Title :
Impact of laser linewidth on optical channel spacing requirements for multichannel FSK and ASK systems
Author :
Elrefaie, A. ; Maeda, M.W. ; Guru, R.
Author_Institution :
Bellcore, Red Bank, NJ, USA
fDate :
4/1/1989 12:00:00 AM
Abstract :
The sensitivity penalty is evaluated for amplitude-shift-keyed and frequency-shift-keyed multichannel coherent systems that use lasers with linewidths which are a significant fraction of the bit rate. The study was conducted for both ASK and FSK systems using a single-filter receiver with nonsynchronous detection. For FSK systems, both NRZ (nonreturn-to-zero) and alternate mark inversion (AMI) signal formats were studied. The optical channel spacing is strongly determined by the laser linewidth. For example, with the FSK-NRZ data rate of 150 Mb/s, the optical channel spacing which gives 1-dB crosstalk penalty is 4 GHz when the intermediate frequency linewidth is 50 MHz (laser linewidth is 25 MHz), as opposed to 1.8 GHz when the linewidth is negligible.<>
Keywords :
amplitude modulation; frequency shift keying; optical communication; optical modulation; receivers; 1 dB; 105 Mbit/s; ASK; FSK; alternate mark inversion; amplitude-shift-keyed multichannel coherent systems; bit rate; crosstalk penalty; data rate; frequency-shift-keyed multichannel coherent systems; intermediate frequency linewidth; laser linewidth; nonreturn-to-zero; nonsynchronous detection; optical channel spacing requirements; sensitivity penalty; single-filter receiver; Amplitude shift keying; Bit rate; Channel spacing; Frequency shift keying; Local oscillators; Optical crosstalk; Optical filters; Optical receivers; Optical sensors; Optical transmitters;
Journal_Title :
Photonics Technology Letters, IEEE
