Approaching capacity limits in photon-starved noisy optical communication

Abstract

We show that utilizing pulse position modulation and photon number resolving detectors together with techniques such as quantum pulse gating allows to approach ultimate quantum limit on optical communication capacity in the presence of background noise in the weak output power regime. This shows that for communication over long distances by means of current existing technology it is possible to attain optimal performance, limited only by laws of quantum mechanics.

Photon information efficiency limits in deep-space optical communications

“…An advanced mathematical analysis of the PIE limit shows that for a given noise strength n n , the GH PIE limit is indeed saturated for unrestricted bandwidth, when n s → 0. 18,19 However, one should note that convergence is exceedingly slow and requires even higher PPM orders than those indicated previously, as seen in Fig. 6(f).…”

“…Reaching high PIE values requires a scalable modulation format that can be implemented at high orders. In the case of PPM, communication with frames of length up to 2 15 slots has been demonstrated in laboratory settings, 38 and very recently the PPM order 2 19 has been used to achieve the PIE of 12.5 bits per photon with independent free-running clocks at the transmitter and the receiver. 39 Generation of a high-order PPM signal for photon-efficient communication poses a number of technical challenges, such as managing high peak-to-average power ratio, and ensuring a sufficiently good extinction ratio so that empty slots do not carry any residual optical radiation.…”