  We propose a wavelength-mode sorter realized by multi-plane light conversion
(MPLC). For the first time, to our best knowledge, wavelengths and spatial
modes can be sorted simultaneously. We first demonstrate pure wavelength
sorting by a series of phase masks, which could find applications in high-power
wavelength beam combining (WBC) or coarse wavelength-division multiplexing
(CWDM), for example. We then present a design of a 4-wavelength, 3-mode sorter
using only 5 phase masks. Insertion loss (IL) and mode dependent loss (MDL) as
low as 1.27 dB and 2.45 dB can be achieved, respectively.
