Amusingly the lenses are worse than silicon at transmitting that wavelength.

1550nm might be worse for sensors because a good portion of the light is only being dumped into the metal layers - pure silicon is mostly transparent to 1550nm. Not sure how doped silicon would work. I can tell you that 1070nm barely works on an IQ3 Achromatic back…

https://www.pmoptics.com/silicon.html