INNOVATION · Multi-wavelength regeneration technologies for advanced modulation optical signals

Multi-wavelength regeneration technologies for advanced modulation optical signals

With the development of high-speed Internet access, mobile voice and data services, and cloud-based data centers, broadband technologies with the low-cost per transported information bit will speed for the telecommunication infrastructure market of €350 billion and 700,000 jobs in Europe by the year 2020. To meet this exponentially growing volume and bandwidth demand, the fiber communication network uses advanced modulation formats to increase the system capacity. However, when moving to high constellation orders, signals become more vulnerable to transmission impairments, e.g. amplified spontaneous noise (ASE) or Kerr nonlinearity. All-optical regeneration is a promising technology to suppress these impacts and improve the quality of the transmitted signal. Simultaneously suppressing signal distortions on multiple amplitude or phase levels is still a significant challenge in the design of the regenerator subsystem. In a coherent mixer structure phase noise suppression on 4-levels has been demonstrated. On the other hand, only 2-levels amplitude regeneration was achieved in a nonlinear-optical loop mirror (NOLM). Regenerative capability is limited by the multilevel amplitude regenerator. INNOVATION project aims to break through the limitation of current all-optical amplitude regenerator. NOLM unit possesses the power oscillatory nature and can be used as a multilevel amplitude regenerator. However, the stimulated Brillouin scattering effects within the highly nonlinear fiber (HNLF) impede the development of the Kerr-based nonlinear response. We used the pulse signal and the strained aluminous-silicate HNLF to reduce such impact. By carefully optimizing the system parameters we have achieved four plateau regions in a single NOLM unit. Moreover, we proposed a novel subsystem-Conjugated NOLM pair-to combine the NOLM regenerator and the mid-span optical phase conjugator (OPC). Using such all-optical repeater in the long-haul transmission we have successfully extended the transmission reach up to 100%, compared to an un-regenerative link or an OPC link. All-optical regeneration schemes demonstrated in INNOVATION can deal with multi-wavelength advanced modulated signals, which supports the high-capacity long-haul backbone networks.

Data: CORDIS, © European Union