# US 11,029,476 B2 · Injection locked multi-wavelength optical source

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- Number: US 11,029,476 B2
- Document ID: US11029476B2
- Status: Granted
- Kind: B2
- Application number: 16/582,907
- Filed: 2019-09-25
- Published: 2021-03-25
- Granted: 2021-06-08
- Earliest claimed: 2019-09-25
- Assignees: Hewlett Packard Enterprise Development LP
- Applicants: Hewlett Packard Enterprise Development LP
- Inventors: Di Liang; Zhixin Liu
- Web page: https://patentgrep.com/patent/US11029476B2

## CPC

- G02B 6/43: Arrangements comprising a plurality of opto-electronic elements and associated optical interconnections
- H01S 5/4006: {Injection locking}
- G02B 6/29343: {Cascade of loop resonators}
- G02B 6/29382: {including at least adding or dropping a signal, i.e. passing the majority of signals}
- G02B 6/4215: {the intermediate optical elements being wavelength selective optical elements, e.g. variable wavelength optical modules or wavelength lockers (G02B6/4246 takes precedence)}
- H01S 5/026: Monolithically integrated components, e.g. waveguides, monitoring photo-detectors, drivers (stabilisation of output H01S5/06)
- H01S 5/0657: {Mode locking, i.e. generation of pulses at a frequency corresponding to a roundtrip in the cavity}
- H01S 5/1071: {Ring-lasers}
- H01S 5/1092: {Multi-wavelength lasing}
- H01S 5/4025: {Array arrangements, e.g. constituted by discrete laser diodes or laser bar (H01S5/42 takes precedence)}
- H04B 10/503: {Laser transmitters}
- H04B 10/506: {Multiwavelength transmitters}
- H04B 10/67: Optical arrangements in the receiver
- H04J 14/02: Wavelength-division multiplex systems
- G02B 6/12007: {forming wavelength selective elements, e.g. multiplexer, demultiplexer}
- H01S 5/4068: {with lateral coupling by axially offset or by merging waveguides, e.g. Y-couplers}
- H01S 5/4087: {emitting more than one wavelength}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- 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
- H04B: TRANSMISSION
- H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S)

## Abstract

Examples herein relate to optical systems. In particular, implementations herein relate to an optical system including an optical transmitter configured to transmit optical signals. The optical transmitter includes a first optical source configured to emit light having different wavelengths, a waveguide, and an optical coupler configured to couple the emitted light from the first optical source to the waveguide. The optical transmitter further includes an array of two or more second optical sources coupled to the waveguide, each of the two or more second optical sources configured to be injection locked to a different respective wavelength of the emitted light transmitted via the waveguide from the first optical source. In some implementations, the first optical source is a master comb laser and the two or more second optical sources are slave ring lasers.

## Claims

### Claim 1

An optical system comprising:
an optical transmitter configured to transmit optical signals, the optical transmitter comprising:
a first optical source configured to emit light having different wavelengths;
a waveguide;
an optical coupler configured to couple the emitted light from the first optical source to the waveguide; and
an array of two or more second optical sources coupled to the waveguide, each of the two or more second optical sources configured to be injection locked to a different respective wavelength of the emitted light from the first optical source, the emitted light transmitted via the waveguide coupling the first optical source to the array of two or more second optical sources; and
an optical receiver configured to receive the optical signals from the optical transmitter via an optical link after different respective wavelengths of the emitted light are injected into the respective two or more second optical sources, the optical receiver comprising:
a second waveguide;
an array of ring resonators coupled to the second waveguide and configured to be tuned to different resonant wavelengths respectively corresponding to different wavelengths of the emitted light from the first optical source; and
an array of photodetectors, each photodetector coupled to a respective ring resonator of the array of ring resonators.

### Claim 2 (depends on 1)

The optical system of claim 1, wherein the first optical source comprises a multi-wavelength comb laser.

### Claim 3 (depends on 2)

The optical system of claim 2, wherein the array of two or more second optical sources comprises two or more ring lasers.

### Claim 4 (depends on 3)

The optical system of claim 3, wherein the two or more ring lasers are injection locked to the first optical source without an optical isolator positioned therebetween.

### Claim 5 (depends on 3)

The optical system of claim 3, wherein the waveguide comprises a bus waveguide, the two or more ring lasers being coupled to the bus waveguide.

### Claim 6 (depends on 1)

The optical system of claim 1, wherein the optical coupler comprises a grating coupler.

### Claim 7 (depends on 1)

The optical system of claim 1, further comprising:
a second waveguide;
a second optical coupler configured to couple the emitted light from the first optical source to the second waveguide; and
a second array of two or more second optical sources coupled to the second waveguide, each of the two or more second optical sources configured to be injection locked to a different respective wavelength of the emitted light transmitted via the second waveguide from the first optical source.

### Claim 8 (depends on 7)

The optical system of claim 7, wherein the emitted light from the first optical source is symmetrically output to the first and second waveguides such that the first array of two or more second optical sources and the second array of two or more second optical sources are injection locked to same respective wavelengths of the emitted light.

### Claim 9 (depends on 7)

The optical system of claim 7, further comprising an optical splitter to split the wavelengths of the light emitted from the first optical source between the first and second waveguides such that the first array of two or more second optical sources and the second array of two or more second optical sources are injection locked to different respective wavelengths of the emitted light.

### Claim 10 (depends on 7)

The optical system of claim 7, wherein the two or more second optical sources of the array and the two or more second optical sources of the second array comprise ring lasers injection locked to the first optical source without respective optical isolators positioned therebetween.

### Claim 11 (depends on 1)

The optical system of claim 1, wherein each photodetector is integrated with the respective ring resonator to form an array of wavelength-selective photodetectors.

### Claim 12

An injection locked multi-wavelength optical source comprising:
a master comb laser configured to emit light having multiple different wavelengths;
an array of two or more slave ring lasers, wherein each slave ring laser is injection locked to a different respective wavelength of the emitted light from the master comb laser; and
a waveguide coupled to both the master comb laser and the array of two or more slave ring lasers, the emitted light from the master comb laser being transmitted via the waveguide to the array of two or more slave ring lasers.

### Claim 13 (depends on 12)

The injection locked multi-wavelength optical source of claim 12, wherein the master comb laser and the array of two or more slave ring lasers are formed on or within a single chip.

### Claim 14 (depends on 12)

The injection locked multi-wavelength optical source of claim 12, wherein the master comb laser and the array of two or more slave ring lasers are heterogeneously integrated on a silicon on insulator substrate.

### Claim 15 (depends on 12)

The injection locked multi-wavelength optical source of claim 12, wherein the slave ring lasers are injection locked to the master comb laser without an optical isolator positioned therebetween.

### Claim 16 (depends on 12)

The injection locked multi-wavelength optical source of claim 12, further comprising a second array of two or more slave ring lasers, wherein each slave ring laser is injection locked to a different respective wavelength of the emitted light transmitted from the master comb laser, and wherein the emitted light from the master comb laser is symmetrically output to the first and second arrays of two or more slave ring lasers such that the first and second arrays of two or more slave ring lasers are injection locked to same respective wavelengths of the emitted light.

### Claim 17

A method of transmitting optical signals comprising:
emitting light having multiple different wavelengths from a master comb laser;
injection locking different respective wavelengths of the emitted light from the master comb laser to slave ring lasers of a first array of two or more slave ring lasers, the emitted light from the master comb laser transmitted to the first array of two or more slave ring lasers via a waveguide coupled to both the master comb laser and the first array of two or more slave ring lasers.

### Claim 18 (depends on 17)

The method of claim 17, wherein the two or more slave ring lasers are injection locked to the master comb laser without an optical isolator positioned therebetween.

### Claim 19 (depends on 17)

The method of claim 17, further comprising:
symmetrically outputting the emitted light from the master comb laser to the first array of two or more slave ring lasers and a second array of two or more slave ring lasers such that the first and second arrays of two or more slave ring lasers are injection locked to same respective wavelengths of the emitted light.