**5. References**


**Part 3** 

**Optical Communications Systems: Multiplexing and Demultiplexing** 

162 Optical Communications Systems

This work is a joint study of Norio Tanaka and Shigeru Takarada of Dainichiseika Color & Chemicals Mfg. Co., Ltd., Noriyasu Siga and Kazuya Ohta of Trimatiz, Ltd., Hirofumi Watanabe, Toshimasa Tamura and Keiji Negi of Inter Energy Co., Ltd. and Masaki Kubo of

Hiraga, T.; Ueno, I.; Nagaeda, H.; Shiga, N.; Watanabe, H.; Futaki, S. & Tanaka, N. (2008).

Hiraga, T.; Ueno, I.;Siga, N.; Watanabe, H.;Futaki, S.; Kubo, M.; Takarada, S.;Tanaka, N. (

Tanaka, N.; Ueno, I.; Hiraga, T.; Tanigaki, N.; Mizokuro, T.; Yamamoto, N. & Mochizuki, H.

Tanaka, N.; Ueno, I.; Hiraga, T.; Tanigaki, N.; Mizokuro, T.; Yamamoto, N. & Mochizuki, H.

Ueno, I.; Tsujita, K.; Chen, G.; Tanaka, N.; Takarada, S.; Yanagimoto, H.; Moriwaki, D.; Mito,

Ueno, I.; Hiraga, T.; Mizokuro, T.; Yamamoto, N.; Mochizuki, H. & Tanaka, N. (2007).

Ueno, I.; Tanigaki, N.; Yamamoto, N.; Mizokuro, T.; Hiraga, T.; Tanaka, N.; Nagaeda, H. &

Optical path switching device and method. *US patent*; 7,215,491.

Development of an Optically gated Optical Switch using an Organic Dye - Applied to Local Telecommunication Technology. *Proceedings of SPIE*, Vol. 6891, No.

2011). Switching mechanism of an optically-gated optical switch using an organic

(2007). Optically controlled optical-path-switching apparatus, and method of

(2010). Optically controlled optical-path-switching-type data distribution appratus

A.; Hiraga, T. & Moriya, T. (2003). Coaxial Conguration of the Gating and Signal Light for a Switching Device of a Dye-Dissolved Polymer Film. *Jpn. J. Appl. Phys.,*

Shiga, N. (2010). Optical deflection method and optical deflection apparatus. *US* 

HIMEJI RIKA CO., LTD.. This study is supported by NEDO.

dye. *Proc. of SPIE,* Vol. 7935, No. 79350Y, pp. 1-12.

switching optical paths. *US patent*; 7,301,686.

Vol. 42, No. 3, pp. 1272-1276.

*patent*; 7,826,696B2.

and distribution method. *US patent*; 7,792,398B2.

**4. Acknowledgment** 

**5. References** 

68910G, PP. 1-15.

**7** 

*1,2Australia 3Japan* 

**Optical Demultiplexing Based on Four-Wave** 

**Mixing in Semiconductor Optical Amplifiers** 

*3Graduate School of Materials Science, Nara Institute of Science and Technology,* 

Four-wave mixing (FWM) in semiconductor optical amplifiers (SOAs) has several important features, such as, high speed and high FWM conversion efficiency as well as optical demultiplexing (DEMUX) (Mecozzi *et al.,* 1995; Mecozzi & Mrk, 1997; Das *et al.,* 2000). The are several applications of FWM in SOAs for all-optical devices, such as, wavelength converters (Vahala *et al.,* 1996), optical samplers (Inoue & Kawaguchi*,* 1998), optical phase conjugators (Kikuchi & Matsumura*,* 1998) and optical multiplexers/demultiplexers (Kawanishi *et al.,* 1997; Kawanishi *et al.,* 1994; Morioka *et al.,* 1996; Uchiyama *et al.,* 1998; Tomkos *et al.,* 1999; Kirita *et al.,* 1998; Buxens *et al*., 2000) have been demonstrated for optical communication systems. When a pulse of a time-multiplexed signal train (for example, a probe pulse) and a pump pulse are injected simultaneously into an SOA, gain and refractive index in the SOA are modulated and an FWM signal is generated by the modulations. Thus, we can obtain a demultiplexed signal as an FWM signal at the output of SOA. All-optical demultiplexing has been experimentally demonstrated up to 200 Gbit/s (Morioka *et al.,* 1996). Tomkos *et al.,* (Tomkos *et al.,* 1999) suggested a number of ways to improve the performance of the dual-pump demultiplexer at 40 Gbit/s as follows; adjustment of the input wavelengths at the peak gain wavelength of the SOA under saturation conditions, the use of higher pump power at the input of the device, or/and the use of pulsed pumps with short pulsewidths. For the higher bit-rate, the overlap of the input to the FWM signal pulses may appear both in the time and spectral domain. The pattern effect may also appear in the FWM signal due to the slow components of the optical nonlinearities in SOAs (Saleh & Habbab, 1990). These effects degrade the usefulness of the FWM in SOAs as a practical DEMUX device in optical network/ communication systems. Therefore, it is very important to analysis the optical DEMUX characteristics based on FWM in SOAs for the ultrafast

The analyses of FWM in SOAs between short optical pulses have been widely reported (Shtaif & Eisenstein, 1995; Shtaif *et al.,* 1995; Xie *et al.,* 1999; Tang & Shore, 1998; Tang & Shore, 1999a; Tang & Shore, 1999b; Das *et al.,* 2000). The FWM conversion efficiency (Shtaif *et al.,* 1995; Xie *et al.,* 1999; Tang & Shore, 1998; Tang & Shore, 1999a; Mrk & Mecozzi, 1997)

**1. Introduction** 

multi-bit input optical pulses.

*1Department of Electrical and Computer Engineering, Curtin University,* 

Narottam Das1,2 and Hitoshi Kawaguchi3

*2School of Engineering, Edith Cowan University,* 
