Wavelength Drift Suppression for Burst-Mode Tunable EML Transmitter

Patent metadata

Field	Value
Publication number	US-2021203130-A1
Application number	US-201917057652-A
Country	US
Kind code	A1
Filing date	May 7, 2019
Priority date	May 21, 2018
Publication date	Jul 1, 2021
Grant date	—

Abstract

A method ( 900 ) includes delivering a first bias current (I GAIN ) to an anode of a gain-section diode ( 590 a ) and delivering a second bias current (I PH ) to an anode of a phase-section diode ( 590 b ). The method also includes receiving a burst mode signal ( 514 ) indicative of a burst-on state or a burst-on state, and sinking a first sink current (I SINK ) away from the first bias current when the burst mode signal is indicative of the burst-off state. When the burst mode signal transitions to be indicative of the burst-on state from the burst-off state, the method also includes sinking a second sink current away from the second bias current at the anode of the phase-section diode and ceasing the sinking of the first sink current away from the first bias current at the anode of the gain section diode.

First claim

1 . A method comprising:
delivering, by a laser driving circuit, a first bias current to an anode of a gain-section diode disposed on a shared substrate of a tunable laser; delivering, by the laser driving circuit, a second bias current to an anode of a phase-section diode disposed on the shared substrate of the tunable laser; receiving, at the laser driving circuit, a burst mode signal indicative of a burst-on state or a burst-off state; when the burst mode signal is indicative of the burst-off state, sinking, by the laser driving circuit, a first sink current away from the first bias current at the anode of the gain-section diode, the first sink current less than the first bias current delivered to the anode of the gain-section diode; and when the burst mode signal transitions to be indicative of the burst-on state from the burst-off state:
sinking, by the laser driving circuit, a second sink current away from the second bias current at the anode of the phase-section diode, the second sink current less than the second bias current delivered to the anode of the phase-section diode; and
ceasing, by the laser driving circuit, the sinking of the first sink current away from the first bias current at the anode of the gain-section diode.

2 . The method of claim 1 , wherein:
when the burst mode signal is indicative of the burst-off state, the gain-section diode receives a gain-section diode current equal to the first bias current minus the first sink current; and when the burst mode signal is indicative of the burst-on state, the phase-section diode receives a phase-section diode current equal to the second bias current minus the second sink current.

3 . The method of claim 1 , further comprising receiving, at the laser driving circuit, a sink current adjustment from a sinking stage of the laser driving circuit, the sink current adjustment configured to adjust the first sink current and the second sink current.

4 . The method of claim 3 , wherein the sinking stage comprises a differential pair of first and second metal oxide silicon field effect transistors MOSFETs, each MOSFET connected to a burst mode signal source, the first MOSFET connected to the anode of the phase-section diode, the second MOSFET connected to the anode of the gain-section diode.

5 . The method of claim 4 , wherein the first MOSFET is turned off and the second MOSFET is turned on to sink the first sink current away from the anode of the gain-section diode when the burst mode signal is indicative of the burst-off state.

6 . The method of claim 4 , wherein the first MOSFET is turned on and the second MOSFET is turned off to sink the second sink current away from the anode of the phase-section diode when the burst mode signal is indicative of the burst-on state

7 . The method of claim 1 , wherein the anode of the phase-section diode is connected to a second current source through an inductor.

8 . The method of claim 1 , wherein the anode of the phase-section diode is connected to an inductor through a resistor, wherein the inductor is connected to a voltage source.

9 . The method of claim 1 , further comprising, modulating, by the laser driving circuit, the laser by a capacitively coupled modulation stage of the laser driving circuit to an anode of an Electro-Absorption-section diode, resulting in an alternating current modulation current.

10 . The method of claim 9 , wherein the modulation stage comprises a differential pair of first and second MOSFETs, each MOSFET connected to a positive data signal source and a negative data signal source, the first MOSFET connected to a first resistor, the first resistor connected to a voltage source, the second MOSFET connected to a second resistor and to a capacitor, the second resistor connected to the voltage source, and the capacitor connected to the anode of the modulation-section diode.

11 . The method of claim 10 , wherein the capacitor is connected to an inductor connected to a variable voltage source.

12 . The method of claim 1 , wherein the tunable laser comprises an electro-absorption modulated tunable laser.

13 . A laser driving circuit comprising:
a first current source configured to deliver a first bias current to an anode of a gain-section diode disposed on a shared substrate of a tunable laser; a second current source configured to deliver a second bias current to an anode of a phase-section diode disposed on the shared substrate of the tunable laser; and a sinking stage configured to receive a burst mode signal indicative of a burst-on state or a burst-off state, the sinking stage configured to:
when the burst mode signal is indicative of the burst-off state, sink a first sink current away from the first bias current at the anode of the gain-section diode, the first sink current less than the first bias current received by the anode of the gain-section diode; and
when the burst mode signal transitions to be indicative of the burst-on state from the burst-off state:
sink a second sink current away from the second bias current at the anode of the phase-section diode, the second sink current less than the second bias current received by the anode of the phase-section diode; and
cease the sinking of the first sink current away from the first bias current at the anode of the gain-section diode.

14 . The laser driving circuit of claim 13 , wherein:
when the burst mode signal is indicative of the burst-off state, the gain-section diode receives a gain-section diode current equal to the first bias current minus the first sink current; and when the burst mode signal is indicative of the burst-on state, the phase-section diode receives a phase-section diode current equal to the second bias current minus the second sink current.

15 . The laser driving circuit of claim 13 , further comprising a third current source configured to adjust the first sink current and the second sink current.

16 . The laser driving circuit of claim 13 , wherein the sinking stage comprises a differential pair of first and second metal oxide silicon field effect transistors (MOSFETs), each MOSFET connected to a burst mode signal source, the first MOSFET connected to the anode of the phase-section diode, the second MOSFET connected to the anode of the gain-section diode.

17 . The laser driving circuit of claim 16 , wherein the first MOSFET is turned off and the second MOSFET is turned on to sink the first sink current away from the anode of the gain-section diode when the burst mode signal is indicative of the burst-off state.

18 . The laser driving circuit, wherein the first MOSFET is turned on and the second MOSFET is turned off to sink the second sink current away from the anode of the phase-section diode when the burst mode signal is indicative of the burst-on state.

19 . The laser driving circuit of claim 13 , wherein the anode of the phase-section diode is connected to the second current source through an inductor.

20 . The laser driving circuit of claim 13 , wherein the anode of the phase-section diode is connected to an inductor through a resistor, wherein the inductor is connected to a voltage source.

21 . The laser driving circuit of claim 13 , further comprising a modulation stage capacitively coupled to an anode of an Electro-Absorption-section diode, resulting in an alternating current modulation current.

22 . The laser driving circuit of claim 21 , wherein the modulation stage comprises a differential pair of first and second MOSFETs, each

Assignees

• Google Llc

Inventors

• Zhang Tao
• Lam Cedric Fung
• Yin Shuang
• Zhao Xiangjun
• Du Liang
• Jiang Changhong Joy
• Barratt Adam Edwin Taylor
• Desanti Claudio
• Nagarajan Muthu

Classifications

• H01S5/0427

  for applying modulation to the laser · CPC title

• H01S5/068

  Stabilisation of laser output parameters (H01S5/0625 takes precedence) · CPC title

• H01S5/042 Primary

  Electrical excitation {; Circuits therefor (monolithically integrated laser drive components H01S5/0261)} · CPC title

• H01S5/0625

  in multi-section lasers · CPC title

• H01S5/0428 Primary

  for applying pulses to the laser · CPC title