Abstract

Interconnection of local area networks (LANs) based on wavelength-division multiplexing, with the same set of frequencies used in each LAN, can provide a means for achieving large, high-bit-rate optical networks.¹ Routing between LANs can be accomplished by reassigning one of the wavelengths by using a wavelength shifter. This wavelength shifter needed for frequency-reuse applications must be broadband around 1.5 μm, able to operate at high bit rates, and cascadable with negligible signal degradation.² Data transfer at bit rates of 1 or 2 Gbit/s has been demonstrated by using two cascaded semiconductor amplifiers under gain saturation.³ In this experiment the carrier-depletion effect in a three-section distributed-Bragg-reflector (DBR) laser⁴ is used for the first conversion and the injection-locking principle in a distributed-feedback (DFB) laser is used for the second conversion.⁵ By this dual conversion, signal polarity and a 12-dB extinction ratio are preserved. Furthermore, the critical wavelength adjustment for injection-locking conditions is strictly independent of the input and output wavelengths.

© 1995 Optical Society of America