**9. References**


Potential cost effective solutions for next generation of access network could be based on RSOA devices. Therefore, research on RSOA devices is driven by WDM-PON applications. It is of prime interest to solve issues related to this application. RSOAs as colourless ONU have been investigated for access network. High performances RSOAs enable an upstream transmission of 8 WDM channel at 2.5 Gbit/s over 45 km. A high optical budget (36 dB) was

The chirp remains one major limiting factor as well as the modulation speed. 2-section RSOAs were used to overcome the first drawback. The use of 2-section RSOAs allows a 100 km transmission below the FEC limit at 2.5 Gbit/s. Finally, long RSOA allows performing the first direct 10 Gbit/s modulation with open eye diagram thanks to the E/O modulation

Therefore, as a general conclusion, RSOAs show a great potential as a next generation of optical transmitter. It is a colorless device which can be used in WDM access networks. However the modulation speed is still limited and 10 Gbit/s modulation needs to be

Tech-eco analysis has to be performed in order to evaluate the different technologies for WDM-PON and a trade-off between performances and cost will determine the future of optical access network. RSOA are still limited in terms of performances and architecture but

The work in this chapter would not have been possible without the support of numerous people and I would like to acknowledge a few of them here. Firstly, the author would like to

Next I would like to thank fellow workers at III-V lab, especially Francis Poingt and Marco Lamponi who worked closely with me. This collaboration was key to the success of this study. Additionally, I wish to acknowledge Dr. Philippe Chanclou for the fruitful

An F.T, Soo Kim K., Gutierrez D., Yam S., Hu E., Shrikhande K., & Kazovsky L.G.

Brenot R., Provost J.-G., Legouezigou O., Landreau J., Pommereau F., Poingt F.,

Buldawoo N., Mottet S., Le Gall F., Sigonge D., Meichenin D., & Chelles S. (1997), "A

Chanclou P., Payoux F., Soret T., Genay N., Brenot R., Blache F., Goix M., Landreau J.,

networks", *in Proc. ECOC*, 2007, pp. 1-2, Berlin, Germany

*Proc. ECOC'97*, Sept. 1997, pp. 196-199, Edinburgh, UK

(2004),"SUCCESS: A Next-Generation Hybrid WDM/TDM Optical Access Network Architecture", *J. Lightwave Technol.*, Vol. 22, No. 11, November 2004 Brenot R., Pommereau F., Le Gouezigou O., Landreau J., Poingt F., Le Gouezigou L.,

Rousseau B., Lelarge F., Martin F., & Duan G-H (2005), "Experimental study of the impact of optical confinement on saturation effects in SOA", *in proc. OFC 2005*,

Legouezigou L., Derouin E., Drisse O., Rousseau B., Martin F., Lelarge F., & Duan G.H. (2007), "High modulation bandwidth reflective SOA for optical access

Semiconductor Laser Amplifier-Reflector for the future FTTH Applications", *in* 

Legouezigou O., & Mallécot F. (2007), "Demonstration of RSOA-based remote

new approach such as self-seeding could overcome these main issues.

thank Dr. Romain Brenot for his guidance and advices.

demonstrated.

bandwidth increase.

**8. Acknowledgements** 

discussions.

**9. References** 

OME50, March 2005

realised over a minimum of ten kilometres.

modulation at 2.5 and 5 Gbit/s for WDM PON", *in Proc. OFC*, OWD1, 2007, Anaheim, USA


**2** 

*China* 

**High-Speed All-Optical Switches** 

*The State Key Laboratory of Advanced Optical Communication Systems and Networks,* 

Lots of research efforts have been focused to realize all-optical high-speed switches through nonlinear optical elements, for instance, high nonlinear fibers (HNLF), nonlinear waveguides as well as semiconductor optical amplifiers (SOAs). All-optical switches incorporating SOAs is one of the particularly attractive candidates due to their small size, high nonlinearities (low switching energy required) and ease of integration. All-optical switches also keep the network transparent, enhance the flexibility and capacity in network, and offer the function of signal regeneration, therefore SOAs provide various attractive alloptical functions in high-speed signal processing in fiber communication systems (Stubkjaer, 2000; Poustie, 2007), including all-optical AND/XOR logic gates, wavelength conversion (WC), optical-time division multiplexing (OTDM) de-multiplexing, optical signal regeneration and so on, which will be essential to the implementation of future wavelength

However, the operation speed of SOA based switches is inherently limited by its relative slow carrier lifetime (in an order of 100 ps) (Manning et al., 2007). Various schemes have been proposed to enhance the operation speed of SOA-based all-optical devices, for instance, 160 Gb/s and 320 Gb/s wavelength conversion was reported by using a detuned narrow band-pass filter to spectrally select one of the side-bands (blue-shifted or redshifted) of the output signal (Liu et al., 2006, 2007). In this case, the SOA operation speed can be increased via the chirp effect on the SOA output associated with the SOA ultrafast gain dynamics. It has been shown that, the CW modulation response time has been reduced from 100 ps to 6 ps via filter detuning (Liu et al., 2006, 2007). Although using a detuned filter after the SOA can improve the optical signal-to-noise ratio (OSNR) of the output when comparing with the case of using a non-detuned filter (Leuthold, 2002), however the OSNR of the output signal will degrade to a large extent since the optical carrier was suppressed. Recently, all-optical high-speed switches based on the cascaded SOAs were proposed and demonstrated. In Fig. 1, an all-optical switch incorporating two cascaded SOAs was proposed as an alternative high-speed technique, which was dubbed as "turbo-switch" (Manning et al., 2006; Yang et al., 2006, 2010), while preserving the OSNR of the output signal. An error-free wavelength conversion was demonstrated at 170 Gb/s (Manning et al., 2006). In addition, the operating speed of an all-optical XOR gate was also demonstrated at

division multiplexing (WDM) or optical packet switching (OPS) networks.

**1. Introduction** 

**Based on Cascaded SOAs** 

 *Shanghai Jiao Tong University, Shanghai,* 

Xuelin Yang, Qiwei Weng and Weisheng Hu

