Monolithic tunable lasers for low cost DWDM networks

Low-cost tunable lasers are key enablers for next-generation dense wavelength division multiplexing (DWDM) based access and metro networks. At present, tunable lasers are mostly deployed in long-haul optical transmission systems due to their high cost resulting from fabrication and operation complexity for structures such as sampled grating distributed Bragg reflector (SGDBR) [1,2]. For wide deployment of the WDM technology in metro, access, and data center networks, the cost reduction of tunable lasers has become a key issue. Recently, a simple and compact tunable V-cavity laser (VCL) has been proposed and demonstrated [3-4]. By using a specially designed halfwave coupler between two Fabry-Perot lasers, a widely-tunable single-mode laser with high side mode suppression ratio (SMSR) is achieved without requiring complex gratings. Discrete wavelength tuning up to 50 channels at 100 GHz spacing has been demonstrated experimentally with a simple tuning algorithm [5]. Single-electrode controlled fast wavelength tuning in the order of ~10ns has also been achieved by using a quantum well intermixed tuning section [6].