O.H. Adamczyk

Statistics of PMD-induced power fading for intensity-modulated double-sideband and single-sideband microwave and millimeter-wave signals

Polarization-mode dispersion (PMD) can severely degrade the performance of millimeter-wave fiber-optic links by inducing a power fading penalty of the received signal that is dependent on the subcarrier frequency and accumulated PMD along the fiber. We experimentally investigate the statistics of PMD-induced power fading as a function of the differential group delay (DGD) for intensity-modulated double- and single-sideband subcarrier-multiplexed signals in the absence of chromatic dispersion. We find a similar susceptibility to PMD-induced power fading for both modulation formats with a subcarrier frequency of 7 GHz using a PMD emulator with a Maxwellian distribution of DGD (average DGD /spl sim/40 ps). A significant improvement in the worst case power fading penalty (/spl sim/20 dB) is achieved by using an electronically controlled polarization controller in combination with a single section of polarization maintaining fiber in a dynamic first-order PMD compensator. Furthermore, the results of numerical Monte Carlo simulations support the measured data and show the scalability of PMD-induced power fading for subcarrier-multiplexed signals in the microwave and millimeter-wave region.

Distance-independent microwave and millimeter-wave power fading compensation using a phase diversity configuration

We use a nonlinearly chirped fiber Bragg grating in a phase diversity configuration to achieve distance-independent microwave and millimeter-wave dispersion-induced power fading compensation for double-sideband subcarrier-multiplexed systems. We demonstrate compensation for power fading over 150 km at 8 and 12 GHz, with received subcarrier power in all cases uniform to within 1 dB.

Wavelength conversion of subcarrier channels using difference frequency generation in a PPLN waveguide

The authors demonstrate and characterize a transparent all-optical wavelength conversion process for subcarrier-multiplexed channels. Their memoryless /spl chi//sup (2)/:/spl chi//sup (2)/ difference-frequency-generation process uses 1550-nm pumping in a periodically poled lithium niobate waveguide. They achieve penalty-free all-optical wavelength conversion of two 55-Mb/s subcarrier channels. The process shows a >30-dB linear dynamic range for crosstalk-free transparent operation.

Enhanced PMD mitigation using forward-error-correction coding and a first-order compensator

We demonstrate that forward-error-correction combined with a first-order compensator can greatly improve system performance over a wide range of polarisation mode dispersion (PMD). Both the experimental and theoretical results show that the system PMD tolerance limit can be increased to more than 40 ps in 10 Gb/s systems.

Statistics of PMD-induced power fading for double sideband and single sideband subcarrier-multiplexed signals

We experimentally and numerically compare the statistics of power fading for double sideband (DSB) and single sideband (SSB) subcarrier-multiplexed signals under high polarisation mode dispersion (PMD) conditions (average differential group delay (DGD) 40 ps) with and without dynamic first-order polarisation mode dispersion (PMD) compensation. We find that both SSB-SCM and DSB-SCM subcarrier multiplexed signals exhibit similar sensitivity to PMD-induced power fading. Reduces the worst case fading penalty by -20 dB.

Dispersion division multiplexing in subcarrier modulated data transmission using channel-specific RF fading

We demonstrate a novel all-optical multiplexing technique for doubling the usable spectral bandwidth and number of channels in subcarrier-modulated data transmission over optical fiber. By taking advantage of the chromatic-dispersion-induced RF power fading of a given subcarrier frequency, we transmit two subcarrier channels that occupy the same frequency space. This is accomplished by designing the dispersion of each subcarrier channel in a system such that one subcarrier channel can be >99% faded at the same time that another subcarrier can be recovered. We have successfully transmitted and received two 155-Mb/s data channels that are both located at 7.1 GHz and on the same optical carrier wavelength.

Optical subcarrier-multiplexing for output-port contention resolution

We demonstrate an all-optical contention resolution technique that combines two identical-wavelength contending 2.5 Gbit/s channels into the same output-port wavelength channel. This is achieved by optically up-converting one channel to a higher microwave frequency beyond the other channels baseband signal and routing both channels out the desired output-port wavelength channel simultaneously. By using narrow (/spl sim/5 GHz) fiber Fabry-Perot filters for optically demultiplexing the two channels, we recover each channel using a baseband receiver with <1 dB power penalty.

Distance-independent RF fading compensation using a tunable nonlinearly-chirped FBG in a phase diversity configuration

We use a nonlinearly-chirped fibre Bragg grating (FBG) in a phase diversity configuration to achieve distance-independent RF power fading compensation for double sideband (DSB) subcarrier-multiplexed systems. We demonstrate compensation for RF power fading from 0 to 150 km for 8, 10 and 12 GHz, with received RF power in all cases flat to within 1 dB.