Optical transmitter or transceiver including transmitter optical subassembly (TOSA) modules directly aligned to optical multiplexer inputs

A multi-channel optical transceiver comprising:

• a transceiver housing;
• a plurality of transmitter optical subassembly (TOSA) modules for transmitting a plurality of optical signals at different respective channel wavelengths;
• an optical multiplexer for multiplexing the plurality of optical signals into a multiplexed optical signal including the different channel wavelengths, the optical multiplexer including a plurality of mux input ports optically coupled with and directly aligned to the respective TOSA modules, without using optical fibers, for receiving the respective optical signals and a mux output port for outputting the multiplexed optical signal;
• a multi-channel receiver optical subassembly (ROSA) for receiving a multiplexed optical signal including multiple channel wavelengths, separating the channel wavelengths, and detecting optical signals at each of the channel wavelengths;
• and
• a multiplexer housing receiving the optical multiplexer, the multiplexer housing including at least one side wall with input apertures aligned with the mux input ports, wherein the TOSA modules are mounted to the sidewall.