US 9,178,623 B2 · Photon phase modulating system

Abstract

The present invention utilizes a high-speed serial data transceiver to generate two high-speed electric pulse signals. After passing through a gain network, the signals are used for driving an electro-optic phase modulator (PM) so as to realize phase modulation of photon signals. The present invention may directly use a high-speed digital signal to realize a four-phase modulation function needed by the BB84 quantum key distribution protocol without using a digital to analog converter or an analog switch. This can prevent modulation rate from being restricted by links including digital-to-analog conversion, switching of the analog and the like. A dual-electrode electro-optic phase modulator scheme can also effectively reduce requirements for amplitude of a modulation driving signal, thus facilitating realization of high-speed phase modulation, which meets requirements of quantum key distribution.

Claims25

Dependent claims

A photon phase modulating system, comprising:

a random number generating unit, configured to generate a random digital number;
a parallel/serial converting unit, configured to perform parallel/serial conversion on the random digital number generated by the random number generating unit to obtain a serial random digital signal;
a high-speed serial transceiver, configured to receive the serial random digital signals generated by the parallel/serial converting unit and outputting two separate digital driving signals;
a gain control network, configured to perform gain control on the two separate digital driving signals respectively, and to generate two driving signals for driving an electro-optic phase modulator;
and
the electro-optic phase modulator having two separate modulation electrodes, each of which receives a corresponding one of the two driving signals, the electro-optic phase being configured to perform phase modulation on an inputted photon and implement four-phase modulation on the inputted photon based on a combination of the two separate digital driving signals.

3 more elements

A photon phase modulating system, comprising:

a random number generating unit, configured to generate a random digital number;
a parallel/serial converting unit, configured to perform parallel/serial conversion on the random digital number generated by the random number generating unit to obtain a serials random digital signal;
a high-speed serial transceiver, configured to receive the serial random digital signal generated by the parallel/serial converting unit and output two separate digital driving signals;
an adder circuit, configured to perform analogue summation on the two separate digital driving signals to obtain a four-level driving signal;
a gain control network, configured to perform gain control on the four-level driving signal, and to generate a four-level driving signal for driving an electro-optic phase modulator;
and
the electro-optic phase modulator having a single modulation electrode, which receives the four-level driving signal for driving the electro-optic phase modulator, the electro-optic phase modulator being configured to perform phase modulation on an inputted photon and implement four-phase modulation on the inputted photon based on a combination of the two separate digital driving signals.

4 more elements

A photon phase modulating system, comprising:

a random number generating unit, configured to generate a random digital number;
a parallel/serial converting unit, configured to perform parallel/serial conversion on the random digital number generated by the random number generating unit to obtain a serial random digital signal;
a high-speed serial transceiver, configured to receive the serial's random digital signal generated by the parallel/serial converting unit and output two separate digital driving signals;
a gain control network, configured to perform gain control on the two separate digital driving signals respectively and generate two driving signals;
an adder circuit, configured to perform analogue summation on the two driving signals to obtain a four-level driving signal for driving an electro-optic phase modulator;
and
the electro-optic phase modulator having a single modulation electrode, which receives the four-level driving signal for driving the electro-optic phase modulator, the electro-optic phase modulator being configured to perform phase modulation on an inputted photon and implement four-phase modulation on the inputted photon based on a combination of the two separate digital driving signals.

4 more elements

Dependencies are inferred from the claim text.

Photon phase modulating system

Life of this patent

Photon phase modulating system

Life of this patent

Abstract

Claims25