Available Technology

PROCESS AND ARTICLE FOR ELECTRONICALLY SYNTHESIZING LIGHT

This invention is a method and apparatus for optical-to-microwave conversion and synthesis of lightwaves directly with electronics. The invention's electronic synthesizer for light creates a frequency comb in which all the modes of the comb are directly traceable to one electronic signal. It is composed of four essential pieces: an electro-optic modulation (EOM) frequency comb, novel optical-domain filtering of electronic noise, a new design for the nonlinear optics needed for spectral broadening of >1 picosecond (ps) optical pulses, and an f-2f nonlinear interferometer for carrier-phase detection. The invention works by imposing a microwave-electronic modulation onto a continuous-wave (CW) laser to create an EOM frequency comb. The electronic modulation transforms the CW laser into a train of optical pulses at the microwave rate. We then use two novel optical-domain processes that enable electronic synthesis of light, optical filtering of electronic noise and spectral broadening with >1 ps pulses to generate a coherent supercontinuum. With the supercontinuum, we use the f-2f technique for carrier-phase detection, which directly links the CW laser frequency to the microwave-electronic modulation signal.

The invention's EOM frequency comb will enable diverse applications, including electro-optical signal conversion, spectroscopic detection of molecules, coherent optical communications and optical imaging, and as a diagnostic tool for medical imaging. Our invention brings highly unique features to these applications from a widely tunable frequency comb with wide mode spacing to a coherent optical-microwave interface to robust, deterministic frequency comb generation.

Abstract: 

This invention is a method and apparatus for electronic synthesis of light based on an electro-optic modulation (EOM) frequency comb. The invention provides a phase-coherent link between light and microwave radiation using linear electro-optics. It is composed of four interconnected components. In the first component, the invention utilizes periodic electro-optic modulation at microwave rates to transform a continuous-wave (CW) laser into a train of picosecond light pulses. The second component is nonlinear-fiber broadening of this EOM frequency comb to produce a supercontinuum with 160 THz of bandwidth. The third component is optical filtering of the EOM comb that virtually eliminates electronic-noise-induced decoherence of the supercontinuum. The fourth component is f-2f self-referencing that yields the carrier-envelope offset frequency of the EOM comb, which enables measurement and control of the CW laser frequency calibrated by the SI definitions of time and frequency.

Benefits: 

This invention introduces the concept of lightwave synthesis directly with electronics. The overall concept of this invention involving electro-optic modulation (EOM) comb system design and mitigation of electronic noise is completely new – that an electronically derived frequency comb, the EOM comb, can be used to synthesize and count cycles of light. This invention hinges upon two new innovations: optical filtering of electronic thermal noise and ultrabroadband supercontinuum generation with >1 ps optical pulses. These are new, critical, innovative, and enabling features. Additionally, the EOM frequency comb invention offers a new technological route for synthesis of lightwaves that offers important features that do not currently exist. In particular, the EOM comb synthesizer supports high mode spacing in the 10+ GHz range that targets applications in communications, spectroscopy, and sensing in which optically resolving comb modes is critical. EOM combs also offer wide frequency tuning to match application needs.

Inventors: 

Scott Papp, Scott Diddams, Katja Eha, and Daniel Cole

Patent Number: 
10,048,567
Technology Type(s): 
Laser and Optics, Manufacturing, Electronics, Optical Frequency Measurements, Micro- and Optoelectronics, Healthcare
Internal Laboratory Ref #: 
16-028US1
Patent Issue Date: 
August 14, 2018
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