Enhanced wavelength tuning in grating-assisted codirectional coupler filter

Wavelength-tunable devices based on grating-assisted codirectional coupler filters have been shown to possess enhanced wavelength tunabilities and are promising for use in multiwavelength communication networks. It was found theoretically that the enhancement factor can be estimated by the mismatch of group velocities between the two coupled models. We have confirmed this prediction via measurements of wavelength tuning for both the coupler filter and the Fabry-Perot filter in reverse bias. These measurements are accomplished with photonic-integrated devices. An enhancement factor of approximately 11 is measured on our device, which agrees very well with the theory.<
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