US 2026/0074790 A1Published application

Event timing-based method and apparatus for fiber-optic frequency transfer

AssigneesJinan Institute of Quantum Technology, Hefei National Laboratory

InventorsFaxi CHEN, Libo LI, Kan ZHAO, Yubo XIN, Xianbin SHAO, Pingan MA, Jia SUN, Chuanxiang WU, Haifeng JIANG

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Abstract

An event timing-based method and apparatus for fiber-optic frequency transfer are provided, relating to the fields of time-frequency transfer and precision time measurement. According to the method, an event timer is used to detect a time stamp of each rising edge of a radio frequency (RF) signal, which reflects a link delay jitter, a reference time stamp is subtracted from the time stamp to obtain a phase error, and an actuator is driven to compensate the phase error, thereby improving tolerance of a system to link noise while ensuring the stability of optical frequency transfer. Thus, the link delay jitter is suppressed, ensuring that a phase of an output transferred beam remains in long-term stability with a phase of an input reference light.

Claims10

Dependent claims

An event timing-based method for fiber-optic frequency transfer, comprising:

splitting a reference beam generated at a sending end into a first laser beam and a second laser beam via a beam splitter;
performing frequency modulation on the first laser beam by an acousto-optic modulator (AOM), and transmitting the first laser beam after the frequency modulation to a receiving end through an optical fiber link;
splitting the first laser beam into a third laser beam and a fourth laser beam by a semi-reflective and semi-transmissive Faraday rotator mirror at the receiving end, wherein the third laser beam is outputted as a transferred beam after passing through the semi-reflective and semi-transmissive Faraday rotator mirror, and the fourth laser beam is reflected by the semi-reflective and semi-transmissive Faraday rotator mirror to pass through the optical fiber link, the AOM and the beam splitter to reach a photodetector;
reflecting, by a Faraday rotator mirror, the second laser beam to enter the photodetector to beat with the fourth laser beam reflected by the semi-reflective and semi-transmissive Faraday rotator mirror to generate a beat signal;
acquiring a timestamp of a rising edge of the beat signal, wherein the timestamp is recorded by an event timer;
obtaining phase error data based on the timestamp of the rising edge of the beat signal and a reference timestamp;
and
performing phase compensation on the optical fiber link based on the phase error data.

5 more elements

An event timing-based apparatus for fiber-optic frequency transfer, comprising a sending end and a receiving end, wherein

the sending end comprises:
a reference beam input end, a beam splitter, an acousto-optic modulator (AOM), a photodetector, a Faraday rotator mirror, an event timer, a reference timestamp module and a phase compensation module, wherein
the reference beam input end is configured to generate a reference beam;
the beam splitter is configured to split the reference beam into a first laser beam and a second laser beam,
the AOM is configured to perform frequency modulation on the first laser beam, wherein the first laser beam after the frequency modulation is transmitted to the receiving end through an optical fiber link, and is split into a third laser beam and a fourth laser beam at the receiving end;
and
the receiving end comprises a semi-reflective and semi-transmissive Faraday rotator mirror, wherein the semi-transmissive Faraday rotator mirror is configured to split the first laser beam
into the third laser beam and the fourth laser beam, and the third laser beam is outputted as a transferred beam after passing through the semi-reflective and semi-transmissive Faraday rotator mirror, the fourth laser beam is reflected by the semi-reflective and semi-transmissive Faraday rotator mirror to pass through the optical fiber link, the AOM and the beam splitter to reach the photodetector, and
the Faraday rotator mirror is configured to reflect the second laser beam to enter the photodetector to beat with the fourth laser beam reflected by the semi-reflective and semi-transmissive Faraday rotator mirror to generate a beat signal;
the photodetector is configured to generate the beat signal;
the event timer is configured to record a timestamp of a rising edge of the beat signal, and phase error data is obtained based on the timestamp of the rising edge of the beat signal and a reference timestamp generated by the reference timestamp module;
and
the phase compensation module is configured to perform phase compensation on the optical fiber link based on the phase error data.

10 more elements

Dependencies are inferred from the claim text.