Simultaneous Optical Signal Sampling for Orthogonal Components of Optical Phase Shift Keying Signals with Bidirectional Use of a Chirped Periodically Poled LiNbO₃ Wavelength Converter

Abstract

All optical signal sampling technique with bidirectional use of a periodically poled LiNbO₃ (PPLN) wavelength converter is proposed. An optical phase shift keying (OPSK) signal is divided and injected to the each end of the PPLN together to sampling pulses adjusted to 0 or π/2 phase. Orthogonal components of the OPSK signal are output from the each port of the PPLN simultaneously through difference frequency generation of both directions in the PPLN. Effectiveness of the proposed scheme is confirmed by an experiment of describing a constellation of an optical quadrature phase shift keying (QPSK) signal.