This 47-page white paper from the Consortium for On-board Optics (COBO) describes configuration options for switch components utilizing on-board optics or co-packaged optics. The paper, which represents the work of 56 companies over 2 years review design options available to accommodate compact MDIs and external laser sources, considering their impact on optical signal, thermal, and safety criteria.
Download here (no registration required)
https://www.onboardoptics.org/_files/ugd/8abe6c_8b419af450954e9b932845335adefdba.pdf