Wideband wavelength tunable lasers are now beginning to play important roles in dense wavelength-division
multiplexing (DWDM) optical transmission systems, because these lasers can reduce the required number of
inventory lasers and inventory costs. They are also key components in the evolution towards future photonic
network systems, particularly in reconfigurable optical add/drop multiplexing (ROADM) systems and optical
cross-connect (OXC) systems. However, before the tunable laser can be a viable alternative for the conventional
fixed wavelength laser (e.g. DFB laser) it should have the same characteristics over its entire tuning range.
Additionally, the device should only be marginally more expensive than its fixed counterpart. This paper reviews
our recent activities on the development of high performance full-band wavelength tunable lasers. Our approach
utilizes an external cavity configuration, which makes use of a liquid crystal (LC) tunable mirror. We
demonstrate high performance of an external cavity wavelength tunable laser (ECTL) with an intracavity etalon.
This ECTL module shows a tuning range of 45 nm, fiber-coupled output power of higher than 14 dBm with
SMSR of better than 59 dB, wavelength accuracy of +/-0.6 GHz, relative intensity noise (RIN) of better than -
150 dB/Hz, and linewidth of narrower than 1 MHz.