Laser-diode phase-shifting interferometer applied to a joint-transform correlator

摘要

A phase-shifting interferometer with a laser diode (LD) has been applied to a joint-transform correlator. An LD six-stepping interferometer is insensitive to the changes in laser power associated with the current variation. A new method producing a joint-transform phase correlator (JTPC) is presented in which the phase in a joint-power spectrum (JPS) of two inputs is measured by the technique of LD phase-shifting interferometry. A charge-coupled device records the JPS those recording optical layout is an on-axis type by using a Mach-Zehnder interferometer. A single centered correlation is generated by the numerical Fourier transformation of the measured phase. A JTPC exhibits sharper correlation peak than the conventional JTC. The experimental results with a JTPC are shown.