RTU Research Information System
Latviešu English

Innovation application: Optical Signal Regeneration Using the Advanced Mamyshev Type Regenerator

Title Optical Signal Regeneration Using the Advanced Mamyshev Type Regenerator
Abstract

Optical signal degrades considerably during its propagation inside the fiber link. It is caused by many factors: fiber attenuation, chromatic and polarization mode dispersion that broadens the pulses, accumulated amplified spontaneous emission (ASE) that is a broadband noise source induced by amplifiers and nonlinear optical effects. Optical amplifiers compensate fiber losses therefore the amplification may be considered as the first level regeneration of optical signal. But amplifiers also degrade the signal by adding ASE noise and timing jitter. It is acceptable for a single stage amplification but becomes unacceptable for signal transmission over long distances with several amplification stages. Therefore there is a need for regenerators that also perform restoration of the signal shape or so called 2R regenerators (reamplifying and reshaping). Reshaping increases the SNR that is very essential to guarantee faultless transmission of signals.

Keywords optical signal distortions, self-phase modulation effects, optical signal regenerator
Authors Andis Supe
Jurģis Poriņš
Department (13100) Telekomunikāciju institūts
Statistical Classification of Economic Activities, NACE 2 Telecommunications
Description of the technology

Optical 2R regenerator working principle is based on nonlinear optical effect: self-phase modulation (SPM). SPM leads to an intensity-dependent nonlinear phase shift φNL. But a temporally varying phase takes the form as change of instantaneous optical frequency across the pulse from its central value ω0 that is also called as frequency chirp. Therefore SPM causes signal spectral broadening that is a very essential part of the regeneration process. Proposed regenerator setup consists of erbium doped fiber amplifier (EDFA) that boosts the input signal to power level required to achieve desired spectral broadening due to SPM in a highly nonlinear optical fiber (HNLF) span. After the HNLF there is a tunable bandpass optical filter. Tunable filter enables alignment of the filtering central wavelength and the pass-band width.

Fig. 1. Optical 2R regenerator scheme.

Applications This type of regenerator can be used in amplitude modulated return to zero (RZ) coded signal optical transmission systems by replacing existing optical amplifiers. This would improve the quality of broadcast signal that allows to increase transmission distance and or data transmission rate.
Advantages

The proposed signal regenerator is reconfigurable and therefore suitable for different data transmission rate signal restoration in single channel and multichannel systems. This regenerator also has additional functionality that is related to signal wavelength conversion.

Technology Readiness Level System complete and qualified
Partnership offer • Service contracts.
Publications
ID 49
Contact information Linda Šufriča, e-mail: inovacijas@rtu.lv; phone.: 28442736