Abstract

Frequency Division Multiplexing (FDM) techniques are expected to play an important role in future optical broadband communication systems.¹ Good selectivity can be obtained in high- density FDM systems with heterodyne receiver configurations, and the use of optical amplifiers allows one to compensate for system losses. However, in heterodyne systems with optical amplifiers, the Local Oscillator-spontaneous emission (LO-sp) beat noise may limit the number of channels, particularly at high bit rates. The introduction of an Image Rejection Receiver (IRR) configuration will halve the LO-sp beat noise^2,3 thereby doubling the dynamic range and thus doubling the number of channels which can be transmitted. The experimental verification of the reduction of LO-sp beat noise is demonstrated with a simple, all-fiber Optical Image Rejection Mixer (OIRM).⁴

© 1991 Optical Society of America