[1] [1] Pan Z, Yu C, Willner A E. Optical performance monitoring for the next generation optical communication networks. Optical Fiber Technology, 2010, 16(1): 20–45

[2] [2] Suzuki H, Takachio N. Optical signal quality monitor built into WDM linear repeaters using semiconductor arrayed waveguide grating filter monolithically integrated with eight photodiodes. Electronics Letters, 1999, 35(10): 836–837

[3] [3] Lee J H, Jung D K, Kim C H, Chung Y C. OSNR monitoring technique using polarization-nulling method. IEEE Photonics Technology Letters, 2001, 13(1): 88–90

[4] [4] Chan C C K. Optical Performance Monitoring: Advanced Techniques for Next-Generation Photonic Networks. Amsterdam: Academic Press, 2010

[5] [5] Wang D, Cao J, Peng Y, Ma H, Fu H, Geng D, Li J, Li Z. OSNR monitoring based on low-cost coherent scanning receiver and reference spectrum technique. In: Proceedings of Asia Communications and Photonics Conference (ACP). 2014, ATh4G.3

[6] [6] Do C C, Zhu C, Tran A V. Data aided OSNR estimation using lowbandwidth coherent receivers. IEEE Photonics Technology Letters, 2001, 26(12): 1291–1294

[7] [7] Lin H, Gui T, Li J, Ma H, Fu F, Geng D, Li Z. Optical power monitoring based on low-cost coherent scanning technique. In: Proceedings of International Photonics and Opto-Electronics Meetings (POEM). 2014, FTh3F.2