A true time delay beamforming system incorporating a wavelength tunable optical phase-lock loop

作者：Rideout Howard R^*; Seregelyi Joe S; Yao Jianping

来源：Journal of Lightwave Technology, 2007, 25(7): 1761-1770.

DOI：10.1109/JLT.2007.899189

• beamforming
• external cavity laser (ECL)
• fiber Bragg grating (FBG)
• microwave photonics
• optical delay line
• optical heterodyne
• optical phase-lock loop (OPLL)
• phased-array antenna (PAA)
• true time delay (TTD)

A true time delay (TTD) beamforming system incorporating a wavelength tunable optical phase-lock loop (OPLL) module is proposed and experimentally demonstrated. In the proposed system, instead of using a high-frequency intensity modulator to modulate the optical carrier with an RF signal, we use two laser diodes (LDs) that are phase locked to generate an RF signal, which is then sent to a fiber Bragg grating (FBG) prism to produce different time delays. Since no optical intensity modulator is used, the system can operate at much higher frequencies with a reduced cost. In addition, the use of only two wavelengths eliminates the power-penalty problem caused by chromatic dispersion. In the proposed approach, the wavelengths from the two LDs are phase-locked using a frequency-discriminator-aided OPLL. A TTD beamforming system, using the OPLL in combination with an FBG prism to achieve tunable time delays, is investigated. Experimental time-delay results are provided.

• 出版日期2007-7