Embodiments described herein include a multichannel transmitter optical subassembly that includes a plurality of lasers and a signal combiner. The plurality of lasers may be configured to emit light each with a different one of a plurality of light signals, each of the plurality of light signals having a wavelength within one of a plurality of wavelength bands. The signal combiner may be disposed relative to the plurality of lasers to receive the plurality of light signals. The signal combiner may include at least one surface having an optical coating that reflects at least one of the light signals of the plurality of light signals and transmits at least one of the light signals of the plurality of light signals.