Arrayed waveguide grating based hybrid integrated laser having adjustable external cavity

Patent metadata

Field	Value
Publication number	US-10416379-B2
Application number	US-201415541659-A
Country	US
Kind code	B2
Filing date	Dec 29, 2014
Priority date	Dec 19, 2014
Publication date	Sep 17, 2019
Grant date	Sep 17, 2019

Abstract

An arrayed waveguide grating based hybrid integrated laser has an adjustable external cavity. The waveguide includes a semiconductor gain die and an optical waveguide chip. The optical waveguide chip includes an arrayed waveguide grating and an arrayed waveguide reflection-controllable component. A resonant cavity is formed by the output end reflection-controllable arrayed waveguide grating chip and the semiconductor gain die. An output wavelength of the laser can be adjusted by changing a driving condition of the reflection-controllable component. The output wavelength is determined by a center wavelength of each channel of the arrayed waveguide grating.

First claim

The invention claimed is:

1. An arrayed waveguide grating based hybrid integrated laser having adjustable external cavity, comprising:
an optical waveguide chip; and
a semiconductor gain die disposed downstream of the optical waveguide chip, wherein:
the optical waveguide chip includes an arrayed waveguide grating and an arrayed waveguide reflection-controllable component, the arrayed waveguide reflection-controllable component includes a plurality of controllable devices, and the arrayed waveguide grating optically connects the plurality of controllable devices to the semiconductor gain die;
two end surfaces of the semiconductor gain die are coated with a partial reflection film and an anti-reflection film respectively, the optical waveguide chip is positioned at the anti-reflection film side of the semiconductor gain die to form an external cavity of the external cavity adjustable laser, the partial reflection film of the semiconductor gain chip and the arrayed waveguide reflection-controllable component form the resonant cavity of the laser;
each of the plurality of the controllable devices is able to change an in-cavity loss of the resonant cavity or change reflection characteristic of the reflection end of the optical waveguide chip by adjusting external driving conditions, so as to implement wavelength tuning of the external cavity adjustable laser; and
wherein each of the controllable devices includes either:
(a) a controllable high attenuation device and a straight waveguide, wherein the controllable high attenuation device comprises an optical on/off switch, and an end surface of each straight waveguide is coated with a high reflection film, the high reflection film of each straight waveguide and the partial reflection film of the semiconductor gain chip form the resonant cavity of the laser, the respective optical on/off switches are controlled separately to be on to make the resonant cavity corresponding to respective wavelengths reach a threshold condition to output a laser beam, thereby obtaining the laser beam with the corresponding wavelength; or
(b) a straight waveguide and a Bragg grating, wherein each straight waveguide includes an end surface coated with an anti-reflection film, and each Bragg grating and the partial reflection film of the semiconductor gain chip form the resonant cavity of the laser, a center wavelength of each Bragg grating deviates from a center wavelength of the corresponding port of the arrayed waveguide grating to ensure that a signal of the center wavelength of the Bragg grating is unable to generate a laser output when no driving condition is implemented, and the center wavelength of the respective Bragg gratings are controlled separately to make the resonant cavities corresponding to respective wavelengths reach the threshold condition to output the laser, thereby obtaining the laser output of the corresponding wavelength.

2. The arrayed waveguide grating based hybrid integrated laser having adjustable external cavity of claim 1 , further comprising a coupling output circuit, an optical power detection device, and a control driving unit.

3. The arrayed waveguide grating based hybrid integrated laser having adjustable external cavity of claim 2 , wherein the coupling output circuit includes a collimation coupling lens, an optical isolator, and a output coupling lens, the collimation coupling lens collimates and couples a laser beam outputted from the semiconductor gain die to the optical isolator, the output coupling lens is connected to an output optical fiber to couple the outputted laser beam to the output optical fiber;
the optical power detection device includes a beam splitter and an optical detector, the beam splitter is provided between the optical isolator and the output coupling lens to split off a portion of the laser beam outputted from the optical isolator to the output coupling leans by a ratio and provide the split portion to the optical detector;
the control driving unit includes a control driving device in connection with the optical waveguide chip, the semiconductor gain die, and the optical detector.

4. The arrayed waveguide grating based hybrid integrated laser having adjustable external cavity of claim 1 , wherein the Bragg grating is fabricated by a phase mask process, the Bragg grating has a material thermo-optic effect, and the center wavelength of the Bragg grating is controlled by a heating element.

5. The arrayed waveguide grating based hybrid integrated laser having adjustable external cavity of claim 1 , wherein the arrayed waveguide grating comprises an a thermal silicon based arrayed waveguide grating, which has an output channel interval depending on the channel interval of the communication system in which it is applied.

6. The arrayed waveguide grating based hybrid integrated laser having adjustable external cavity of claim 1 , further comprising a semiconductor cooler and a thermal resistor, wherein phase of the outputted laser beam is controlled by adjusting current of the semiconductor gain die or changing temperature of the semiconductor cooler below the semiconductor gain die.

7. The arrayed waveguide grating based hybrid integrated laser having adjustable external cavity of claim 1 , wherein the straight waveguide is provided with a thermo-optic phasing element, and the phase of the outputted laser beam is controlled by the thermo-optic phasing element.

8. The arrayed waveguide grating based hybrid integrated laser having adjustable external cavity of claim 3 , wherein the optical detector feeds back a current photocurrent sample value to the control driving device, and the control driving device calculate a current output power according to a pre-calibrated relationship between the output power of the laser and the photocurrent of the optical detector, compare the current output power with a target optical power, and adjust the current of the semiconductor gain die to make the output power of the laser reach the target optical power.

Assignees

• Accelink Tech Co Ltd

Inventors

• Fu Yanfeng
• Qian Kun
• Zhang Di
• Tang Xuesheng
• Hu Shenglei
• Tang Yi
• Li Di
• Ma Weidong
• Hu Qianggao

Classifications

• H01S5/142

  which comprises an additional resonator · CPC title

• H01S3/137

  for stabilising of frequency · CPC title

• H01S3/106

  by controlling devices placed within the cavity ({H01S3/10076,} H01S3/13 take precedence) · CPC title

• H01S5/0287

  Facet reflectivity · CPC title

• G02B6/12014

  characterised by the wavefront splitting or combining section, e.g. grooves or optical elements in a slab waveguide · CPC title