Fibre optic integrated quantum memory for light

A fibre optic quantum memory comprising:

• an optical fibre having an optical cavity integrated into the optical fibre, and reflective elements integrated within the optical fibre at opposing ends of the optical fibre, the respective elements forming a part of the optical fibre;
• a photon pair source integrated therein, the photon source comprising a photon pair generating mechanism for creating an entangled photon pair within the cavity using a spontaneous process;
• and
• a nonlinear optical switching mechanism for selectively extracting a photon of the photon pair from the cavity;
• wherein the first photon of the photon pair is resonant with the reflective elements in the cavity so the first photon is retained in the cavity,
• wherein the second photon of the photon pair is not resonant with the reflective elements so the second photon exits the cavity, and is used to herald a presence of the first photon retained in the cavity;
• wherein subsequent application of a nonlinear optical switching mechanism permits the photon retained in the cavity to exit the cavity.

A fibre optic quantum memory for storing a quantum state of light, comprising of:

• an optical fibre having an optical cavity integrated into the optical fibre;
• reflective elements integrated within the optical fibre at opposing ends of the optical fibre, the respective elements forming a part of the optical fibre;
• and
• a nonlinear optical switching mechanism that can temporarily modify at least one property of the reflective element such that it transmits an incident quantum state of light;
• wherein application of the switching mechanism temporarily modifies at least one property of at least one of the reflective elements such that the incident quantum light is transmitted into the cavity,
• wherein the absence of the switching mechanism means that the quantum light is trapped in the cavity between the two reflective elements;
• wherein a subsequent application of the switching mechanism temporarily modifies at least one property of a reflective element such that the trapped quantum light exits the cavity;
• and
• wherein quantum information encoded in the quantum light is preserved during storage in the cavity.