| 摘要 |
It is found that the use of a multimode interference (MMI) section (22,33,36) to flatten the pass-bands of an arrayed waveguide grating (AWG) multiplexer/demultiplexer or comb filter device introduces undesirable wavelength dispersion into those pass-bands if that MMI section mixes modes of more than two different orders, and if the grating of that device is a 'uniform' grating whose waveguides are equally (minimally) attenuating, and in which the optical path length difference between each adjacent pair of waveguides (40) of the array is the same. This dispersion can be substantially compensated by appropriate 'tailoring' of the grating's path lengths and attenuations (39) to remove such uniformity. <IMAGE> |
