Fig. 2: Broadband wireless–photonic conversion and wireless signal generation.
From: Ultrabroadband on-chip photonics for full-spectrum wireless communications
a, Setup for wireless–photonic conversion. b,c, Measured optical spectra at various wireless (b) and optical (c) carrier frequencies. d, Setup for carrier signal generation based on OEO. e, Working principle of the OEO scheme, in which the oscillation frequency can be reconfigured by tuning the optical resonance frequency, without affecting noise performance. f, Working principle of traditional multiplier-based signal sources, in which the noise cascades. g, Measured OEO spectrum with an RBW of 51 kHz. h, Measured phase noises of OEO signals at various frequencies showing consistent performances across bands. i, Measured frequency error diagram. OSA, optical spectrum analyser; EDFA, erbium-doped fibre amplifier; EA, electrical amplifier; PD, photodetector; MS, microwave source; and c.w., continuous wave.
