As bandwidth increases in communication networks, more DWDM (dense wavelength-division-multiplexing) systems are being deployed which provide high-capacity transmission of multiple signals over single optical fibers. The need for real-time monitoring of every optical channel is critical to ensure quality of network (QON). Thousands of InGaAs linear photodiode arrays are deployed in optical communications networks globally. They serve as the detector unit in an integrated spectrometer device (optical channel performance monitor, or OCPM) which rapidly monitors performance of all channels as well as providing optical signal to noise ratio (OSNR) and power measurements.

An OCPM monitoring channel intensity, power, and signal-to-noise ratio.