Noise reduction in optical pulses and bit-error-rate improvement with a semiconductor-waveguide saturable absorber

Summary form only given. The technological development of the Er-doped fiber amplifier (EDFA) dramatically changed the scheme of long-haul optical communications. EDFAs have removed electronic 3R (retiming, reshaping, regeneration) function repeaters. However, although the EDFA provides a regeneration function by an optical method, it also causes the accumulation of spontaneous emission noise during transmission and thus induces communication penalty. Therefore, if an optical noise reduction function is realized using a simple optical method, it will bring a great benefit to optical communication systems. In this paper, we report that the optical noise suppression effect is obtained by using a single-chip semiconductor-waveguide saturable-absorber (SWSA). This device can improve the bit error rate in high-speed optical communication. This SWSA has a large advantage for real use in a system because of its simple and compact configuration compared to fiber-based interferometer geometries.