# US 11,444,698 B2 · Optical transmitter operating burst mode and control method of optical transmitter operating burst mode

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- Number: US 11,444,698 B2
- Document ID: US11444698B2
- Status: Granted
- Kind: B2
- Application number: 17/118,625
- Filed: 2020-12-11
- Published: 2021-04-15
- Granted: 2022-09-13
- Earliest claimed: 2017-07-29
- Applicants: Jeongsoo Kim; PICadvanced S.A.
- Inventors: Jeongsoo Kim
- Web page: https://patentgrep.com/patent/US11444698B2

## CPC

- H04B 10/564: Power control
- H01S 5/02453: {Heating, e.g. the laser is heated for stabilisation against temperature fluctuations of the environment (H01S5/0612 takes precedence, for monolithically integrated heaters see also H01S5/0261)}
- H01S 5/0428: {for applying pulses to the laser}
- H01S 5/0612: {controlled by temperature}
- H01S 5/06216: {Pulse modulation or generation}
- H01S 5/0622: {Controlling the frequency of the radiation}
- H01S 5/06804: {by monitoring an external parameter, e.g. temperature}
- H01S 5/0683: by monitoring the optical output parameters
- H04B 10/2507: for the reduction or elimination of distortion or dispersion
- H04B 10/272: Star-type networks {or tree-type networks}
- H04B 10/504: {using direct modulation}
- H04B 10/572: Wavelength control
- H04B 10/6911: {Photodiode bias control, e.g. for compensating temperature variations}
- H04B: TRANSMISSION
- 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

## Abstract

The present invention provides an optical transmitter including a semiconductor laser and a control method thereof for preventing crosstalk between channels in an NG-PON2 with a 100 GHz channel spacing by reducing a wavelength drift of the semiconductor laser. The wavelength drift occurs between a few nanoseconds and a few hundreds of nanoseconds from the beginning of a burst when the semiconductor laser is operated in a burst-mode.

## Claims

### Claim 1

A method for providing power and a data signal to an optical transmitter including a light source, comprising performing:
a first applying step of applying first driving power to the light source, an amplitude of the first driving power increasing with a first average slope in a time domain, the first applying step being performed after receiving a trigger signal;
a second applying step of applying a first electrical modulated signal to the light source, the second applying step being performed after a first predetermined time elapses from when the trigger signal is received; and
a providing step of a second electrical modulated signal to the light source, the second electrical modulated signal including data for being transmitted, the providing step being performed after a second predetermined time elapses from starting of the second applying step.

### Claim 2 (depends on 1)

The method of claim 1, further comprising performing a third applying step of applying second driving power to the light source, the third applying step being performed after receiving the trigger signal.

### Claim 3 (depends on 2)

The method of claim 2, wherein the third applying step comprises applying the second driving power whose amplitude increases with a second average slope.

### Claim 4 (depends on 3)

The method of claim 3, wherein the second average slope is greater than the first average slope.

### Claim 5 (depends on 3)

The method of claim 3, wherein the third applying step comprises: after the first electrical modulated signal has been applied to the light source, stopping the applying of the second driving power at a time before the first driving power reaches a reference value.

### Claim 6 (depends on 3)

The method of claim 3, wherein the second applying step begins after a time of 30 nanoseconds to 70 nanoseconds elapses from the receiving of the trigger signal,
wherein the third applying step ends after a time of 40 nanoseconds to 80 nanoseconds elapses from the receiving of the trigger signal, and
wherein the third applying step ends after the second applying step begins.

### Claim 7 (depends on 3)

The method of claim 3, wherein the third applying step ends upon a maximum of the applied second driving power being lower than a predetermined level.

### Claim 8 (depends on 1)

The method of claim 1, wherein the first driving power and the first and second electrical modulated signals are provided to the optical transmitter.

### Claim 9

An optical transmitter transmitting an optical data signal using a light source, comprising:
a driver configured to:
apply first driving power to the light source after receiving a trigger signal, an amplitude of the first driving power increasing with a first average slope in a time domain;
apply a first electrical modulated signal to the light source after a first predetermined time elapses from when the trigger signal is received; and
apply a second electrical modulated signal to the light source after a second predetermined time elapses from starting of the applying of the first electrical modulated signal, wherein the second electrical modulated signal including data for being transmitted; and
the light source configured to receive the first driving power and the first and second electrical modulated signals from the driver and transmit the optical data signal including the data to an optical receiver.

### Claim 10 (depends on 9)

The optical transmitter of claim 9, wherein the driver is further configured to apply second driving power separately from the first driving power for driving the light source, subsequent to the receiving of the trigger signal.

### Claim 11 (depends on 9)

The optical transmitter of claim 9, wherein the driver is further configured to apply the second driving power increasing with a second average slope, subsequent to the receiving of the trigger signal.

### Claim 12 (depends on 11)

The optical transmitter of claim 11, wherein the second average slope is greater than the first average slope.

### Claim 13 (depends on 10)

The optical transmitter of claim 10, wherein the driver is configured to stop the applying of the second driving power before the first driving power reaches a reference value, after the first electrical modulated signal has been applied to the light source.

### Claim 14 (depends on 12)

The optical transmitter of claim 12, wherein the driver is further configured to stop the applying of the second driving power upon a maximum of the applied second driving power being lower than a predetermined level.

### Claim 15 (depends on 9)

The optical transmitter of claim 9, wherein the driver is further configured to:
provide the first electrical modulated signal to the light source after a time of 30 nanoseconds to 70 nanoseconds elapses from the receiving of the trigger signal;
stop the applying of the second driving power for driving the light source after a time of 40 nanoseconds to 80 nanoseconds elapses from the receiving of the trigger signal,
wherein the applying of the second driving power ends after the applying of the first electrical modulated signal to the light source.

### Claim 16

A method for providing power and a data signal to an optical transmitter including a light source, performing:
applying first driving power, using a first power source, to the light source in response to receiving of a trigger signal, wherein an amplitude of the first driving power increases with a first average slope in a time domain, and the applying of the first driving power starts at a first time point after the receiving of the trigger signal; and
applying second driving power using a second power source different from the first power source, to the light source in response to the receiving of the trigger signal, wherein an amplitude of the second driving power increases with a second average slope in the time domain, the applying of the second driving power starts at a second time point after the receiving of the trigger signal, and the second time point is later than the first time point.

### Claim 17 (depends on 16)

The method of claim 16, further comprising:
applying a first electrical modulated signal to the light source in response to the receiving of the trigger signal, the applying of the first electrical modulated signal being performed at a third time point after receiving the trigger signal.

### Claim 18 (depends on 17)

The method of claim 17, further comprising:
applying a second electrical modulated signal including data for being transmitted in response to the receiving of the trigger signal, the applying of the second electrical modulated signal starts at a fourth time point after starting of the applying of the first electrical modulated signal.

### Claim 19 (depends on 16)

The method of claim 16, wherein the second average slope is greater than the first average slope.

### Claim 20 (depends on 16)

The method of claim 16, wherein the applying of the second driving power comprises: after the first electrical modulated signal has been applied to the light source, stopping the applying of the second driving power at a time before the first driving power reaches a reference value.