An optical assembly includes a first transparent substrate having first and second surfaces, a second transparent substrate having substantially parallel third and fourth surfaces, a reflective portion on the second transparent substrate, a plurality of filters between the first substrate and the reflective portion, the plurality of filters filtering light beams incident thereon, the plurality of filters and the reflective portion forming a bounce cavity within the second transparent substrate, a collimating lens for collimating light beams to be input to the bounce cavity, a tilt mechanism for introducing tilt to light beams input to the bounce cavity; an input port receiving light beams and an output port transmitting light beams. The tilt mechanism may be between the first and second substrate.