Micromachined Laser Offers Tunability

Richard Gaughan

In the hope of adding flexibility to optical communications networks, researchers at Nanyang Technological University have micromachined an external-cavity Fabry-Perot laser diode that is wavelength-tunable.

In the May issue of IEEE Photonics Technology Letters, the researchers describe the design of the 2 x 1.5-mm package, which incorporates a movable micromirror. The mirror was produced by three-layer-polysilicon micromachining processes and was manually lifted to its final vertical configuration onto a movable stage.

A control voltage changes the position of the 300 x 300-µm mirror with respect to the laser diode. With an added drive voltage of ±3 V, the wavelength of the laser diode varies from 1528 to 1544 nm, stepping through different single modes. An optical fiber is bonded to the substrate about 15 µm from the exit face of the diode.

The device could be used in wavelength division multiplexing, making it easy to switch from one channel to another and allowing rapid remote reconfiguration.