# US 2021/0242654 A1 · Octave-Spanning Soliton Comb

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- Number: US 2021/0242654 A1
- Document ID: US20210242654A1
- Status: Published application
- Kind: A1
- Application number: 17/166,411
- Filed: 2021-02-03
- Published: 2021-08-05
- Earliest claimed: 2020-02-03
- Assignees: Yale University
- Applicants: Yale University
- Inventors: Hongxing Tang; Xianwen Liu; Joshua Surya
- Web page: https://patentgrep.com/patent/US20210242654A1

## CPC

- H01S 3/06754: {Fibre amplifiers (H01S3/06708 takes precedence)}
- G02F 1/3528: {for producing a supercontinuum}
- G02F 1/37: for second-harmonic generation {(G02F1/3532 takes precedence)}
- H01S 3/06716: {Fibre compositions (per se C03C13/04)or doping with active elements (lasing materials in general H01S3/14)}
- H01S 3/1608: {erbium}
- G02F 1/3501: {Constructional details or arrangements of non-linear optical devices, e.g. shape of non-linear crystals}
- G02F 1/3507: {Arrangements comprising two or more nonlinear optical devices}
- G02F 1/3511: {Self-focusing or self-trapping of light; Light-induced birefringence; Induced optical Kerr-effect}
- G02F 1/3513: {Soliton propagation}
- G02F 2203/17: involving soliton waves
- G02F 2203/56: Frequency comb synthesizer
- H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS

## Abstract

The present invention provides octave-spanning optical frequency combs. The octave-spanning optical frequency combs employ microresonators having improved stability using a smaller form factor. In some embodiments, the octave-spanning optical frequency combs are fabricated using aluminum nitride (AlN). AlN is a more robust Kerr material for generating octave-spanning soliton comb (e.g., 1.5 octaves or more).

## Claims

### Claim 1

An octave-spanning optical frequency comb device, comprising:
an optical pathway having at least one entry and at least one exit;
at least one laser source positioned at the at least one entry; and
at least one microring resonator positioned adjacent to the optical pathway between the at least one entry and the at least one exit, wherein the at least one microring resonator comprises aluminum nitride (AlN).

### Claim 2 (depends on 1)

The device of claim 1, wherein the at least one laser source is a continuous wave (CW) laser.

### Claim 3 (depends on 1)

The device of claim 1, wherein the optical pathway further comprises a suppressed carrier single sideband modulator (SC-SSBM) positioned between the at least one laser source and the at least one octave soliton comb.

### Claim 4 (depends on 1)

The device of claim 1, wherein the optical pathway further comprises an amplifier positioned between the at least one laser source and the at least one octave soliton comb.

### Claim 5 (depends on 4)

The device of claim 4, wherein the filter is an erbium-doped fiber amplifier (EDFA).

### Claim 6 (depends on 1)

The device of claim 1, wherein the optical pathway further comprises a fiber polarization controller (FPC) positioned between the at least one laser source and the at least one octave soliton comb.

### Claim 7 (depends on 1)

The device of claim 1, wherein the at least one microring resonator comprises an oxide cladding.

### Claim 8 (depends on 7)

The device of claim 7, wherein the oxide cladding is silicon oxide.

### Claim 9 (depends on 1)

The device of claim 1, wherein the at least one microring resonator comprises a ring width and a ring radius.

### Claim 10 (depends on 9)

The device of claim 9, wherein the ring width is between about 0.5 μm to about 100 μm.

### Claim 11 (depends on 9)

The device of claim 9, wherein the ring radius is between about 10 μm to about 1000 μm.

### Claim 12 (depends on 1)

The device of claim 1, wherein the at least one microring resonator is fabricated by chemical vapor deposition of an AlN thin film on a substrate.

### Claim 13 (depends on 12)

The device of claim 12, wherein the chemical vapor deposition is metalorganic chemical vapor deposition (MOCVD).

### Claim 14 (depends on 12)

The device of claim 12, wherein the substrate is sapphire.

### Claim 15 (depends on 12)

The device of claim 12, wherein the AlN thin film comprises at least 0.5% thickness uniformity.

### Claim 16 (depends on 12)

The device of claim 12, wherein the AlN thin film comprises an annealing temperature of about 1700° C.

### Claim 17 (depends on 1)

The device of claim 1, wherein the device comprises an intrinsic optical Q factor of at least 3,000,000.

### Claim 18 (depends on 1)

The device of claim 1, wherein the at least one microring resonator comprises a ring width of 2.5 μm, a ring radius of 60 μm, a repetition frequency frep of 362 GHz, and a comb span of 1.2 octave.

### Claim 19 (depends on 1)

The device of claim 1, wherein the at least one microring resonator comprises a ring width of 3.3 μm, a ring radius of 100 μm, a repetition frequency frep of 216.5 GHz, and a comb span of 1.1 octave.

### Claim 20 (depends on 1)

The device of claim 1, wherein the comb span is at least 1.5 octaves.

### Claim 21 (depends on 1)

The device of claim 1, further comprising an electro-optical comb for repetition comprising a waveguide in resonance with the at least one microring resonator, at least one frequency second harmonic generation doubler, and a racetrack resonator.