Title :
Passive equalization of semiconductor diode laser frequency modulation
Author :
Alexander, S.B. ; Welford, D. ; Marquis, D. VL
Author_Institution :
MIT Lincoln Lab., Lexington, MA, USA
Abstract :
Optical heterodyne communication systems using direct-frequency-modulated (FM) semiconductor diode lasers often exhibit system degradation because of the nonuniform injection-current-to-FM transfer function present in most semiconductor diode lasers. In a FSK system, a nonuniform FM transfer function causes tone drift which results in increased crosstalk between time slots and a corresponding degradation in system bit-error rate (BER). Using simple passive electrical networks it is possible to equalize the nonuniform FM response and substantially reduce this transfer-function-induced BER degradation. The theory, computer optimation, construction, and test of various equalization networks and their use in realizing an FM-equalized transmitter for a 100-Mb/s binary FSK communication system is described.<>
Keywords :
frequency modulation; frequency shift keying; optical communication equipment; optical modulation; semiconductor junction lasers; 100 Mbit/s; FSK system; computer optimation; construction; crosstalk; nonuniform frequency modulation response; optical heterodyne communication systems; passive electrical networks; passive equalisation; semiconductor diode laser frequency modulation; system degradation; tone drift; Bit error rate; Communication systems; Degradation; Frequency shift keying; Optical crosstalk; Optical mixing; Optical transmitters; Semiconductor diodes; Semiconductor lasers; Transfer functions;
Journal_Title :
Lightwave Technology, Journal of
