Title :
5 Gbit/s direct optical DPSK modulation of a 1530-nm DFB laser
Author_Institution :
Bellcore, Red Bank, NJ, USA
Abstract :
5 Gb/s direct optical differential-phase-shift-keying (DPSK) modulation of a 1530-nm distributed feedback (DFB) laser is demonstrated using injection current modulation with a bipolar signal format. Delay demodulation is performed using an interferometer with a delay time T equal to the duration of one bit. The input and differentially encoded nonreturn to zero (NRZ) signals are shown. The bipolar modulation current signal is basically the time derivative of the NRZ signal. There was no degradation of the optical DPSK signal due to thermal frequency modulation of the laser. The direct DPSK modulation technique avoids the insertion loss and systems complexity of external DPSK modulators.<>
Keywords :
distributed feedback lasers; optical communication equipment; optical modulation; phase shift keying; semiconductor junction lasers; 1530 nm; 5 Gbit/s; NRZ signal; bipolar modulation current signal; bipolar signal format; delay time; direct optical differential phase shift keying modulation; distributed feedback laser; injection current modulation; interferometer; thermal frequency modulation; time derivative; Delay effects; Demodulation; Differential quadrature phase shift keying; Distributed feedback devices; Laser feedback; Optical feedback; Optical interferometry; Optical modulation; Optical signal processing; Thermal degradation;
Journal_Title :
Photonics Technology Letters, IEEE
