Q: What will the microQSFP (Micro Quad Small-Form-Factor Pluggable) MSA address and the microQSFP specification define? (Optical interfaces and copper?)
A: The microQSFP MSA will develop a specification for a new compact module form factor, microQSFP, and make the specification available to the industry to promote industry adoption of compatible products that can be used for a variety of applications including copper cable and fiber-optics transceivers in a manner similar to SFP or QSFP form factors. There will be sufficient details in the specification such that the components of the form factor (host board electrical edge connector, cage and plug with latching mechanism, where the plug can be a cable termination or transceiver) are mechanically and electrically interchangeable if compliant to the specification.
The microQSFP specification is expected to be applied to direct attach cables (DACs), active optical cables (AOCs), and connectorized optical modules to enable higher port density. The microQSFP module’s compact design will be well suited for a wide range of applications within the data center accommodating copper, VCSEL (vertical cavity surface emitting laser), SM (single mode) laser or Silicon Photonics (SiP) based technology.
Q: Aren’t smaller modules limited by thermal constraints?
A: microQSFP modules will have enhanced thermal management capabilities and therefore will be well suited for higher power applications that extend links outside of the data center. Initially, microQSFP modules will support links similar to SFP and QSFP and as technology improves and the relative power decreases, longer reach applications up to 100’s of km may be possible.
Q: Is this a form factor for client-side interfaces or line-side (long distance) interfaces?
A: The microQSFP MSA specification will define a high-density, pluggable, 4-channel form factor that supports signaling up to 28 GBaud and beyond. Either direct attach cables or optical transceivers can be implemented. Given the high-density of the microQSFP module, it is less likely to be used for long-haul line-side applications although it may happen with time. The most likely applications will be client-side interfaces inside the data center that support up to 10 km on SMF (single mode fiber) and 100 meters on MMF (multi-mode fiber).
Q: How does the port density of microQSFP compare with present 4x28G QSFP or 1x28G SFP density?
A: The microQSFP form factor will be approximately the same width as the SFP form factor, but the electrical connector will provide four electrical channels like the QSFP form factor. In a two row implementation, the microQSFP will fit at least 48 ports on a line card and, in a three row implementation, at least 72 ports can be accommodated. When each lane is used as an independent channel, it allows microQSFP to offer 4x the port density of SFP and, when used in an aggregated lane mode, to offer 1.5x the port density of QSFP.