Fig. 1. Experimental set-up for frequency control of the 759 nm laser. The solid lines represent the light path, while the dashed lines represent the electrical path. Ti:sapphire fs laser, Ti:sapphire femtosecond laser; PCF, photonic crystal fiber; PPKTP, periodically poled KTiOPO₄; DDS, direct digital synthesizer; EOM, electro-optic modulator; PZT, piezo-transducer; Ti:sapphire cw laser, Ti:sapphire continuous wave laser; PD, photo detector; SYN, RF synthesizer.

Fig. 2. (a) Simplified experimental set-up for optical clock operation. (b) Rabi spectrum with a probe time of 200 ms.

Fig. 3. Frequency noise induced by a 10-m-long fiber (red dots) and in-loop frequency noise during frequency transfer (black squares).

Fig. 4. (a) Timing sequence of self-comparison. Blue and purple lines indicate two independent stabilizations. (b) Scalar lattice shift at U = 200E_r measured by interleaving between a trap depth of 158(4)E_r and 226(4)E_r at different lattice frequencies.