GENERALIZED RESONANT COUPLER FILTERS

摘要

A signal processing circuit, the signal processing circuit comprising firstandsecond waveguides, a series of successive couplers C i between the first andsecondwaveguides, the couplers being spaced from each other along the first andsecondwaveguides, the first and second waveguides having a delay differential.DELTA.L k betweensuccessive couplers Ck-1 and C k, the delay differentials .DELTA.L k not beingall the same.The first and second waveguides preferably have delay differentials betweensuccessivedirectional couplers defined by.beta..DELTA.L k = .beta.n k .DELTA.L+.PHI.kwhere n k is a set of co-prime positive integers, .beta. is defined by.beta.=2.pi.n eff/.lambda., .DELTA.L is definedby .DELTA.L=c/n eff .DELTA.f, c is the speed of light in a vacuum, n eff isthe effective refractive indexof the conduit, .lambda. is a wavelength selected from a range of carrierwavelengths .lambda.1.....lambda.NCh for which the add/drop multiplexes is resonant, .PHI.k is aphase parameterbetween 0 and 2.pi., and .DELTA.f is a pre-selected spectral range of theresonant coupler.