What does this equation mean?

Anchoring at $R_0$ = 200 Gb/s per lane, $t_0$ = 2026 , and holding the most recently observed four-year doubling period fixed gives R(2035) = 200 $\cdot$ 2^{9/4} $\approx$ 950 Gb/s per lane by 2035 — essentially a 1 Tb/s single electrical lane. That number is offered to be doubted, not believed. The assumption it encodes — that the doubling period keeps compressing on a fixed clock rather than lengthening as channel loss and signal-to-noise margin close in — is exactly the part the standards process itself is already hedging against: P802.3dj did not simply push PAM-4 harder, it added an 800 Gb/s coherent-signalling option specifically for the reaches where intensity-modulated PAM-4 stops being the cheapest way to add bandwidth [ 5 ] . That is a documented fact about how the last doubling was actually achieved — partly through a different modulation scheme, not only through a faster clock — and it is a reason to expect the next doubling to arrive through some mixture of higher-order modulation, coherent optics, and more parallel lanes rather than through PAM-4 alone continuing to double on schedule.