A multi-channel optical transceiver module comprising: a transceiver housing ; a multi-channel transmitter optical subassembly, TOSA , located in the transceiver housing , the TOSA being configured to transmit a wavelength division multiplexed, WDM, optical signal on multiple channel wavelengths, wherein the TOSA includes a thermal arrayed waveguide grating, AWG , for optical multiplexing; and a multi-channel receiver optical subassembly, ROSA , located in the transceiver housing , the ROSA being configured to receive a wavelength division multiplexed, WDM, optical signal on multiple channel wavelengths, wherein the ROSA includes an athermal AWG for optical demultiplexing, a ROSA base portion , wherein the athermal AWG is mounted on the ROSA base portion , and wherein the ROSA is oriented in the transceiver housing with the ROSA base portion facing away from the circuit board and facing a top portion of the transceiver housing such that heat generated by the ROSA is transferred to the top portion of the transceiver housing and dissipated; wherein the TOSA further includes: a laser array configured to generate laser light associated with different respective optical channels, wherein the thermal AWG is optically coupled to the laser array and configured to combine the laser light at different respective channel wavelengths; and a temperature control system configured to control temperature of both the laser array and the thermal AWG with the same temperature control device . a transceiver housing ; a multi-channel transmitter optical subassembly, TOSA , located in the transceiver housing , the TOSA being configured to transmit a wavelength division multiplexed, WDM, optical signal on multiple channel wavelengths, wherein the TOSA includes a thermal arrayed waveguide grating, AWG , for optical multiplexing; and a multi-channel receiver optical subassembly, ROSA , located in the transceiver housing , the ROSA being configured to receive a wavelength division multiplexed, WDM, optical signal on multiple channel wavelengths, wherein the ROSA includes an athermal AWG for optical demultiplexing, a ROSA base portion , wherein the athermal AWG is mounted on the ROSA base portion , and wherein the ROSA is oriented in the transceiver housing with the ROSA base portion facing away from the circuit board and facing a top portion of the transceiver housing such that heat generated by the ROSA is transferred to the top portion of the transceiver housing and dissipated; wherein the TOSA further includes: a laser array configured to generate laser light associated with different respective optical channels, wherein the thermal AWG is optically coupled to the laser array and configured to combine the laser light at different respective channel wavelengths; and a temperature control system configured to control temperature of both the laser array and the thermal AWG with the same temperature control device . a laser array configured to generate laser light associated with different respective optical channels, wherein the thermal AWG is optically coupled to the laser array and configured to combine the laser light at different respective channel wavelengths; and a temperature control system configured to control temperature of both the laser array and the thermal AWG with the same temperature control device . <EOS>