A novel photonic approach to generating a frequency-quadrupled millimeter-wave (mm-wave) signal with a tunable phase shift is proposed and demonstrated. Two second-order optical sidebands are generated by using a Mach-Zehnder modulator (MZM) that is biased at the maximum transmission point and an optical notch filter. A polarization-maintaining fiber Bragg grating (PM-FBG) is then uti... https://www.parisnaturalfoodes.shop/product-category/vitamin-d-3-1000iu/