ABSTRACT
Tunable lasers are natural complementary components in optical switches of various kinds. They generally are used for the function of wavelength switching or “wavelength conversion,” in which an incoming signal on one wavelength is remodulated onto another wavelength on the output. Some tunable embodiments appear to have reached specification parity with distributed-feedback (DFB), so the situation may indeed be favorable for tunables in future wavelength division multiplexing (WDM) networks. Work at UCSB and Agility Communications has aimed to develop widely tunable lasers and transmitters with monolithically integrated modulators. The control of multi element tunable lasers has been a roadblock to their general acceptance for some time. Most system engineers are accustomed to incorporating a two-terminal device, such as a DFB laser, in their optical transmitters. Of course, even for the DFB the device temperature is used to fine tune and lock the wavelength in WDM systems.
