Polarization Independent Semiconductor Optical Amplifier Gate and Its Application in WDM Systems

Toshio ITO  Naoto YOSHIMOTO  Osamu MITOMI  Katsuaki MAGARI  Ikuo OGAWA  Fumihiro EBISAWA  Yasufumi YAMADA  Yuji HASUMI  

IEICE TRANSACTIONS on Electronics   Vol.E81-C    No.8    pp.1237-1244
Publication Date: 1998/08/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on High-Capacity WDM/TDM Networks)
semiconductor optical amplifier,  gate array,  spot-size converter,  polarization independence,  wavelength selector,  

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We studied 2 types of polarization insensitive semiconductor optical amplifier (SOA) gates for use in wavelength division multiplexing (WDM) applications: 1) a low operation current SOA gate with a small and square bulk active region but without spot-size converters and 2) a multi channel SOA gate array with tapered waveguide spot-size converters (SS-SOA) on both sides. The low operation current SOA gate provided a very low current for fiber-to-fiber loss-less operation (5. 4-7. 0 mA) and a high extinction ratio (>30 dB) over a wide wavelength range (1530-1580 nm). For multi channel array assembling, the SS is indispensable. The 4-channel SS-SOA gate array was assembled on a planar lightwave circuit (PLC) platform for the first time. The gain characteristics of each channel were very similar and a low fiber-to-fiber loss-less current of 33 mA and a high extinction ratio of nearly 40 dB were achieved in all channels. The polarization dependence was less than 1 dB. Using the fully packaged 4-channel hybrid gate array module (a 4 channel SS-SOA on PLC platform), an ultra-wide-band (1530-1600 nm) high speed wavelength selector was successfully demonstrated. Both rise- and fall-times were less than 1 ns, which makes the wavelength selector suitable for high-speed optical packet switching. Electrical and optical interference between channels were negligible.