Communications in Nonlinear Science and Numerical Simulation. 2014;19(3):738–749. Available from: https://doi.org/10.1016/j.cnsns.2013.07.003
  14. Hilborn RC, Sprott JC. Chaos and Nonlinear Dynamics: An Introduction for Scientists and Engineers. American Journal of Physics. 1994;62(9):861–862.
  15. Dandapathak M, Sarkar S, Sarkar BC. Nonlinear dynamics of an optical phase locked loop in presence of additional loop time delay. Optik. 2014;125(23):7007–7012. Available from: https://doi.org/10.1016/j.ijleo.2015.09.133

Copyright

© 2022 Dandapathak. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Published By Indian Society for Education and Environment (iSee)

DON'T MISS OUT!

Subscribe now for latest articles and news.