LASER TUNERS AND WAVELENGTH-SENSITIVE DETECTORS BASED ON ABSORBERS IN STANDING WAVES

We propose a new method for making laser tuners and wavelength-sensitive or tunable detectors that is based on absorbers in standing waves. Because the method does not rely on mechanical movement or changes in refractive index, it may offer high-speed tunable devices whose range is not constrained by limits on the size of refractive index changes. The devices can be made either in a longitudinal form by back reflection, or in a transverse form by interfering beams at an angle on a surface. We give theoretical models for these structures, and illustrate the concepts with various specific device designs. These include a narrow band detector based on transverse gratings, a simple wavelength sensitive longitudinal structure with a single absorber, and a two-absorber longitudinal structure capable of many functions, including a narrow band detector, a two-wavelength detector, a wavelength measuring detector, a continuously variable laser tuner, and a laser phase controller. These devices can all be made using layered semiconductor growth and lithography, and are particularly suited to quantum wells. The devices are applicable to wavelength division multiplexing and switching, and to sensors and spectroscopy.