Broadband Brillouin-based phase shifter with phase amplification in a silicon waveguide

Chip-Based Brillouin Processing for Microwave Photonic Phased Array Antennas

“…Fig. 12 (b) shows the un-enhanced ±7.3°phase shift over the RF frequency range 5-20 GHz generated from 2 dB of Brillouin gain using suspended silicon waveguides [75]. When the phase is amplified by the interferometric phase enhancement technique, a 360°phase shift is achieved using an enhancement factor of 25, as shown in Fig.…”

“…One challenge faced by forward Brillouin devices is that the strong co-propagating pump must be filtered to avoid the generation of spurious terms caused by beating between the pump and probe at the PD [75]. The photonic-phononic emitter-receiver (PPER) structure demonstrated by Shin et al [66] shown in Fig.…”

“…11 (c), while keeping RF power fluctuations within only ± 1.5 dB. Although good performance was demonstrated, achieving 360°phase tunability, which is required for beam steering in PAAs, demands more than 50 dB of Brillouin gain, leading to excessively large optical pump power [75].…”

“…When RF 1 and RF 2 are added, the overall phase shift, Θ 2 , is larger than the optical phase shift, Θ 1 , applied to RF 1 , at the expense of a reduced RF link gain [78]. The phase enhancement factor is defined as the ratio of the enhanced phase shift to the raw phase shift [75].…”