A tunable triple-channel-wavelength fiber laser based on a
digital-micromirror-device (DMD) is demonstrated. The DMD processor is controlled
by a FPGA system to load grating image to the device storage, and the device driver
switches the pixels array to generate reconfigurable reflective digital diffraction
gratings on DMD surface. When light irradiates on DMD, corresponding wavelengths
are selected and sent to erbium-doped fiber amplifier (EDFA). Hence, a
multiple-wavelength laser is generated with laser line - width of 0.02nm. The tunning
is fine enough to cover the C-band with a step of 0.08nm and the side mode
suppression ratio (SMSR) is larger than 50 dB at room temperature. The switching
speed of DMD to generate new gratings on the array is as fast as 1.92 ms.
A variety of traffics from different communications networks have been demonstrated to show the self-similarity. A novel method to estimate the degree of self-similarity based on the index of dispersion for counts, a second-order statistic, is proposed in this paper. Its principle is introduced in brief and validation is made in detail on the basis of two self-similar process models, Sup_FRP and FBNDP. Qualification and comparison show that the method possesses simpler algorithm than the wavelet-based estimator and that it exhibits higher accuracy and reliability than the R/S estimator and the Variance-time analysis.