Coherence properties of a broadband femtosecond mid-IR optical parametric oscillator operating at degeneracy

We study coherence properties of a χ^(2) optical parametric oscillator (OPO), which produces 2/3-octave-wide spectrum centered at the subharmonic (3120 nm) of the femtosecond pump laser. Our method consists of interfering the outputs of two identical, but independent OPOs pumped by the same laser. We demonstrate that the two OPOs show stable spatial and temporal interference and are mutually locked in frequency and in phase. By observing a collective heterodyne beat signal between the two OPOs we show that one can deterministically choose, by cavity length adjustment, between the two frequency states corresponding to the two sets of modes shifted with respect to each other by half of the laser pulse repetition rate. Moreover, we observe that the existence of two opposite phase states, a known common feature of a parametrically driven n = 2 subharmonic oscillator, reveals itself in our experiment as a common phase, 0 or π, being established through the whole set of some 300 thousand longitudinal modes

All-Optical Quantum Random Bit Generation from Intrinsically Binary Phase of Parametric Oscillators

True random number generators (RNGs) are desirable for applications ranging from cryptogra- phy to computer simulations. Quantum phenomena prove to be attractive for physical RNGs due to their fundamental randomness and immunity to attack [1]- [5]. Optical parametric down conversion is an essential element in most quantum optical experiments including optical squeezing [9], and generation of entangled photons [10]. In an optical parametric oscillator (OPO), photons generated through spontaneous down conversion of the pump initiate the oscillation in the absence of other inputs [11, 12]. This quantum process is the dominant effect during the oscillation build-up, leading to selection of one of the two possible phase states above threshold in a degenerate OPO [13]. Building on this, we demonstrate a novel all-optical quantum RNG in which the photodetection is not a part of the random process, and no post processing is required for the generated bit sequence. We implement a synchronously pumped twin degenerate OPO, which comprises two identical independent OPOs in a single cavity, and measure the relative phase states of the OPO outputs above threshold as a bit value. We show that the outcome is statistically random with 99% confidence. With the use of micro- and nanoscale OPO resonators, this technique offers a promise for simple, robust, and high-speed on-chip all-optical quantum random number generators

Coherence properties of a broadband femtosecond mid-IR optical parametric oscillator operating at degeneracy

We study coherence properties of a χ^(2) optical parametric oscillator (OPO), which produces 2/3-octave-wide spectrum centered at the subharmonic (3120 nm) of the femtosecond pump laser. Our method consists of interfering the outputs of two identical, but independent OPOs pumped by the same laser. We demonstrate that the two OPOs show stable spatial and temporal interference and are mutually locked in frequency and in phase. By observing a collective heterodyne beat signal between the two OPOs we show that one can deterministically choose, by cavity length adjustment, between the two frequency states corresponding to the two sets of modes shifted with respect to each other by half of the laser pulse repetition rate. Moreover, we observe that the existence of two opposite phase states, a known common feature of a parametrically driven n = 2 subharmonic oscillator, reveals itself in our experiment as a common phase, 0 or π, being established through the whole set of some 300 thousand longitudinal modes

Carrier Envelope Offset Of Nondegenerate, Doubly-Resonant, Midinfrared Gaas Optical Parametric Oscillators

We demonstrate that the carrier-envelope offset frequency of a mid-infrared frequency comb from a nondegenerate and doubly-resonant GaAs-based optical parametric oscillator is locked to that of the 2 μm thulium-fiber pump laser. © OSA 2013

Carrier Envelope Offset Of Nondegenerate, Doubly-Resonant, Midinfrared Gaas Optical Parametric Oscillators

We demonstrate that the carrier-envelope offset frequency of a mid-infrared frequency comb from a nondegenerate and doubly-resonant GaAs-based optical parametric oscillator is locked to that of the 2 μm thulium-fiber pump laser. © 2013 The Optical Society

Mid-Ir Frequency Comb With Sub-Hertz Residual Linewidth From A Doubly-Resonant Opgaas Opo

We show a mid-infrared source that is a low-threshold, doubly-resonant OPGaAs OPO pumped by a Tm fiber frequency comb laser, with a fully stabilized comb spectrum with sub-Hz relative linewidths. © 2013 IEEE

Media 1: All-optical quantum random bit generation from intrinsically binary phase of parametric oscillators

Originally published in Optics Express on 13 August 2012 (oe-20-17-19322