Donald A. Powell

Dynamic optical filtering in DWDM systems using the DMD

Summary form only given. We describe applications of the Texas Instruments Digital Micromirror Device (DMD) as a high efficiency spatial light modulator for dynamic optical filtering and switching in Dense Wavelength Division Multiplexed (DWDM) optical networks. Whereas the DMD has found wide acceptance as a spatial light modulator in video display applications, the present paper describes applications of the DMD to DWDM signal processing. The DMD is shown in this work to behave as a 2-dimensional switched blazed gating when modulating coherent light. In addition, the efficiency of fiber coupling will be shown to depend on the amplitude of the overlap integral between the modulated field and the mode of the output. Hence, the efficiency of the fiber coupling depends not only on the amplitude of the fields, but on how well they are matched in phase. The DMD is very suitable to digital processing of optical networking signals where it can be used as a series of parallel optical switches (e.g. 400-l/spl times/2 switches). A very useful optical platform combines the DMD with a dispersive element such as a gating or a prism. DWDM signals are first dispersed and impinge onto the DMD, which is then used as a reflective adaptive slit. The DMD selectively routes specific wavelengths back into one of two optical paths or ports. Using this general configuration of the DMD as an adaptive optical slit, we have demonstrated several network functions including digital optical equalization, optical add drop multiplexing and optical performance monitoring. In this presentation, we will describe these applications of the DMD as well as describe system performance attributes (insertion loss, polarization dependent loss, group delay and power penalty) as they pertain to the DMD structure and DMD based optical signal processing.

DLP™ switched blaze grating; the heart of optical signal processing

We have developed an approach for processing communication signals in the optical domain using a DLP digital mirror array driven by a Digital Signal Processor (DSP). In optical communication systems, modulation rates of 10 GB/s and above are common, hence, direct processing of Dense Wavelength Division Multiplexed (DWDM) optical signals without undergoing Optical to Electrical conversion has become a key requirement for cost effective deployment of dynamic optical networks. This work will discuss primarily applications of Optical Signal Processing (OSP) to coherent DWDM signals. Optical Signal Processing has also found applications in spectroscopy, microscopy, sensing, optical correlation, and testing.