Optimal design of a multimode interference (MMI) coupler for broadening the spectral response of an arrayed-waveguide grating (AWG) demultiplexer is considered. By using a Gaussian beam approximation, an analytical expression for the spectral response of an AWG demultiplexer (with an MMI section) is obtained. A simple analytical formula is derived to relate the optimal MMI length to the separation between the peaks of the twofold images in the MMI region. This peak separation is related to the width of the MMI section. In the proposed design method, a required 1-dB passband width determines the peak separation, which then determines the optimal value for the length of the MMI section according to the analytical formula. The designed flat-top AWG demultiplexer is verified by the beam propagation method.


PDF Article

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
Login to access Optica Member Subscription