Effects of intermodulation distortion on the performance of a hybrid radio/fiber system employing a self-pulsating laser diode transmitter

A self-pulsating laser is used to generate a multicarrier (five radio frequency (RF) channels) microwave optical signal for use in a hybrid radio/fiber system. The self-pulsation is achieved by external light injection into the laser diode. By varying the RF channel spacing, we have been able to estimate the degradation in system performance due to intermodulation distortion (caused by the nonlinear dynamic response of the laser). The power penalty on the central RF channel is found to be 3.2 dB for operation at the RF band around the laser self-pulsation frequency of 18.5 GHz. We have also characterized the performance of the multicarrier hybrid radio/fiber system in the frequency band corresponding to the inherent relaxation frequency of the laser

Optical pulse generation at frequencies up to 20 GHz using external-injection seeding of a gain-switched commercial Fabry-Pérot laser

We demonstrate that by using strong external-injection seeding of gain-switched Fabry-Perot (FP) lasers, it is possible to generate optical pulses at repetition rates far in excess of the laser bandwidth. Experimental results illustrate the generation of optical pulses at frequencies up to 20 GHz from a FP laser with a 3-dB bandwidth of only 8 GHz. The optical pulses generated have a duration around 12 ps, and a spectral width of 40 GHz

Multifunctional operation of a fiber Bragg grating in a WDM/SCM radio over fiber distribution system

A radio over fiber distribution system incorporating both sub-carrier multiplexing (SCM) and wavelength division multiplexing (WDM) technologies is presented. The SCM signal contains five 155-Mbit/s data channels, centered around 18.5 GHz with 450 MHz spacing. This signal is directly modulated onto three high-speed lasers with emission frequencies spaced by 50 GHz. Bragg filters are employed at the receiver base-station in order to both demultiplex the required optical channel and ensure that the detected signal is single sideband (in order to overcome dispersion limitations on the link). Our results show negligible degradation in system performance for the demultiplexing of the WDM signal compared with the back-to-back performance curves

Multiple RF carrier distribution in a hybrid radio/fiber system employing a self-pulsating laser diode transmitter

A self-pulsating laser diode is used to generate a multicarrier microwave optical signal for use in a hybrid radio/fiber system. The self-pulsation frequency of the laser is controlled by external light injection, and can be varied between 14-24 GHz. The hybrid radio/fiber system, employing the self-pulsation laser, is used to distribute two 155-Mb/s data signals on two radio frequency (RF) carriers (at 18.5 and 18.9 GHz). Experimental results show the overall system performance for both RF channels, and demonstrate that the performance is improved by around 17 dB compared with the case when the laser is used without external injection, and thus, does not self-pulsat

Continuous repetition rate tuning with timing window independent self-seeding of a gain-switched Fabry-PÉrot Laser

In this work, we propose a novel self-seeding technique that yields timing window independent operation allowing continuous repetition rate tuning of the self-seeded gain-switched (SSGS) laser. This is achieved by employing a highly linearly chirped fiber Bragg grating (LC FBG) as a wavelength selective element. The reflected gain-switched pulses are dispersed to such an extent, that temporal overlap occurs between them. This overlap creates a pseudo continues wave like signal that is re-injected into the gain-switched laser

Improved performance of a hybrid radio/fiber system using a directly modulated laser transmitter with external injection

A directly modulated laser diode with external light injection is used to generate microwave optical signals for a hybrid radio/fiber system. The external light injection greatly enhances the frequency response of the laser, and thus, significantly improves the overall performance of the hybrid system. Experimental results show a 14-dB improvement in system performance for the externally injected laser in a hybrid radio/fiber communication link used for distributing 155-Mb/s data signal

Development of highly flexible broadband networks incorporating wavelength division multiplexing and sub-carrier division multiplexing in a hybrid radio/fiber distribution system

A radio over fiber distribution system incorporating both SCM and WDM technologies is presented. The SCM signal contains five 155 Mbit/s data channels, centered around 18.5 GHz with 450 MHz spacing. This signal is directly modulated onto three high-speed lasers with emission frequencies spaced by 50 GHz. Bragg filters are employed at the receiver base station in order both to demultiplex the required optical channel, and to ensure that the detected signal is single side band (in order to overcome dispersion limitations on the link). Our results show negligible degradation in system performance for the demultiplexing of the WDM signal compared with the back-to-back performance curves

Generation of optical microwave signals using laser diodes with enhanced modulation response for hybrid radio/fiber systems

The authors present the idea of using a laser with improved modulation bandwidth to generate microwave optical signals for hybrid radio/fibre systems. External light injection has been used to enhance the frequency response of the laser and thus greatly improve the overall performance of the hybrid system. Experimental results show an 8 dB improvement in system performance for the externally injected laser in a hybrid radio/fibre system used for distributing 155 Mbit/s data signals on an 18 GHz carrie

Generation of widely tunable picosecond pulses with large SMSR by externally injecting a gain-switched dual laser source

The authors demonstrate a procedure of generating picosecond optical pulses that are tunable over a wide wavelength range (65 nm) and have very high spectral purity side-mode suppression ratio [(SMSR)>60 dB]. The large tuning range is obtained by employing external injection into a gain-switched source containing two Fabry-Pe/spl acute/rot lasers. The use of a widely tunable Bragg grating at the output improves the SMSR such that it exceeds 60 dB over the entire tuning range