Generation of a frequency comb of squeezing in an optical parametric oscillator

The multimode operation of an optical parametric oscillator (OPO) operating below threshold is calculated. We predict that squeezing can be generated in a comb that is limited only by the phase matching bandwidth of the OPO. Effects of technical noise on the squeezing spectrum are investigated. It is shown that maximal squeezing can be obtained at high frequency even in the presence of seed laser noise and cavity length fluctuations. Furthermore the spectrum obtained by detuning the laser frequency off OPO cavity resonance is calculated.

Figure 1

Schematic of quadrature squeezing system. (a) Overall system where ${\eta }_1$ and ${\eta }_2$ are beamsplitter reflectivities. (b) Detailed schematic of OPO.

Figure 2

Variance of the phase quadrature in an OPO.

Figure 3

Phase quadrature squeezing of a seeded OPO: (a) As a function of frequency with seed power ${\mid {\alpha }_{\mathit{\text{in}}}∕{\beta }_{\mathit{\text{in}}}\mid }^2={10}^{–3}$ (broken line) and 0 (continuous line). (b) As a function of seed power at $f=$10 MHz (broken line) and 10 GHz (continuous line).

Figure 4

Variance of the phase quadrature (left column) and cavity transmission (right column) in an OPO with $\Delta =\left(\mathrm{a}\right)$ $0.1\mathrm{GHz}$, (b) $2.5\mathrm{GHz}$, and (c) $5\mathrm{GHz}$.

Figure 5

Phase and amplitude quadrature variances for $\Delta =1\mathrm{GHz}$.

Figure 6

Phase quadrature, amplitude quadrature, and total quadrature variances with $\Delta =\left(\mathrm{a}\right)$ $0\mathrm{GHz}$ and (b) $0.1\mathrm{GHz}$.