An apparatus for use in optical communication systems to multiplex/demultiplex an optical signal consisting of an optical channel(s) of distinct wavelength(s) having a select channel spacing within a select wavelength range. The apparatus includes a plurality of optical waveguides aligned generally along the same optical axis with each having a propagating end. At least two of the optical waveguides each propagate a distinct multiplexed optical signal comprising a plurality of channels, with the multiplexed optical waveguides being arranged in a multiplexed linear array. The others of the optical waveguides are single channel waveguides arranged in a two dimensional array with linear rows perpendicular to the multiplex linear array and with each linear row corresponding to a multiplex optical waveguide. A reflective echelle grating is optically coupled to the plurality of optical waveguides along the optical axis and receives an optical signal emitted from at least one of the optical waveguides and detracts the optical signal(s) to at least one other of the optical waveguide(s).