Wavelength Stabilization Technique Using Dithering-Induced AM Cancellation for DWDM Systems

Yukio HORIUCHI  Shu YAMAMOTO  Masatoshi SUZUKI  

Publication
IEICE TRANSACTIONS on Communications   Vol.E84-B   No.5   pp.1145-1152
Publication Date: 2001/05/01
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Joint Special Issue on Recent Progress in Optoelectronics and Communications)
Category: Optical Systems and Technologies
Keyword: 
WDM,  wavelength stabilization,  dithering,  AWG multiplexer,  EA modulator,  

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Summary: 
We proposed and demonstrated a novel wavelength stabilization technique for dense wavelength division multiplexing (DWDM) systems using dithering-induced AM cancellation which improves both wavelength stability and data transmission performance. Our wavelength stabilization technique consists of an optical frequency discriminating function and a function for canceling AM components induced by frequency dithering of the light source. The frequency discrimination in this technique is based on an FM-AM conversion effect, obtained by interaction from frequency dithering of the light with the bandpass characteristic of an arrayed-waveguide grating (AWG) multiplexer. The AM cancellation function was added to suppress optical frequency discriminating errors occurring due to AM components induced by frequency dithering in this wavelength stabilization architecture. In this scheme, an electro-absorption (EA) modulator is employed not only for modulating high-speed data traffic but also for suppressing AM components induced by frequency dithering on the light signal. Since the EA modulator is usually used for modulating high-speed data traffic, dedicated optical devices are not required for suppressing the AM components. The wavelength stability of a light source can therefore be enhanced with simple architecture. In the demonstration, a reduction of fluctuations within 50 MHz versus changes in the modulation index, and long-term stability within 320 MHz after more than 60 hours was achieved in 10 Gbit/s NRZ transmission. We also confirmed that the proposed AM cancellation technique effectively reduces the transmission penalties due to frequency dithering in 10 Gbit/s NRZ data transmission performance.