Yoav Yadin

Bit-error rate of optical DPSK in fiber systems by multicanonical Monte Carlo Simulations

The multicanonical Monte Carlo simulation method is applied to phase-modulated optical communications systems. The method is used to estimate the bit-error rate of long-haul differential phase-shift-keying transmission. The simulation results are in good agreement with the predictions of a previously reported theoretical model. Furthermore, the simulations imply that the phase noise, that determines the error rate, can be approximated as Gaussian for many practical cases.

Nonlinear phase noise in phase-modulated WDM fiber-optic communications

Phase-noise statistics in nonlinear dispersive fiber-optic links are examined. The bit-error rate (BER) in phase-modulated transmission is extracted from the phase-noise probability distribution. For differential phase-shift keying systems, we find that the noise distribution, as well as the overall BER, agree well with the Gaussian approximation for a wide range of system parameters. The analysis is validated using Monte Carlo simulations of wavelength-division-multiplexed systems.

Parallel optical interconnects over multimode waveguides

This paper proposes a new multiple-input multiple-output (MIMO) modulation scheme applicable for optical interconnection systems. The method enables parallel transmission of multiple channels over a single multimode waveguide, thus avoiding cumbersome physical multichannel routing. In addition, the proposed method enables possible integration of the transmitter, transmission channel, and receiver using silicon technology, therefore facilitating direct interfacing with silicon circuitry.

Soft detection of multichip DPSK over the nonlinear fiber-optic channel

We analyze the performance of a recently proposed multichip differential phase-shift-keying (DPSK) format over the nonlinear fiber-optic channel. For a single wavelength nonlinear phase-noise-limited channel, a multichip DPSK receiver based on a three-chip observation can attain more than two orders of magnitude bit-error-rate reduction relative to a standard DPSK receiver, or equivalently /spl sim/1-dB improvement in Q-factor, significantly exceeding the 0.2-dB improvement achieved by the same format over a linear optical channel.

Balanced Versus Single-Ended Detection of DPSK: Degraded Advantage Due to Fiber Nonlinearities

We study the effect of nonlinear transmission on the receiver sensitivity advantage of differential-phase-shift-keying systems using balanced detection. We show how the accumulation of nonlinear phase noise owing to the Gordon-Mollenauer effect reduces the advantage of balanced detection, until it is completely eliminated in highly nonlinear scenarios. The results of our analysis are consistent with existing experimental observations

Parallel Optical Interconnects Over Multimode Waveguides Using Mutually Coherent Channels and Direct Detection

We present an approach for parallel optical interconnect channels using a single light source and a single multimode waveguide. Parallel transmission is achieved by exploiting the modal diversity of the multimode waveguide, thus improving the channel density, compared to other optical interconnect schemes. The proposed system facilitates packaging and requires relatively simple components, which can be integrated using silicon technology. The performance of such a system is analyzed for different modulation schemes. Based on the analysis, improved modulation schemes that reduce the system error probability are suggested.

Enhanced Self-Coherent Optical Decision-Feedback-Aided Detection of Multi-Symbol M-DPSK/PolSK in particular 8-DPSK/BPolSK at 40 Gbps

Direct-detection sensitivity for M-DPSK/BPolSK with large M is improved generating self-coherent gain without an actual local oscillator light source by means of a novel optical decision-feedback-aided tapped-delay-line-interferometer, along with a 90deg optical hybrid, and analog-post processing.

Analytical evaluation of bit error rates for hard detection of optical differential phase amplitude shift keying (DPASK)

Recently introduced extensions of differential phase-shift keying (DPSK), referred to here as optical differential phase amplitude shift keying (DPASK), explore an increase in the data throughput for a given bandwidth by effectively multiplexing differential phase encoding and amplitude modulation onto the same fiber link. The DPASK systems proposed and demonstrated so far apply phase and amplitude modulation in tandem, jumping between either two or four equispaced phase values as well as independently selecting between two amplitude levels. In this paper, closed-form expressions for the quantum limits of bit error rate (BER) for such DPASK optical transmission systems are derived for the first time, verifying the analytic expressions by numerical multicanonical Monte Carlo simulations. The resulting quantum-limit sensitivities indicate that the two-level binary phase DPASK incurs a considerable photonic sensitivity penalty in return for its improved spectral efficiency. On the positive side, the more complex quaternary phase DPASK format exceeds the performance of its 8-ary DPSK scheme counterpart.

Multi-Chip Detection of Optical Differential Phase-Shift Keying and Complexity Reduction by Interferometric Decision Feedback

Optical Multi-Chip DPSK realization is dramatically simplified by feeding past decisions back into delay interferometers. Simulations indicate substantial performance improvements for both binary and quaternary DPSK in the linear and nonlinear fiber transmission regimes.

Simplified decision-feedback-aided multichip binary DPSK receivers

We introduce decision-feedback-based novel realizations of substantially reduced complexity for the recently proposed multichip differential phase-shift keying (MC-DPSK) advanced modulation formats, and interpret the operation of the resulting simplified receivers as synthesizing a lower noise reference for differential phase detection. Full propagation simulations indicate that the resulting binary phase MC-DPSK with three (four) chips display a bit-error-rate advantage of nearly three (four) orders of magnitude relative to conventional DPSK over a nonlinear phase fiber channel