Shifeng Jiang

New model of noise figure and RIN transfer in fiber Raman amplifiers

A new and complete analysis of noise figure and pump noise transfer in fiber Raman amplifiers is reported. Our approach is based on vacuum fluctuation which is the minimum level of the optical noise. As a result, the model enables us to represent both the intrinsic noise of the amplifier as the amplification of the input vacuum fluctuation, the amplification plus attenuation noise addition, and the extrinsic noise due to the noise transfer from the pump.

Self-referenced and single-ended method to measure Brillouin gain in monomode optical fibers

We present a new self-referenced and single-ended method to measure the Brillouin-gain coefficient in monomode optical fibers accurately with high reliability. Our comparative measurements on several different fibers show that a fiber with a smaller optical effective mode area can nevertheless have a higher Brillouin threshold, thus confirming the significance of acousto-optic effective mode area.

Signal and Quantum Noise in Optical Communications and Cryptography

Abstract Fundamental quantum noise manifestations in optical amplification, optical direct detection and coherent detection systems are presented from the physics and information theory basics to their system limitation or impairments. Application to optical communications and quantum cryptography will be discussed in relation to classical technical system impairments.

Bit-Error-Rate Evaluation of the Distributed Raman Amplified Transmission Systems in the Presence of Double Rayleigh Backscattering Noise

A new exact bit-error-rate evaluation method for distributed Raman amplification transmission systems in the presence of both amplified spontaneous emission and double Rayleigh backscattering (DRB) is developed based on a study of statistical characterization of DRB

Full characterization of modern transmission fibers for Raman amplified-based communication systems.

Telecommunication carriers have to estimate the Raman parameters of the fibers installed on their optical transport networks in order to facilitate the design of the next generation of high bit-rate Raman amplified-based transmission systems. This paper reports a very complete characterization of the most popular modern transmission fibers in terms of Raman efficiency, noise figure and double Rayleigh backscattering crosstalk. Our experiment is based on an averaged power analysis, applied to a counter-pumped long-haul distributed fiber Raman amplifier. We evaluate as well at 40 Gb/s for these different fiber types the double Rayleigh backscattering impact in terms of Q-factor penalty for various Raman gains and RZ modulation formats with different duty cycles.

Theoretical Analysis on the PMD-Assisted Pump-to-Signal Noise Transfer in Distributed Fiber Raman Amplifiers

A theoretical analysis on the pump-to-signal noise transfer, in the presence of the polarization mode dispersion in the distributed fiber Raman amplifiers, is presented. We analytically show the impact of temporal fluctuations of the pump state of polarization on the relative intensity noise of the amplified signal. The system performance degradations are then estimated with analytical expressions.

A Fourier Series Approach to Analyze Pump Modulation Induced Noise in Raman Amplifiers With TDM Pumps

In this letter, Raman amplifiers (RAs) with time-division-multiplexed (TDM) pumps are analyzed using a computational cost-effective Fourier series approach. Analytical approximate formulas are derived based on this model. These formulas bring deep insight into the pump modulation induced noise (PMIN) in TDM pumped RAs. Moreover, the approach allows the analytical analysis of the TDM pumped RAs with multiple pumps while previous analytical studies mostly focused on the single pump and single signal channel case. By optimizing the pumping order of the multiple pumps, more than 3-dB reduction of the PMIN can be achieved. For short fibers, by properly choosing the modulation frequency, more than 3-dB reduction of the PMIN can be realized.

General formulation for quantum macroscopic nonlinear optics

We present a general formulation for quantum macroscopic nonlinear optics, which can be considered as a fully quantized version of its semiclassical counterpart in which the electric field is treated as the classical variable. Our formulation begins with the fundamental minimal-coupling Lagrangian, which is then transformed into the multipolar Lagrangian. After a quantum preservative expansion by using a Hamiltonian decomposition proposed in this paper, we have found the formal relations between the Heisenberg operators of macroscopic polarization density and macroscopic electric field. Finally, the linearized quantum effects for nonlinear optics are also discussed.

Noise in distributed Raman amplification

Fundamental noise limitations of distributed quantum amplifiers are discussed. For Raman amplifier pumps to signals noise transfer, Rayleigh backscattering and polarization fluctuations of the pump are additional noise sources, which are discussed including their impact on system performances.

PMD Assisted Pump to Signal Noise Transfer in Distributed Fiber Raman Amplifiers

We present a theoretical analysis on the PMD assisted pump to signal noise transfer in distributed fiber Raman amplifiers. New noise mechanisms are pointed out, and their impacts on the system performance are then analyzed.