Abstract—In this paper, based on the coupled-mode and carrier rate equations, derivation of a dynamic model and numerically analysis of a MQW chirped DFB-SOA all-optical flip-flop is done precisely. We have analyzed the effects of strains of QW and MQW and cross phase modulation (XPM) on the dynamic response, and rise and fall times of the DFB-SOA all optical flip flop. We have shown that strained MQW active region in under an optimized condition into a DFB-SOA with chirped grating can improve the switching ON speed limitation in such a of the device, significantly while the fall time is increased. The values of the rise times for such an all optical flip-flop, are obtained in an optimized condition, areas tr=255ps. Keywords—All-Optical Flip-Flop (AO-FF); Distributed feedback semiconductor optical amplifier (DFB-SOA); Optical Bistability; Multi quantum well (MQW). I. INTRODUCTION PTICAL networks have become an important part of the global telecommunication networks. In such networks, signals are transmitted through optical fibers and are switched by cross-connects. Transmission technologies have been developed by great advances in dense wavelength division multiplexing (DWDM). A DWDM system allow that more than a hundred wavelengths to be simultaneously launched into a single optical fiber. However, the electronic packet routers in the cross-connects face challenges in terms of power consumption, cost, and switching speed [1]. However, all optical switching is appearing as a promising technology, because it can overcome the challenges of its electronic counterpart. Gradually, more switching functions will be implemented in optical domain by using all optical integrated circuits. For this reason, advances in all-optical signal processing technologies are essential for future all optical packet-switching nodes [1]. In an all-optical packet switch, M. Jabbari is with Electrical Engineering Department Marvdasht branch, Islamic Azad University, Marvdasht, Iran. (Corresponding author: phone: +98711-8218809; Jabbari@miau.ac.ir) M. K. Moravvej-Farshi is with Advanced Device Simulation Lab (ADSL), Electrical and Computer Engineering Department, Tarbiat Modares University (TMU), P. O. Box 14115-143, Tehran, 1411713116, Iran. R. Ghayour is with Electrical Engineering Department, Shiraz University Shiraz, Iran. A. Zarifkar is with Iran Telecommunication Research Center, P. O. Box 14155-3961 Tehran, 1439955471, Iran. first the optical label is taken from the receiving packet and converted to a parallel signal, then it is applied to an optical flip-flop, and afterward the optical output from the flip-flop enters an all-optical switch. Thus, without any optoelectronic conversion, the optical packets are switched fully in optical domain. This configuration provides us an ultra fast switching due to high speed operation of both the optical flip-flop and all-optical switch [2]. Also, the latching capability of all optical flip-flops allows the output to be preserved for processing at a later time and can be used in sequential processes such as bit-length conversion, re-timing, and data- format changing [3]. Recently, various all-optical flip-flops (AOFFs) have been proposed [3-10]. Such AOFFs are based on different structures such as a distributed feedback semiconductor optical amplifier (DFBSOA) [3], a SOA mutually connected to a DFB-laser diode [4-6], a single quarter wavelength shifted (QWS) DFB laser diode [7], an optically bistable integrated SOA and DFB-SOA [8], a bistable QWS-DFB semiconductor laser amplifier with tapered grating [9], and a bistable DFB semiconductor laser amplifier [10]. When a distributed feedback semiconductor laser diode is biased below its oscillation threshold, it acts as a DFB-SOA and shows a dispersive optical bi-stability (OB) behavior [7]. This device suffers from low speed due to the high carrier life time. Although the intrinsic carrier life time is in the order of few hundred picoseconds, the effective carrier lifetime can be decreased by stimulated emission. Reducing effective carrier life time can be achieved by increasing the waveguide confinement (Γ) and the material differential gain. This can be done through a thicker active region including a thick InGaAsP quaternary or a large number of quantum wells [11]. Increasing the photon number in the DFB-SOA is another way to reduce the effective carrier life time. Introduction of an additional holding beam (Assist light) is creating a large number of photons in the DFB-SOA [12]. Previously Maywar et al. proposed the non uniform linear chirp grating DFB-SOA to improve the steady state behavior [3]. Also we investigated the linear chirped DFB-SOA all optical flip flop (DFB-SOA-AOFF) switching based on cross phase modulation (XPM) and optimized the device parameters to gain minimum switching ON and OFF times [12]. In this work, we numerically applied single and multiple strained XPM Response of Multiple Quantum Well chirped DFB-SOA All Optical Flip-Flop Switching Masoud Jabbari, Mohammad Kazem Moravvej-Farshi, Rahim Ghayour, and Abbas Zarifkar O World Academy of Science, Engineering and Technology International Journal of Electrical and Computer Engineering Vol:3, No:8, 2009 1584 International Scholarly and Scientific Research & Innovation 3(8) 2009 scholar.waset.org/1307-6892/4651 International Science Index, Electrical and Computer Engineering Vol:3, No:8, 2009 waset.org/Publication/4651