Integrated multiple wavelength stabilization on a multi-channel cavity for a transportable optical clock

We present a simple, compact, and efficient scheme for integrated multiple wavelength stabilization and continuous operation of a transportable ⁴⁰Ca⁺ optical clock using a multi-channel cavity. The fractional frequency instability of 729 nm clock laser is ∼ 1.5 ×10^-15 at 10 s with an approximate linewidth of 1 Hz. Meanwhile, frequency fluctuations of all the other lasers are less than ± 330 kHz/day. The one-day stability of this clock is measured as ∼ 5 ×10^-17 through 72 h continuous operation. This scheme is potentially useful for the realization of next-generation transportable optical clocks and other metrological systems.