Title :
Robustness to laser frequency offset in direct-detection DPSK and DQPSK systems
Author :
Kim, Hoon ; Winzer, Peter J.
Author_Institution :
Lucent Technol., Bell Labs., Holmdel, NJ, USA
Abstract :
We assess, both by measurement and simulation, the receiver performance degradation caused by frequency offsets between the optical source and the delay interferometer for nonreturn-to-zero (NRZ) and return-to-zero (RZ) differential-phase-shift-keying (DPSK) and differential-quadrature-phase-shift-keying (DQPSK) systems. We find that NRZ- and RZ-DQPSK systems are about six times more sensitive to frequency offsets than NRZ- and RZ-DPSK systems operating at the same bit rate. We explain the reason for this behavior by means of eye aperture considerations.
Keywords :
differential phase shift keying; distributed feedback lasers; light interferometers; optical fibre communication; DQPSK systems; bit rate; delay interferometers; direct-detection DPSK; eye aperture considerations; frequency offsets; laser frequency offset; performance degradation; return-to-zero differential-phase-shift-keying; Bit rate; Degradation; Delay; Differential quadrature phase shift keying; Frequency measurement; Optical interferometry; Optical receivers; Optical sensors; Optical signal processing; Robustness;
Journal_Title :
Lightwave Technology, Journal of
DOI :
10.1109/JLT.2003.816816
