  The conventional approach to perform two-qubit gate operations in trapped
ions relies on exciting the ions on motional sidebands with laser light, which
is an inherently slow process. One way to implement a fast entangling gate
protocol requires a suitable pulsed laser to increase the gate speed by orders
of magnitude. However, the realization of such a fast entangling gate operation
presents a big technical challenge, as such the required laser source is not
available off-the-shelf. For this, we have engineered an ultrafast entangling
gate source based on a frequency comb. The source generates bursts of several
hundred mode-locked pulses with pulse energy $\sim$800 pJ at 5 GHz repetition
rate at 393.3 nm and complies with all requirements for implementing a fast
two-qubit gate operation. Using a single, chirped ultraviolet pulse, we
demonstrate a rapid adiabatic passage in a Ca$^+$ ion. To verify the
applicability and projected performance of the laser system for inducing
entangling gates we run simulations based on our source parameters. The gate
time can be faster than a trap period with an error approaching $10^{-4}$.
