2-cm-long sinc-sampled gratings with Bragg wavelengths of 1550 nm comprising 4-, 8-, and 16 wavelength channels, respectively. Reflection is completely suppressed out of the reflection band. For a given N c , the reflectivity of all channels is uniform. The reflectivity is decreased from 1 to 0.974 and linewidth is decreased from 237 pm to 56 pm when the number of channels is increased from 4 to 16 and the other grating parameters remain unchanged. Figure 7 re-shows the 8-channel reflection spectrum within the wavelength region from 1548 nm to 1552 nm. All channels exhibit identical characteristics of both reflectivity and channel separation. With the length of the grating increased, the flat-top region is broadened. The higher the number of channels required, the larger the refractive index change needs to be designed, in order to implement high reflectivity. These sampled gratings have been demonstrated experimentally by Ibsen [7], and our simulation results coincide well with those experimental results. In addition to their perfect filter properties, the comb filters based on sincsampled gratings are easier to fabricate to specification, less expensive to manufacture, and more stable when packaged. Therefore, we may predict this comb filter will be an effective device applied in the WDM systems. 5. CONCLUSION 2. K.P. Koo and A.D. Kersey, Bragg grating-based laser sensors systems with interferometric interrogation and wavelength division multiplexing, , 30 dB sampled gratings in germanosilicate planar waveguides, Electron Lett 32 (1996), 2233-2235. 5. M. Yamada and K. Sakuda, Analysis of almost-periodic distributed feedback slap waveguides via fundamental matrix approach, Appl Opt 26 (1987), 3474 -3478. 6. M. Ibsen, M.K. Durkin, M.J. Cole, and R.I. Laming, Sinc-sampled fiber Bragg gratings for identical multiple wavelength operation, IEEE Photon Technol Lett 10 (1998), 842-844. ABSTRACT: A planar circuit realization of a frequency discriminator based on single-mode operation of the dielectric resonator is presented. Drawing on the phase-shifting action of the dielectric resonator, the discriminator function can be achieved with one detector diode, thus adding to the simplicity of the design. It is demonstrated with measurements on the performance of discriminators implemented with dielectric resonators having different temperature coefficients that effective frequency stabilization by thermal compensation for the substrate material can be facilitated by the additional degree of freedom brought about by the dielectric resonator. ABSTRACT: Injection locking of an erbium-doped fiber laser-amplifier is presented. Inside the locking range, the system oscillates at the wavelength of the injected signal. Outside the locking range, both signal and laser oscillate simultaneously in the cavity. Signal detuning studies show that the locking range increases with higher input signal power.
