Tunable Multiwavelength Fiber Laser Source for Continuous True-Time-Delay Beamforming

We present a novel approach of a true-time-delay (TTD) laser source for continuous phased-array beamforming employing a semiconductor optical amplifier (SOA) and a tunable Fabry–Perot filter (FPF). The wavelength tuning is achieved by tuning the cavity length of the filter, to which an SOA that generates the
$C$
-band optical signal is applied. A five-channel TTD system based on a linear chirped fiber grating (LCFG) has been constructed and experimented using the proposed laser source. The signal-to-noise ratio of the obtained multiwavelength signal can be more than 35 dB. Thanks to the high position resolution of the translation stage, the time delay responses can be continuously controlled by changing the cavity length of the FPF.