Abstract: The specification describes stepped etalon structures and techniques for their fabrication. The preferred etalon material is LiCaAlF6, which is not efficiently processed using reactive ion etching. The approach of the invention is to produce the steps on the etalon by depositing a blanket layer of step material that is effectively etched by RIE, masking a portion of the step material, and etching the masked blanket layer using the LiCaAlF6 substrate as an etch stop. These process steps may be repeated to form multiple steps on the etalon. Etalon structures with steps on both major surfaces are described, as well as etalon structures with steps having differing areas. In the latter case a difference in amplitude in the output signal from a single detector can be used to identify the step that is resonating.

Abstract: A method and apparatus for stabilizing the wavelength of a laser are disclosed. The invention provides a way to stabilize a laser for applications in dense wavelength division multiplexing (DWDM) systems where frequency spacing is crucial. The invention accomplishes laser stabilization by generating an optical path which is passed through a filter to obtain a signal which is a function of frequency. A second optical path which does not contain a filter is generated to obtain a signal which is a function of power. The signals are then converted from optical to electrical and from analog to digital, and a microcontroller is used to normalize the frequency path with respect to the optical power path, process the signals via software code, and generate a signal which provides feedback to the laser for stabilization.

Abstract: An apparatus for stabilizing the wavelength of light emitted by a laser or light source comprising a divider for dividing a sample of emitted light into a first and second portion; a first photodetector configured to measure an intensity of the first portion and a second photodetector configured to measure an intensity of the second portion, the second photodetector configured to receive the emitted light via an optical frequency discriminator, such as a dielectric coating, wherein the optical frequency discriminator is configured to modify the intensity of the emitted light at the second photodetector as a function of an optical frequency of the emitted light; and a processor configured to maintain a desired level corresponding to a ratio of the intensity measured by the first photodetector and the intensity measured by the second photodetector, so as to provide a feedback control signal to adjust the wavelength of the emitted light.

Abstract: In practical WDM systems, the maximum SMSR for each channel does not necessarily occur where dP.sub.out /dI.sub.tune =0. In fact, for most channels the maximum SMSR occurs at values of tuning current where this first derivative in not zero. In accordance with one aspect of the invention, a wavelength stabilized optical transmitter includes a DBR laser and a feedback loop for controlling the center wavelength of the laser, characterized in that the transmitter also includes a memory in which are stored the non-zero values of dP.sub.out /dI.sub.tune where the SMSR is a maximum for each of a multiplicity of different channel wavelengths and further includes a controller responsive to the stored values for delivering to the laser a level of tuning current that maximizes the SMSR for a particular channel wavelength.

Abstract: In accordance with the present invention, a wavelength selectable laser source comprises a tunable pump source, an array of waveguide lasers for emitting light at respectively different wavelengths and a router for directing light from the pump source to an appropriate waveguide laser. A second router can be used to direct all laser outputs to a common output waveguide. The result is a wavelength selectable, stable signal source. In preferred embodiments the routers are dense wavelength-division multiplexers (DWDMs) and the waveguide lasers are rare-earth doped fiber lasers. Alternative embodiments provide a variety of ways of routing the pumping source.