A New Eye Mask for Seeded DWDM Transmission Links Syed Aun Abbas*, Han Hyub Lee**, Hee Yeal Rhy* *Ericsson-LG R&D Center, 533, Hogye 1-dong, Dongan-gu, Anyang-shi, Gyeonggi-do, 431-749, South Korea heeyeal.rhy@ericssonlg.com syed.abbas@ericssonlg.com **Electronics and Telecommunications Research Institute 218 Gajeongno, Yuseong-gu, Daejeon, 305-700, South Korea hanhyub@etri.re.kr Abstract—THE FACTORS THAT INFLUENCE THE CHOICE OF A SUITABLE EYE MASK FOR A SEEDED DWDM LINK ARE PRESENTED. IT IS OBSERVED THAT TWO FACTORS PLAY A KEY ROLE IN DETERMINING THE CHARACTERISTICS OF THE EYE MASK NAMELY, BANDWIDTH OF THE TRANSMITTER DRIVER CIRCUIT AND THE TRANSMITTER RIN IN CONJUNCTION WITH THE INPUT SEED SIGNAL POWER. NONE OF THE WELL KNOWN EYE MASKS FIT WELL DUE TO THICKER ONES LEVEL IN A SEEDED DWDM SYSTEM, SO THERE IS A NEED TO DEFINE A NEW MASK FOR THIS PURPOSE. IT IS SHOWN THOROUGH MEASUREMENT RESULTS THAT AN EYE MASK DERIVED FROM THE NRZ 10G RATIO SMALL MASK DEFINED IN ITU-T RECOMMENDATION G.959.1 CAN SERVE THE PURPOSE. Keywords- (Seeded DWDM, G.698.3, Eye Mask) INTRODUCTION The need for a low cost metro DWDM network prompted ITU-T Study Group 15 Question 6 to investigate a suitable new architecture and technologies in June 2010. This resulted in the consent of a new ITU-T Recommendation, G.698.3 entitled “Multichannel DWDM applications with single channel optical interfaces” in the December 2011 meeting of the ITU-T SG15, [2]. This Recommendation facilitates the use of a colour agnostic transmission device in the Tail-End Equipment (TEE) for easy management and operation. This Recommendation allows for a maximum channel insertion loss of 14dB. The maximum transmission distance is limited to approximately 40 kilometers, with a 10 -12 Bit Error Ratio (BER). The Architecture of the G.698.3 seeded DWDM system is shown in Figure 1 [2]. It consists of three major parts; head-end, tail-end and black link. The Head-End Equipment (HEE) consists of a combination of OD/OM (Optical De-multiplexer/Optical Multiplexer), a seed source, and optical transceivers. It is typically located at a network operator’s CO (Central Office). The interface between the head-end and the black link is defined as MPI- S M /MPI-R M . The head-end can be implemented in many different ways: An Arrayed Waveguide Grating (AWG) can be used as OD/OM with a suitable diplexer WDM filter. Alternatively, a separated OD and OM (or two AWGs) can be used for easy realization of integration. The transmitter can be either a seeded reflective modulator or a conventional WDM transmitter based on a DFB laser. A suitable device can be used to couple the seed source to the black link. The seed source can be implemented in a number of ways including pumped Erbium doped fibre, a super-luminescent light emitting diode (SLED) or a multi- wavelength laser source. These sources have their own pros and cons depending on the operational wavelength and output power requirements. In some cases, the main system performance limitations are also due to these sources.  The black link consists of the transmission fibres and the OD/OM. An Arrayed Waveguide Grating (AWG) is a typical implementation for the OD/OM in the black link. The interface between tail-end and black is defined as R S /S S . The tail-end comprises a reflectively modulating optical transceiver. An anti-reflection coated FP LD (Fabry Perot Laser Diode), RSOA (Reflective Semiconductor Optical Amplifier), or REAM (Reflective Electro- 2012 10th International Conference on Frontiers of Information Technology 978-0-7695-4927-9/12 $26.00 © 2012 IEEE DOI 10.1109/FIT.2012.60 298