Fiber-reflection-induced impairments in lightwave AM-VSB CATV systems

Author

Darcie, Thomas E. ; Bodeep, George E. ; Saleh, Adel A M

Author_Institution

AT&T Bell Lab., Holmdel, NJ, USA

Volume

9

Issue

8

fYear

1991

fDate

8/1/1991 12:00:00 AM

Firstpage

991

Lastpage

995

Abstract

Impairments due to multiple fiber reflections are evaluated for amplitude-modulated (AM) vestigial-side-band (VSB) lightwave cable TV (CATV) systems using directly modulated distributed feedback (DFB) lasers or externally modulated diode-pumped YAG laser transmitters. For DFB lasers, the spectral broadening caused by laser chirp results in a Gaussian optical spectrum with a width near 5 GHz. Square-law detection of multipath signals from two -30-dB reflections results in an effective intensity noise near -150 dB/Hz. For externally modulated YAG lasers, the same multiple reflections result in interference that cannot be described by an effective RIN. Although the total interference power is comparable to that of the DFB lasers, the signal and interference are highly correlated. As a result of this correlation, multipath interference for YAG-based systems cannot be measured using the standard test procedure with unmodulated carriers

Keywords

amplitude modulation; cable television; light reflection; optical links; optical modulation; Gaussian optical spectrum; cable TV; directly modulated DFB lasers; externally modulated diode-pumped YAG laser transmitters; intensity noise; interference power; laser chirp; lightwave AM-VSB CATV systems; multipath interference; multipath signals; multiple fiber reflections; spectral broadening; square law detection; vestigial-side-band; Amplitude modulation; Chirp modulation; Distributed feedback devices; Fiber lasers; Interference; Laser feedback; Laser noise; Optical fiber cables; Optical reflection; Optical transmitters;

fLanguage

English

Journal_Title

Lightwave Technology, Journal of

Publisher

ieee

ISSN

0733-8724

Type

jour

DOI

10.1109/50.84165

Filename

84165