Performance Assessment of 1310 to 1550 nm Wavelength Conversion

We report on all-optical 1310 to 1550 nm wavelength conversion and NRZ-to-RZ data format conversion based on nonlinear polarization rotation in a single semiconductor optical amplifier. Introduction Undoubtedly, the 1310 nm transmission window is experiencing renewed interest. Multi-Gbit/s 1310 nm transmission technology is employed in access and metro networks [1-2]. The long-haul core network is traditionally centered on the 1550 nm transmission window. Moreover, the core network transmission systems operating at bit rates of higher than 40 Gbit/s usually transmit return-to-zero (RZ) bits with a pulse duration of a few picoseconds and utilizing optical time domain multiplexing (OTDM) technology. As a result, a new network subsystem is required to interface access-metro systems utilizing the whole low-loss bandwidth of silica fibre with the 1550 nm based core network. An ultra wideband wavelength and data format conversion subsystem should offer all-optical multi-Gbit/s wavelength and data format conversion capability to avoid the bottleneck of optical-electrical-optical conversion, while remaining cost-effective. Several ultra wideband wavelength upconversion techniques have been reported to date e.g. [3-4]. Nonlinear polarization rotation in a transparency region of the semiconductor optical amplifier (SOA) is a promising candidate to realize cost-effective multi Gbit/s wavelength up-conversion from the gain region of the SOA [5]. In this letter, we present new results that clearly demonstrate the potential of this concept within alloptical telecommunication networks. We asset experimentally the static and dynamic performance of 1310 to 1550 nm wavelength conversion based on nonlinear polarization rotation in a transparency region of the single SOA. The measurements concerning inverted and non-inverted up-conversion are shown. A wavelength up-conversion with simultaneous NRZ-to-RZ data format conversion is demonstrated for the first time. Setup An all optical 1310 to 1550 nm wavelength and NRZto-RZ data format converter setup is depicted in the dashed box of Fig. 1. The subsystem is made from a 1310 nm SOA (active length 800 μm), wideband couplers (WCs), polarization controllers (PCs), a 1550 nm signal source, and a polarization filter formed by a polarization controller in combination with a polarization beam splitter (PBS). The SOA is in general a birefringent device. The injected 1310 nm light introduces additional birefringence in the 1310 nm SOA via carrier density changes [6]. This causes the transverse magnetic (TM) and the transverse CW @ 1310 nm CW or clock @ 1550 nm 13 10 n m /1 55 0 nm W id eb an d C ou pl er 13 10 n m /1 55 0 nm W id eb an d C ou pl er PC1 PC2