Generation of broadband coherent laser pulses based on adiabatic four-wave mixing in waveguides and fiber

Patent metadata

Field	Value
Publication number	US-11487185-B2
Application number	US-201917055554-A
Country	US
Kind code	B2
Filing date	May 14, 2019
Priority date	May 14, 2018
Publication date	Nov 1, 2022
Grant date	Nov 1, 2022

Abstract

The technology disclosed in this patent document can be used to implement an optical device for generating broadband optical pulses, including an optical waveguide having different waveguide structures at different locations along the optical waveguide and with varying dimensions or pressure gradient that change adiabatically along the different locations to enable non-linear four wave mixing over a broad spectral range.

First claim

What is claimed is what is disclosed and illustrated, including:

1. An optical device for frequency conversion based on adiabatic four wave mixing to produce an idler laser beam, comprising:
a pump laser module to produce a pump laser beam having pump laser pulses at pump laser wavelengths;
a signal laser beam module to produce a signal laser beam having signal laser pulses at a signal laser wavelength;
a segment of fiber having an input port and an output port, the input port coupled to receive the signal laser beam and the pump laser beam to exhibit a spatially varying optical dispersion as an adiabatic four wave mixing medium to convert energy at the signal laser wavelength into the idler laser beam at an idler wavelength shorter than the signal laser wavelength, wherein the input port of the segment of fiber has a negative wave-vector mismatch and the output port of the segment of fiber has a positive wave-vector mismatch, or the input port of the segment of fiber has a positive wave-vector mismatch and the output port of the segment of fiber has a negative wave-vector mismatch; and
an output port coupled to the output port of the segment of fiber to select the idler laser beam as an output of the optical device.

2. The device as in claim 1 , wherein the segment of fiber includes a spatially tapered fiber with an adiabatic taper rate satisfying a condition for adiabatic four wave mixing, wherein the condition for adiabatic four wave mixing includes

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wherein Δk eff is an effective wave-vector mismatch, wherein κ is a coupling coefficient, and wherein the derivatives are with respect to a propagation distance of light in the tapered fiber.

3. The device as in claim 1 , wherein a photon conversion ratio (PCR) of the segment of fiber is expressed by 1−exp(−8πκ 2 /|dΔk/dz|), wherein κ=2√{square root over (γ sig γ idl P A P B )} represents a nonlinear coupling strength and |dΔk/dz| represents a sweeping rate of Δk, which is wave-vector mismatch for adiabatic four wave mixing,
wherein y sig and y idl are nonlinear coefficients for signal and idler waves, respective,
and wherein P A and P B are pump powers for pump light beams for the non-linear four wave mixing.

4. The device as in claim 1 , wherein the segment of fiber tapers from the input port towards the output port of the segment of fiber.

5. The device as in claim 1 , wherein the segment of fiber includes a photonic crystal fiber (PCF).

6. The device as in claim 5 , wherein the PCF includes an air-core.

7. The device as in claim 5 , wherein the PCF includes a solid core with high numerical apertures.

8. The device as in claim 1 , wherein the segment of fiber includes a hollow capillary fiber.

9. The device as in claim 1 , wherein the segment of fiber includes a spatially untapered fiber with an adiabatic pressure gradient with rate satisfying a condition for adiabatic four wave mixing, wherein the condition for adiabatic four wave mixing includes

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wherein Δk eff is an effective wave-vector mismatch, wherein κ is a coupling coefficient, and wherein the derivatives are with respect to a propagation distance of light in the fiber.

10. The device as in claim 1 , wherein the segment of fiber includes a type of fiber in which a longitudinally varying spatial structure or pressure gradient are used to satisfy a condition for adiabatic four wave mixing, wherein the condition for adiabatic four wave mixing includes

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Assignees

• Univ Cornell
• Univ Ramot

Inventors

• Suchowski Haim
• Dahan Asaf
• Bahar Eyal
• Moses Jeffrey
• Ding Xiaoyue

Classifications

• G02B6/02376

  Longitudinal variation along fibre axis direction, e.g. tapered holes · CPC title

• G02F1/3536 Primary

  Four-wave interaction · CPC title

• G02F2202/32

  Photonic crystals · CPC title

• G02F1/365

  in an optical waveguide structure (G02F1/377, {G02F1/395} take precedence) · CPC title

• G02F2201/02

  fibre · CPC title