A novel diagnostic system for inspection of fiber-optic cables

In this proposal, we outline a novel Pseudo Random Binary Sequence (PRBS) approach for low cost, non-intrusive inspection of fiber optic cables. The approach incorporates non-complex mixed signal electronic and photonic components that can easily be implemented as an ASIC to achieve compactness and allow easy integration with a fiber-optic cable system. This approach has already been tested at IAI by developing compact hardware as a part of a project funded by the FAA. The basic principle underlying the approach is the cross correlation property of a PRBS injected into a fiber-optic cable with the ensued reflection due to a cut defect or the end of the cable. The correlation of the exact input with the return signal gives the impulse response of the circuit (cable). This impulse response completely characterizes the transfer function of the cable. The electronic and photonic components required to implement our approach are already available commercially. Our approach does not require any high speed digitization and solves the resolution and dead zone problem associated with OTDR methods. During Phase I, we will develop a stand-alone system for inspection of fiber-optic cables. We will also develop a system diagram for an ASIC implementation during Phase II.