The compact optical channel monitor released by Lightwaves2020 Inc. performs real-time nonintrusive measurement of optical channel power, wavelength and signal-to-noise ratio. Based on proprietary micro-optics and optical thin-film technology, it can scan the C-, L- or C+L bands sequentially and measure/monitor the optical channel power and wavelength at ITU grids of 100 or 50 GHz. Absolute and relative prechannel power accuracy are ±1 and ±0.5 dB, respectively. Absolute wavelength accuracy is ±100 pm. Polarization-dependent loss is 0.3 dB, optical return loss is 45 dB, and maximum adjacent and nonadjacent channel power imbalance are 15 and 20 dB, respectively. The device measures 120 × 92 × 12 mm. Applications include real-time optical performance or channel monitoring of DWDM networks, and erbium-doped fiber amplifier gain balancing.