Kazutaka Nara, Junichi Hasegawa and Toshiaki Tsuda
With the rapid spread of FTTH services in recent years, there have been proposals for a broadband passive optical network (B-PON) system that combines data transmission services with simultaneous video distribution services. Taking advantage of the new wavelength assignments - 1.31, 1.49 and 1.55 µm - which have become international standards under ITU-T G983.3, requires a WDM filter that is economical and of high functionality to multiplex these three wavelengths. Specifically, central offices require compact WDM modules that contain WDM filter arrays.
Accordingly we have developed an 8-channel 3-wavelenth wideband WDM filter array using a new optical circuit configuration based on a Mach-Zehnder interferometer (MZI) that uses silica-based planar lightwave circuit (PLC) technology, and have been able to obtain good performance: insertion loss of <1.96 dB, loss ripple of <0.77 dB and isolation of >32 dB.