Method and circuit for demultiplexing an optical signal

摘要

A system and method are disclosed for demulitplexing closely spaced channels carrying optically encoded data. A composite optical signal having data channels corresponding to center wavelengths lambda 1, lambda 2, lambda 3, lambda 4, . . . lambda n are separated into two composite optical signals of first of which comprises data channels corresponding to center wavelengths lambda 1, lambda 3, . . . lambda n and a second which comprises data channels corresponding to center wavelengths lambda 2, lambda 4, . . . lambda n-1, wherein adjacent channels center wavelengths are separated from one another by a distance "d". A periodic multi-cavity Fabry-Per+E,cir o+EE t etalon having a free spectral range of "2d" is coupled to a circulator for launching an input beam. The first of the two composite optical signals carrying channels 1, 3, . . . n is reflected from the input port of the etalon and the second of the of the two optical signals carrying channels 2, 4, . . . n-1 is transmitted through the etalon. After the two signals are separated, further separation can be achieved by using conventional dichroic filters.