Title :
Digital Coherence Enhancement Enabling 6-GBd DP-64QAM Using a 1.4-MHz Linewidth Laser
Author :
Lavery, Domanic ; Maher, Robert ; Paskov, Milen ; Thomsen, Benn C. ; Bayvel, Polina ; Savory, Seb J.
Author_Institution :
Dept. of Electron. & Electr. Eng., Univ. Coll. London, London, UK
Abstract :
This letter demonstrates the possibility of using digital coherence enhancement-a means of estimating and digitally compensating local oscillator laser phase noise using a secondary, low speed coherent receiver-to enable the reception of high order quadrature amplitude modulation (QAM) using a monolithically integrated tunable semiconductor laser as local oscillator. We show that this coherence enhancement technique compensates both the Lorentzian and non-Lorentzian distributed phase noise of this laser, enabling reception of DP-64QAM without differential decoding, and with a record (linewidth)×(symbol duration) product of 2.3×10-4.
Keywords :
laser noise; laser tuning; light coherence; optical modulation; optical receivers; phase noise; quadrature amplitude modulation; semiconductor lasers; DP-64QAM; Lorentzian distributed phase noise; coherent receiver; digital coherence enhancement; digital compensation; frequency 1.4 MHz; high order quadrature amplitude modulation; laser phase noise; local oscillator laser; monolithically integrated tunable semiconductor laser; nonLorentzian distributed phase noise; symbol duration; Laser noise; Measurement by laser beam; Optical interferometry; Optical noise; Optical receivers; Phase noise; Coherent receivers; laser linewidth; optical communications; quadrature amplitude modulation (QAM);
Journal_Title :
Photonics Technology Letters, IEEE
DOI :
10.1109/LPT.2013.2283744
