Injection-locked diode laser current modulation for Pound-Drever-Hall frequency stabilization using transfer cavities

A phase modulated RF current source is applied to an injection locked diode laser operating at $780\text{unit}nm$. This produces tunable phase modulated sidebands of the laser suitable for stabilizing the length of an optical transfer cavity using the Pound-Drever-Hall technique. The Pound-Drever-Hall signal is anti-symmetric about the lock point, despite the presence of significant diode laser amplitude modulation. The stabilized optical transfer cavity is used to frequency stabilize a 776 nm external cavity diode laser. The stability and tunability of this transfer cavity locked laser is established by observation of the hyperfine components of the ${}^{87}$Rb $5P_{3\mathrm{/}2}-5D_{5\mathrm{/}2}$ transition in a vapor cell.