An optical coupler operates as a reflective splitter for predetermined wavelengths and operates as an optical transmissive combiner and an optical transmissive splitter for other wavelengths. Wavelength-selective reflective elements reflect the predetermined wavelength from an output of a transmissive coupling element and pass other wavelengths to another the transmissive coupling element. The optical coupler also includes wavelength-selective coupling elements to transfer the predetermined wavelength between outputs of transmissive coupling elements and inhibit transmission of other wavelengths therebetween. The wavelength-selective coupling elements can be long-period gratings with a resonance wavelength at the predetermined wavelength. The wavelength-selective reflective elements can be Bragg gratings with a grating spacing of one-half the predetermined wavelength.