Paniz Ebrahimi

Comparison of polarization mode dispersion emulators

We analyze polarization mode dispersion (PMD) emulators comprised of a small number of sections of polarization-maintaining fibers with polarization scattering at the beginning of each section. Unlike previously studied devices, these emulators allow the emulation of a whole ensemble of fibers. We derive an analytical expressions and determine two main criteria that characterize the quality of PMD emulation. The experimental results are in good agreement with the theoretical predictions.

Silicon photonic tunable optical dispersion compensator

A silicon photonic tunable optical dispersion compensator (TODC) is demonstrated based on a series of 5 thermally tunable Mach- Zehnder interferometers. The TODC has a 2.8mm x 5.0 mm foot-print with continuously tunable dispersion from 0ps/nm to 2000ps/nm with a low tuning power of 80mW. This TODC is used to extend the reach of a 10Gb/s link from 85km to 150km.

Multi-format Continuously Variable Bitrate DPSK/OOK Demodulating Receiver Design

In this paper we demonstrate a continuously variable bitrate receiver from 10 to 40 Gbit/s for DPSK balanced demodulation. Unlike previous DPSK demodulators, this receiver is also capable of passing intensity modulated waveforms unaffected.

Increasing the bit rate in OCDMA systems using pulse position modulation techniques

We have experimentally demonstrated two novel pulse position modulation techniques, namely Double Pulse Position Modulation (2-PPM) and Differential Pulse Position Modulation (DPPM) in Time-Wavelength OCDMA systems that will operate at a higher bit rate compared to traditional OOK-OCDMA systems with the same bandwidth. With 2-PPM technique, the number of active users will be more than DPPM while their bit rate is almost the same. Both techniques provide variable quality of service in OCDMA networks.

Doubling the number of active users in a 2-D t-/spl lambda/ O-CDMA network using a hard limiting receiver

We analytically show that using a receiver in a 2-D time-wavelength asynchronous O-CDMA system, can double the numbers of active users by reducing multiple-access-interference. Utilizing our results we generate design rules for O-CDMA code-sets in hard-limiting-receiver.

Tunable wavelength demultiplexer and OCDMA code hopping using a 10-/spl mu/s-tuning MEMS-actuated Gires-Tournois filter

We demonstrate system level performance and rapid switching (10 mus) of a 1times3 wavelength multiplexer/demultiplexer (mux/demux) based on a Gires-Tournois interferometer with cyclically tunable center wavelengths. Group delay ripple within the passband is measured to be <8 ps. Less than 0.5-dB power penalty is observed for 10-Gb/s data propagating through the demux. Additionally, rapid optical code-division multiple-access code hopping using this tunable demux has been shown

A 10-Gbit/s EML link using detuned narrowband optical filtering.

In this paper, the effects of asymmetric narrowband optical filtering are investigated in a 10-Gbit/s optical communication link using integrated electro-absorption modulated lasers (EML). We investigate the effect of EML chirp on link performance as well as the optimal filter bandwidth and wavelength detuning. We show that both the phase response and the spectral narrowing of the filter will enable a longer distance transmission by interacting with the EML transient chirp and compensating for the fiber chromatic dispersion. Experimentally, an 8.75-GHz filter is shown to improve the link distance by 40 km from 65 to 105 km, when transmitting over standard single mode fiber.

Differential-Pulse-Position-Modulation (DPPM) in OCDMA Networks to Achieve Higher Data-Rate/User

We have experimentally demonstrated the use of differential-pulse-position-modulation (DPPM) format in OCDMA networks. We have achieved 3 users at 5 Gb/s data rate that is 8 times faster than conventional OCDMA for 16-chip OCDMA codes.