A transceiver separates wavelength-division-multiplexing (WDM) components into two groups, one of which is more sensitive to temperature than the other group. The temperature-sensitive group of optical components is implemented on a first substrate in the transceiver that has a lower thermo-optic coefficient than a second substrate in the transceiver, which contains the group of optical components that is less temperature sensitive. In particular, the first substrate, which may be glass, may include WDM components that convey optical signals having multiple carrier wavelengths. Moreover, the second substrate, such as a silicon substrate (e.g., a silicon-on-insulator platform), may include multiple parallel optical paths with optical components, in which a given optical path conveys an optical signal having a given carrier wavelength.