Dániel Mazroa

Phase-squeezing properties of non-degenerate PSAs using PPLN waveguides

We investigate the phase squeezing characteristics of non-degenerate phase-sensitive-amplifiers (PSAs) based on periodically-poled-lithium-niobate (PPLN) waveguides. We implement two PSA configurations with phase insensitive idler generation performed in both highly-non-linear-fiber (HNLF) and PPLN waveguides. In both cases we demonstrate regeneration of a noisy BPSK signal, despite net signal attenuation in the phase sensitive PPLN, and show that the level of phase squeezing varies with the phase sensitive dynamic range (PSDR). We observe that weak idler generation in the PPLN limits the achievable PSDR and that use of HNLF for idler generation leads to the largest PSDR. However, in phase regeneration measurements we observe that the pump phase modulation, required to overcome stimulated Brillouin scattering, adds significant amplitude noise, which increases with the PSDR.

Large Phase Sensitive Gain in Periodically Poled Lithium–Niobate With High Pump Power

We investigate phase-sensitive operation at telecommunication wavelengths in periodically-poled lithium-niobate waveguides, measuring a record phase-dependent dynamic range of 14.5 dB with 5-dB phase-sensitive gain, compared to phase-insensitive operation. We also highlight limitations arising at high pump powers from green light emission and thermal instability which limits performance compared with an ideal theoretical model.

Investigation of an All-Optical Black-Box PPLN-PPLN BPSK Phase Regenerator

We investigate the phase squeezing performance of an all-optical black-box binary phase-shift keyed phase regenerator constructed from periodically-poled lithium-niobate (PPLN) waveguides. Phase regeneration is performed with different levels of phase noise and constant amplitude noise added to the phase modulated input. We experimentally show that, for moderate phase noise, unwanted phase-to-amplitude noise conversion can be minimized without degradation of the phase squeezing performance, by controlling the signal-to-pump power ratio at the input to the PPLN-based phase-sensitive regenerator.

Physical impairments of monitoring trails in all optical transparent networks

In recent years, following the deployment of WDM networks, fault detection and localization has become a challenging issue in networks with high reliability. Optical layer monitoring schemes based on monitoring trail (m-trail) is considered a promising approach localizing single link failure unambiguously in all optical networks. Although the extensive works on the m-trail concept, the issue has not been validated from the feasibility point of view. Previous works on the m-trail monitoring scheme have focused on algorithm design for minimizing the number of monitors, however, none of them has observed the physical limitations. In this paper, we investigate the physical constraints on launching m-trails, mainly focusing on the maximum length each m-trail may have. Numerous simulations were implemented in VPI Transmission Maker Simulation Tool for observing qualitative parameters in different m-trail length. In our simulation, we could validate the feasibility of 15000 km long m-trails when out-of-band monitoring is used.

Numerical Comparison of WDM Interchannel Crosstalk in FOPA- and PPLN-Based PSAs

We propose a model and numerical simulations to calculate crosstalk (XT) between multiple wavelength-division-multiplexing (WDM) channels in copier + phase sensitive amplifier (PSA) chains based on periodically poled lithium niobate (PPLN). The calculated XT is compared with XT generated in copier + PSA chains based on highly nonlinear fiber (HNLF). For ordinary device parameters, the results show that for an increasing channel number, the growth of interchannel XT in PPLN is less rapid compared with HNLF, as a consequence of the finite quasi-phase matching band of PPLN. This ensures lower XT in PPLN-based chains for 18 channels, whereas HNLF chains show better XT performance for 4 channels.

Multi-channel phase squeezing in a PPLN-PPLN PSA

We investigate phase squeezing of up to four signal channels in a non-degenerate phase-sensitive amplifier constructed from periodically-poled-lithium-niobate waveguides and observe that additional channels have little impact the phase squeezing performance.

Phase-sensitive amplification in a single bi-directional PPLN waveguide.

We investigate phase-sensitive amplification (PSA) and phase regeneration of a binary phase-shift keying (BPSK) signal using a single periodically poled lithium niobate (PPLN) waveguide. The PPLN is operated bi-directionally in order to simultaneously achieve phase correlated signals and phase-sensitive (PS) operation. We use injection-locking for carrier phase recovery and a lead zirconate titanate (PZT) fiber stretcher to correct path length deviations in the in-line phase regenerator. We observe a trade-off between high PS gain provided by high pumping power and stability of the device.

Investigation of black-box phase regeneration using single bi-directional PPLN waveguide

We investigate a novel in-line phase regeneration set-up using a single bi-directional PPLN waveguide for both generation of phase correlated signals and phase-sensitive regeneration and injection-locking for carrier phase recovery.

Signal-signal crosstalk measurements in a PPLN-PPLN PSA with narrow channel spacing

We investigate inter-channel interference as a function of channel-spacing for PSAs constructed from PPLN waveguides. We use 9*50GHz spaced input channels and show that the second order non-linearity can be advantageous for multi-channel PSA applications.

Evaluation of a fiber-optic parametric amplifier with optical feedback in multi-channel dynamic networks

We investigate the feasibility of optical gain-clamping a fiber-optic parametric-amplifier to prevent cross gain saturation in multi-channel systems. We measure only moderate improvement but identify potential for gain-control in non-data applications.