Optics Express · 2012 · 218 citations · 13 references
EngineeringElectrical EngineeringOpticsOptoelectronicsPhotonicsLaser DiodesNoise In Semiconductor DevicesOptical Communication SystemsOptical ModulationOptical Signal ProcessingSemiconductor LasersBit Error RateBit-error Rate AnalysisError Variance EstimationNoise CharacterizationPhase NoisePhase Noise AnalysisSingle-mode LasersSingle-mode Semiconductor Lasers
The study develops a systematic method to characterize semiconductor‑laser phase noise with a low‑speed offline digital coherent receiver. The method measures field, FM‑noise, and phase‑error variance spectra with a high‑sampling‑rate receiver, then interpolates the data to 10 GS/s to predict bit‑error‑rate performance of multi‑level modulated optical signals. The measured phase‑noise characteristics accurately explain the observed BER degradation.
We develop a systematic method for characterizing semiconductor-laser phase noise, using a low-speed offline digital coherent receiver. The field spectrum, the FM-noise spectrum, and the phase-error variance measured with such a receiver can completely describe phase-noise characteristics of lasers under test. The sampling rate of the digital coherent receiver should be much higher than the phase-fluctuation speed. However, 1 GS/s is large enough for most of the single-mode semiconductor lasers. In addition to such phase-noise characterization, interpolating the taken data at 1.25 GS/s to form a data stream at 10 GS/s, we can predict the bit-error rate (BER) performance of multi-level modulated optical signals at 10 Gsymbol/s. The BER degradation due to the phase noise is well explained by the result of the phase-noise measurements.
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