Fiber grating based optical recirculating filter with an optimized response

A novel optical recirculating filter for RF applications is described, whic h exploits a specially designed fiber grating with a ramped spectral profil e to enable optimization of the filter response. The design overcomes the l imitations impose by loss in conventional fiber recirculating filters. Addi tionally, a tunable free spectral range is demonstrated by using the device in a grating array. Both theoretical and experimental results are presente d and discussed.