An Integrated Module with a 1.5 um Waveguide Laser and a Multi-Gigahertz Modulator in LiNb03

The major hindrance in the way of integration of a laser source and an external modulator in ferroelectrics has for long been the lack of efficient waveguide lasers and amplifers suitable for integration in these materials. However, with the recent resurgence of interest in rare-earth doped, waveguide lasers in LiNbO3 and in view of the promising results already achieved, the on-chip integration of the waveguide laser and modulator appears to be quite attractive as an alternative to their integrated counterparts in semiconductors. We propose to develop an integrated laser/modulator module capable of delivering optical radiation in the spectral region around 1.55 um and modulated by microwaves with frequencies in the multigigahertz range. The two building blocks of the module are high-relectance Si grating for the CW laser and high-speed traveling-wave modulators with domain-reversals to provide AM modulation at frequencies of tens of gigahertz. High-speed bandpass modulators have already been experimentally realized at Advanced Photonics Technology (APT). The technology of high reflectance grating has originally been developed in the Photonics Research Laboratory (PRL) at the University of Florida and is currently being transferred f rom PRL to APT. These gratings provide th necessary laser feedback without requiring relecting endfaces and hence, are perfectly suited for integration. In Phase I of the proposed effort, a phototype of an Er-doped waveguide laser in LiNbO3 should be developed with the intent of its further implementation in the complete integrated multi-gigabit source/modulator module for advanced photonics systems.