CN112310805A

CN112310805A - Narrow-linewidth external cavity laser and optical module

Info

Publication number: CN112310805A
Application number: CN201910712122.6A
Authority: CN
Inventors: 涂文凯; 骆亮
Original assignee: Innolight Technology Suzhou Ltd
Current assignee: Innolight Technology Suzhou Ltd
Priority date: 2019-08-02
Filing date: 2019-08-02
Publication date: 2021-02-02

Abstract

The application discloses a narrow linewidth external cavity laser, which comprises a sealed shell, an external resonant cavity arranged in the sealed shell, a gain chip arranged in the external resonant cavity and a tunable wavelength selection element, wherein the gain chip is arranged in the external resonant cavity; the electrical interface of the sealed shell is used for transmitting electrical signals such as a driving signal, a wave selection signal, a cavity length control signal, a jitter control signal and the like; wherein the cavity length control signal adjusts the optical cavity length of the external resonant cavity by adjusting the gain chip to align the laser mode with the wavelength of the wavelength selective element; the dither control signal is used to control the optical cavity length of the external resonant cavity to dither to lock the center wavelength of the output beam. The cavity length control signal is acted on the gain chip, so that the number of elements in the external cavity is reduced, and on one hand, the packaging size can be greatly reduced, and the size is smaller; on the other hand, the external cavity insertion loss can be effectively reduced, the influence of the insertion loss on the laser power and the line width is further reduced, and the laser with more stable and narrower line width is output by matching with a laser mode capable of being finely adjusted.

Description

Narrow-linewidth external cavity laser and optical module

Technical Field

The application relates to the technical field of optical communication, in particular to a narrow-linewidth external cavity laser and an optical module.

Background

Coherent optical communication is an important technology for solving the problem of chromatic dispersion in long-distance transmission in the field of optical communication, a wavelength tunable laser is a core device of a coherent optical transmitter, and particularly, a tunable external cavity laser has a narrow linewidth characteristic, so that the chromatic dispersion problem in long-distance transmission is well solved.

Miniaturization of the package has been a trend of tunable laser, and it is required to be applicable to various optical modules in different package forms. The Chinese patent application 'small-sized packaged tunable laser component' (application number: 201410059069.1) discloses a miniaturized tunable laser, which comprises a shell with the volume less than 0.6 cubic centimeter, and a tunable semiconductor laser, a beam splitter, an optical isolator, a photodiode and a coupling optical system are sequentially arranged in the shell. The tunable semiconductor laser comprises a gain chip, a vernier tuning mechanism consisting of two filters and a cavity length actuator. With the higher integration of the device, the optical module is required to have a smaller volume, and thus the laser used as the core device of the coherent optical module is also required to have a smaller volume. The tunable laser assembly disclosed in the above patent application has a smaller volume, but in some more miniaturized optical modules, it is obvious that there is a need for smaller volume.

Disclosure of Invention

An object of the application is to provide a narrow linewidth external cavity laser and optical module, have advantages such as the encapsulation size is little, the external cavity insertion loss is little, laser linewidth is narrow.

In order to achieve one of the above objects, the present application provides a narrow linewidth external cavity laser, including a sealed housing provided with an optical interface and an electrical interface;

the tunable filter also comprises an external resonant cavity arranged in the sealed shell, and a gain chip and a tunable wavelength selection element which are arranged in the external resonant cavity;

the electrical interface is used for transmitting electrical signals, and the electrical signals comprise driving signals, wave selection signals, cavity length control signals and jitter control signals;

the driving signal drives the gain chip to emit light beams, and the light beams resonate in the external resonant cavity to generate a laser mode;

the wave selection signal tunes the wavelength selection element to select a required wavelength;

the cavity length control signal is used to adjust an optical cavity length of the external resonant cavity to align the lasing mode with a wavelength of the wavelength selective element;

the jitter control signal is used for controlling the optical cavity length of the external resonant cavity to generate jitter so as to lock the central wavelength of the output light beam;

the cavity length control signal adjusts an optical cavity length of the external resonant cavity by adjusting the gain chip.

As a further improvement of the embodiment, the cavity length control signal is superimposed on the bias current of the gain chip, and the optical length of the gain chip is changed by adjusting the bias current of the gain chip to adjust the optical cavity length of the external resonant cavity.

As a further improvement of the embodiment, a TEC is disposed in the sealed housing, and the gain chip is disposed on the TEC;

the cavity length control signal adjusts the optical length of the gain chip by controlling the temperature of the TEC so as to adjust the optical cavity length of the external resonant cavity.

As a further improvement of the embodiment, the jitter control signal is superimposed on the bias current of the gain chip, and the optical length of the gain chip is changed by adjusting the bias current of the gain chip to generate the optical jitter.

As a further improvement of the embodiment, the external cavity laser further includes an actuator on which one cavity surface of the external resonant cavity is provided;

the dither control signal dithers the facet on the actuator by controlling deformation of the actuator.

As a further improvement of the embodiment, the gain chip is disposed on the actuator, and one cavity surface of the external resonant cavity is disposed on an end surface of the gain chip remote from the wavelength selective element.

As a further improvement of the embodiment, the laser further includes a coupling lens, and the coupling lens is located on the output optical path of the external resonant cavity; the coupling lens comprises a plane close to the external resonant cavity and a spherical surface or an aspherical surface far away from the external resonant cavity; an output cavity surface of the external resonant cavity is disposed on the plane of the coupling lens, which is disposed on the actuator.

As a further improvement of the embodiment, the laser further includes an isolator, the isolator being located on the output optical path of the external resonant cavity; the output cavity surface of the external resonant cavity is arranged on the plane of the isolator close to the external resonant cavity; the isolator is disposed on the actuator.

As a further refinement of the embodiment, the actuator comprises one of a piezoelectric element, a MEMS or a linear motor.

As a further improvement of the embodiment, the external cavity laser further includes a cavity length dither element, and the cavity length dither element is disposed in the external resonant cavity;

the dither control signal optically dithers the external resonant cavity by controlling the cavity length dithering element.

As a further improvement of the embodiment, the cavity length dithering element includes one of an acousto-optic element, a magneto-optic element, an electro-optic element, or a liquid crystal component.

As a further improvement of the embodiment, the cavity length dither element is provided between the wavelength selective element and a cavity surface of the external resonant cavity;

the cavity length dither element comprises two opposite planes, and the cavity surface of the external resonant cavity is arranged on the plane of the cavity length dither element far away from the wavelength selection element.

As a further refinement of an embodiment, the volume of the sealed housing is less than or equal to 0.3 cubic centimeters.

The present application further provides an optical module comprising the external cavity laser of any of the embodiments described above.

The beneficial effect of this application: the cavity length control signal is acted on the gain chip, so that the number of elements in the external cavity is reduced, and on one hand, the packaging size can be greatly reduced, and the size is smaller; on the other hand, the external cavity insertion loss can be effectively reduced, the influence of the insertion loss on the laser power and the line width is further reduced, and the laser with more stable and narrower line width is output.

Drawings

FIG. 1 is a schematic diagram of a narrow linewidth external cavity laser package according to the present application;

FIG. 2 is a schematic diagram of a laser module in embodiment 1 of the external cavity laser of the present application;

FIG. 3 is a diagram showing the application of the cavity length control signal and the jitter control signal to the gain chip in embodiment 1;

FIG. 4 is a schematic diagram of TEC acted on by a cavity length control signal in example 1;

FIG. 5 is a diagram showing a gain chip to which only a cavity length control signal is applied in embodiment 2;

FIG. 6 is a diagram illustrating that only the dither control signal is applied to the gain chip in embodiment 2;

FIG. 7 is a schematic diagram showing that only the cavity length control signal is applied to the gain chip in embodiment 3;

FIG. 8 is a diagram illustrating that only the dither control signal is applied to the gain chip in embodiment 3;

FIG. 9 is a schematic diagram of a laser module in embodiment 4 of the external cavity laser of the present application;

FIG. 10 is a schematic view of another package for a narrow linewidth external cavity laser according to the present application;

FIG. 11 is a schematic diagram of an optical module according to the present application.

Detailed Description

The present application will now be described in detail with reference to specific embodiments thereof as illustrated in the accompanying drawings. These embodiments are not intended to limit the present application, and structural, methodological, or functional changes made by those skilled in the art according to these embodiments are included in the scope of the present application.

In the various illustrations of the present application, certain dimensions of structures or portions may be exaggerated relative to other structures or portions for ease of illustration and, thus, are provided to illustrate only the basic structure of the subject matter of the present application.

Also, terms used herein such as "upper," "above," "lower," "below," and the like, denote relative spatial positions of one element or feature with respect to another element or feature as illustrated in the figures for ease of description. The spatially relative positional terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary term "below" can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. When an element or layer is referred to as being "on," or "connected" to another element or layer, it can be directly on, connected to, or intervening elements or layers may be present.

The application provides a narrow linewidth external cavity laser with miniaturized package dimensions. As shown in fig. 1 and 2, the external cavity laser includes a hermetically sealed enclosure 100 and a laser assembly disposed within the hermetically sealed enclosure 100. The laser assembly includes an external cavity and a gain chip 310 and tunable wavelength selective element 320 disposed within the external cavity. The sealed housing 100 is provided with an optical interface 110 and an electrical interface 120, wherein the optical interface 110 is used for transmitting optical signals, and the electrical interface 120 is used for transmitting electrical signals. The electrical signals include a drive signal, a wave select signal, a cavity length control signal, and a dither control signal. When the laser works, a driving signal, such as a bias current of the gain chip 310, drives the gain chip 310 to emit a light beam, and the light beam resonates in the external resonant cavity to generate a laser mode; the wavelength selection signal tuning wavelength selection element 320 selects a desired wavelength, for example, in optical communication, for selecting a certain ITU standard wavelength required for optical communication. The cavity length control signal is used to adjust the optical cavity length of the external resonant cavity to align the lasing mode with the wavelength selected by the wavelength selective element 320; the dither control signal is used to control the optical cavity length of the external resonant cavity to dither to lock the center wavelength of the output beam.

One or two control signals of the cavity length control signal and the jitter control signal are used for adjusting the optical cavity length of the external resonant cavity or enabling the optical cavity length to jitter by adjusting the gain chip. The cavity length control signal is acted on the gain chip, so that the number of elements in the external cavity is reduced, and on one hand, the packaging size can be greatly reduced, and the size is smaller; on the other hand, the external cavity insertion loss can be effectively reduced, the influence of the insertion loss on the laser power and the line width is further reduced, and the laser with more stable and narrower line width is output. The following embodiments will explain in detail the specific structure of the laser module in the housing with reference to the drawings.

Example 1

As shown in fig. 1 to 3, the laser module disposed in the sealed housing 100 includes an external resonant cavity, a gain chip 310 and a tunable wavelength selection element 320 disposed in the external resonant cavity, a coupling lens 330 and an isolator 340 are further disposed in the sealed housing 100, the optical interface 110 of the sealed housing 100 is connected to the optical fiber 200, and laser output by the laser module is coupled into the optical fiber 200 through the coupling lens 330 and transmitted out of the housing 100 through the optical fiber 200. The optical fiber 200 includes a fiber stub 210 and a pigtail. The optical fiber head 210 includes a fixed sleeve, such as a glass sleeve, in which a capillary is disposed, and one end of the tail fiber is disposed in the capillary; the fixed sleeve of the fiber optic head 210 is disposed within the optical interface 110 of the housing 100. The optical fiber head omits a ceramic ferrule, and the tail fiber is directly fixed by the glass sleeve, so that the length of the optical fiber head is shortened, and the overall size of a device is reduced. Of course, in other embodiments, the optical interface 110 of the housing 100 may also be connected to a pluggable connector, not necessarily an optical fiber.

In this embodiment, a TEC (thermal Electric Cooler) 360 and a thermistor 380 are further disposed in the housing 100, and the gain chip 310, the wavelength selection element 320 and the coupling lens 330 are disposed on the TEC 360. The gain chip 310 is disposed on the TEC 360 via a chip substrate 370, the thermistor 380 is disposed on the chip substrate 370 near the gain chip 310 for feeding back the temperature of the gain chip 310, and the isolator 340 is disposed in the optical interface 110 of the housing 100. A first end face 311 of the gain chip 310, which is far away from the wavelength selection element 320, is plated with a high-reflection film to serve as a reflection cavity face of the external resonant cavity, and a second end face 312 of the gain chip 310, which is near to the wavelength selection element 320, is plated with an antireflection film; the coupling lens 330 includes a first plane 331 and a convex surface 332 on the optical path, the first plane 331 is close to the wavelength selective element 320, and is coated with a partial reflective film as the output cavity surface of the external resonant cavity, and the convex surface 332 is spherical or aspheric and is coated with an antireflection film. I.e. the first end face 311 of the gain chip 310 and the first plane 331 of the coupling lens 330 form two cavity faces of the external resonant cavity. In this embodiment, a collimating lens 350 is further disposed between the gain chip 310 and the wavelength selective element 320, the collimating lens 350 collimates the light beam emitted from the gain chip 310 and makes the light beam incident on the wavelength selective element 320, the wavelength selective element 320 selects a desired wavelength, so that the desired wavelength is competed by a mode in the external resonant cavity, and resonates in the cavity to generate laser light, and finally outputs a single-mode laser light with a narrow line width through the output cavity surface, and the coupling lens 330 focuses and couples the output laser light into the optical fiber 200, and outputs the laser light through the optical fiber 200. The isolator 340 disposed in the optical interface 110 isolates return light reflected by the end face of the optical fiber and the end faces on the external optical path, thereby preventing the return light from returning to the cavity and affecting the stability of the output laser.

The structure integrates two cavity surfaces of the external resonant cavity into one end of the gain chip and one end of the coupling lens respectively, so that optical elements in the cavity are effectively reduced, optical insertion loss in the cavity is reduced, the influence of the insertion loss on laser power and line width is reduced, and the cavity length of the external cavity is effectively shortened. The shorter the cavity length is, the larger the Free Spectral Range (FSR) of the laser mode (cavity film) of the intracavity resonance is, the more stable the output laser is, and the mode hopping is not easy, and in addition, the shorter the cavity length is, the smaller the laser package can be made, and then the isolator is integrated into the optical interface (or optical window) of the housing, and also can be integrated into the optical fiber head of the optical fiber, and the number of elements in the housing is less, and the housing can be made smaller. In this embodiment, the housing may be made to be less than or equal to 3 cubic centimeters, for example, a rectangular parallelepiped housing with a length of 10mm, a width of 5.8mm, and a height of 4.4mm, or smaller.

In this embodiment, as shown in fig. 3, the cavity length control signal and the jitter control signal are both superimposed on the bias current of the gain chip 310, and the optical length of the gain chip 310 is changed by adjusting the bias current of the gain chip 310 to adjust the optical cavity length of the external resonant cavity and to jitter the optical cavity length. The refractive index and temperature of the gain chip 310 change with the magnitude of the current applied thereto, the change in the refractive index of the gain chip 310 will cause the optical cavity length thereof to change, and the change in the temperature of the gain chip 310 will also cause the length thereof to change. In operation, the wavelength selection signal tunes the transmission spectrum of the wavelength selective element 320, switches it to a desired wavelength (channel), applies a cavity length control signal to the bias current of the gain chip 310 to adjust the cavity length of the external cavity to change the phase of the lasing mode, align the output lasing mode with the wavelength of the wavelength selective element 320, and applies a dither control signal to the bias current to dither the external cavity optical cavity length to lock the center wavelength of the output beam.

In other embodiments, as shown in FIG. 4, the cavity length control signal may also be applied to TEC 360 to adjust the temperature of TEC 360 to change the temperature of gain chip 310 to adjust the cavity length of the external resonant cavity, thereby changing the phase of the lasing mode to align the output lasing mode with the wavelength of wavelength selective element 320. The gain chip 310 is disposed on the TEC 360 through a chip substrate 370, and the chip substrate 370 is provided with a thermistor 380 for feeding back the temperature of the gain chip 310, and forms a closed-loop feedback system together with the TEC 360 to control the temperature of the gain chip 310.

One or two control signals of the cavity length control signal and the jitter control signal are applied to the gain chip, the optical cavity length of the external resonant cavity is adjusted or the optical cavity length is jittered by adjusting the gain chip, the adjusting speed is high, no additional adjusting element is needed, the number of elements in the external cavity is reduced, and the packaging size is further reduced.

Example 2

As shown in fig. 5, unlike embodiment 1, the laser module further includes an actuator 390, one facet of the external cavity is disposed on the actuator 390, the jitter control signal is applied to the actuator 390, and the actuator 390 is adjusted to jitter the facet of the external cavity thereon to generate a jitter in the output optical signal, so as to lock the center wavelength of the output optical beam. Here, the actuator may be a piezoelectric element, an acousto-optic element, an electro-optic element, a liquid crystal assembly, a MEMS or other linear motor, or the like.

In this embodiment, the positions of the isolator 340 and the coupling lens 330 are different from those in embodiment 1, the isolator 340 and the coupling lens 330 are interchanged, the isolator 340 is disposed behind the wavelength selective element 320, and the coupling lens 330 is integrated into the optical interface of the sealed housing. The separator 340 includes two opposing planes: the second plane 341 and the third plane 342 are located on the output optical path of the external cavity, and the output cavity surface of the external cavity is located on the second plane 341 of the isolator 340 near the wavelength selective element 320. The isolator 340 is disposed on the actuator 390, such as piezoelectric ceramic (PZT), and a jitter control signal is applied to the PZT to control the deformation of the PZT to adjust the position of the output cavity surface disposed on the isolator 340, so as to enable the output cavity surface of the external resonant cavity to jitter, thereby enabling the output optical signal to generate jitter and facilitating locking the central wavelength of the output optical beam.

Of course, the positions of the coupling lens and the isolator may also be the same as that in embodiment 1, the coupling lens is disposed on the actuator, the jitter control signal is applied to the actuator, and the position of the output cavity surface disposed on the coupling lens is adjusted by controlling the deformation of the actuator, so that the output cavity surface of the external resonant cavity is jittered, thereby generating jitter on the output optical signal and facilitating locking the center wavelength of the output optical beam.

In other embodiments, an actuator, such as a piezoelectric element with good thermal conductivity, an acousto-optic element, or an electro-optic element, such as a piezoelectric ceramic (PZT), may also be added below the gain chip, the gain chip and the collimating lens are both placed on the actuator, the actuator is then placed on the TEC, the dither control signal is applied to the actuator, and the position of the cavity surface on the gain chip is adjusted by controlling the deformation of the actuator, so that the cavity surface of the external resonant cavity is dithered, thereby dithering the output optical signal and facilitating the locking of the center wavelength of the output beam.

Of course, as shown in fig. 6, the dither control signal may be applied to the bias current of the gain chip 310, and the cavity length control signal may be applied to the actuator 390 (e.g., piezoelectric ceramic, etc.). The elements in fig. 6 are the same as in fig. 5, except that the cavity length control signal and the dither control signal are controlled in a different manner. In operation, the wavelength selection signal tunes the transmission spectrum of the wavelength selective element 320, switches it to a desired wavelength (channel), applies a cavity length control signal to the actuator 390, controls the deformation of the actuator 390 via the cavity length control signal to change the position of the output cavity surface (the second plane 341 of the isolator 340) thereon to adjust the cavity length of the external resonant cavity, thereby changing the phase of the laser mode, aligning the output laser mode with the wavelength of the wavelength selective element 320, and applies a dither control signal to the bias current of the gain chip 310 to dither the optical cavity length of the external resonant cavity to lock the center wavelength of the output beam.

Example 3

As shown in fig. 7, unlike embodiment 2, in this embodiment, the laser module does not have an actuator, but a cavity length dither element 390a is provided in the external resonant cavity, the cavity surface of the external resonant cavity may be provided on the isolator 340, or on a fourth plane 391a of the cavity length dither element 390a away from the wavelength selective element 320, and the isolator 340 and the coupling lens 330 are provided behind the output cavity surface of the external resonant cavity. In this embodiment, the output facet of the external cavity is disposed on a fourth plane 391a of the cavity length dithering element 390a remote from the wavelength selective element 320, and the isolator 340 and the coupling lens 330 are disposed behind the cavity length dithering element 390. A dither control signal is applied to the cavity length dither element 390a to dither the external resonant cavity by controlling the cavity length dither element 390a to dither the output optical signal to facilitate locking the center wavelength of the output beam. Here, the cavity length dither element 390a may be one of an acousto-optic element, a magneto-optic element, an electro-optic element, or a liquid crystal module, and has a fast response speed to a dither control signal, which is beneficial to improving the efficiency of wavelength locking and reducing power consumption. In operation, a cavity length control signal applied to the bias current of gain chip 310 changes the refractive index and temperature of gain chip 310 by adjusting the bias current to change the cavity length of the external resonant cavity, thereby changing the phase of the lasing mode to align the output lasing mode with the wavelength selected by wavelength selective element 320, and a dither control signal is applied to cavity length dither element 390a to dither the optical cavity length of the external resonant cavity to lock the center wavelength of the output beam.

In other embodiments, as shown in FIG. 8, the cavity length dithering element may be replaced with a cavity length adjusting element 390b, and the cavity length control signal may be applied to the cavity length adjusting element 390b to change the optical cavity length of the external cavity by controlling the cavity length adjusting element 390 b. The dither control signal is applied to the bias current of the gain chip 310, and the refractive index and the temperature of the gain chip 310 are changed by adjusting the bias current, so that the external cavity length of the external cavity is dithered to lock the center wavelength of the output beam. Here, the cavity length adjusting element 390b includes one of a thermo-optical element, an acousto-optical element, a magneto-optical element, an electro-optical element, or a liquid crystal component. The cavity surface of the external cavity may be provided on the isolator 340 or on a fifth plane 391b of the cavity length adjusting element 390b remote from the wavelength selective element 320. In this embodiment, the cavity length adjusting element 390b is disposed between the wavelength selective element 320 and the cavity surface of the external resonant cavity, the cavity length adjusting element 390b includes two opposite planes, and the cavity surface of the external resonant cavity is disposed on a fifth plane 391b of the cavity length adjusting element 390b away from the wavelength selective element 320. In operation, a cavity length control signal is applied to the cavity length adjustment element 390b to change the cavity length of the external resonant cavity, thereby changing the phase of the lasing mode, aligning the output lasing mode with the wavelength selected by the wavelength selection element 320, and applying a dither control signal to the bias current of the gain chip 310 to change the refractive index and temperature of the gain chip 310 by adjusting the bias current, thereby dithering the optical cavity length of the external resonant cavity to lock the center wavelength of the output beam.

Example 4

As shown in fig. 9, unlike embodiments 1 and 2, in this embodiment, a partially reflective film is plated on a first end surface 311 of the gain chip 310 away from the wavelength selective element 320 as an output facet of the external cavity, and a highly reflective film is plated on a sixth plane 322 of the wavelength selective element 320 away from the gain chip 310 as a reflection facet of the external cavity. The coupling lens 330, the isolator 340 and the optical interface 110 of the housing are located on the optical path of the output facet output of the gain chip 310.

In this embodiment, the cavity length control signal and the dither control signal may both be applied to the bias current of the gain chip 310, or the cavity length control signal may also be applied to the TEC 360 for changing the refractive index and/or temperature of the gain chip 310 to adjust the cavity length of the external cavity to change the phase of the lasing mode and align the output lasing mode with the wavelength of the wavelength selective element, the dither control signal dithering the external cavity optical cavity length to lock the center wavelength of the output beam.

Alternatively, an actuator 390, such as a piezoelectric ceramic, may be added under the gain chip 310, and a dither control signal is applied to the bias current of the gain chip 310 and a cavity length control signal is applied to the piezoelectric ceramic, so as to adjust the position of the cavity surface disposed on the gain chip 310 by changing the deformation of the piezoelectric ceramic to adjust the cavity length of the external resonant cavity, thereby changing the phase of the laser mode and aligning the output laser mode with the wavelength of the wavelength selective element 320. Or vice versa, the cavity length control signal is applied to the bias current of the gain chip 310 and the dither control signal is applied to the piezoelectric ceramic.

Of course, in other embodiments, an actuator may be added below the wavelength selective element 320, a dither control signal is applied to the bias current of the gain chip 310, a cavity length control signal is applied to the actuator, and the position of the cavity surface disposed on the wavelength selective element 320 is adjusted by controlling the actuator to adjust the cavity length of the external resonant cavity, thereby changing the phase of the laser mode and aligning the output laser mode with the wavelength of the wavelength selective element. Or conversely, the cavity length control signal is applied to the bias current of the gain chip 310 or to the TEC 360, and the dither control signal is applied to an actuator under the wavelength selective element 320, which is controlled to dither the position of the wavelength selective element 320 to optically dither the cavity surface of the external resonant cavity to output a dithered optical signal to lock the center wavelength of the output beam.

In the above embodiments, as shown in fig. 1, the electrical interface 120 of the sealed housing 100 may be disposed on an end surface of the sealed housing 100 opposite to the optical interface 110, or as shown in fig. 10, the electrical interface 120 may be disposed on a side surface of the sealed housing 100. The electrical interface 120 is disposed on the side of the sealed housing 100, so that the wiring in the sealed housing can be omitted, the space for wiring in the sealed housing can be reduced, and the volume of the sealed housing can be further reduced. The cavity surface of the external resonant cavity can also be an independent total reflection cavity mirror and/or a partial reflection cavity mirror which are respectively arranged at one side of the gain chip far away from the wavelength selection element and one side of the wavelength selection element far away from the gain chip.

The wavelength selective element 320 in the above embodiments may be a single tunable filter element as shown in fig. 2-4 and 9, a vernier system composed of two filter elements as shown in fig. 5-8, or a wavelength selective element with other structure.

Example 5

As shown in fig. 11, the present application provides an optical module, which includes a module housing 500, a circuit board 600, a silicon optical chip 400, and a narrow linewidth laser. Here, the narrow linewidth laser may adopt the narrow linewidth external cavity laser of any of the above embodiments, and a feedback component of the narrow linewidth external cavity laser is further integrated on the silicon optical chip 400, where the feedback component includes a light splitting element and a light detector (MPD) for feeding back the optical power and the central wavelength output by the external cavity laser. Of course, in other embodiments, the feedback assembly may also employ a combination of a split detector or other form of splitting element and MPD. The miniaturized narrow linewidth external cavity laser of this application that this optical module adopted, the size of module can be done littleer, and the integrated level is higher, has more stable narrow linewidth single mode laser output moreover.

In other embodiments, the housing of the optical module may also adopt a package housing with other structures, and is not limited to the housing structure shown in fig. 11. In this embodiment, the optical modulator and the optical receiver are integrated on a silicon optical chip, and in other embodiments, the optical modulator and/or the optical receiver may be independent devices in free space.

The narrow-linewidth external cavity laser can provide a high-power narrow-linewidth light source for a coherent optical module, the output optical power can be higher than 12dBm, the linewidth can be smaller than or equal to 100kHz, the power is higher than that of a DFB laser, the linewidth is narrower than that of the DFB laser, and the narrow-linewidth external cavity laser is particularly suitable for an optical module modulated by silicon light and is certainly suitable for other optical modules.

The above list of details is only for the concrete description of the feasible embodiments of the present application, they are not intended to limit the scope of the present application, and all equivalent embodiments or modifications that do not depart from the technical spirit of the present application are intended to be included within the scope of the present application.

Claims

1. A narrow linewidth external cavity laser comprises a sealed shell, wherein the sealed shell is provided with an optical interface and an electrical interface; the method is characterized in that:

2. The external cavity laser of claim 1, wherein:

the cavity length control signal is superposed on the bias current of the gain chip, and the optical length of the gain chip is changed by adjusting the bias current of the gain chip so as to adjust the optical cavity length of the external resonant cavity.

3. The external cavity laser of claim 1, wherein:

a TEC is arranged in the sealed shell, and the gain chip is arranged on the TEC;

4. An external cavity laser as claimed in claim 2 or 3, wherein: the jitter control signal is superposed on the bias current of the gain chip, and the optical length of the gain chip is changed by adjusting the bias current of the gain chip so as to generate optical jitter.

5. An external cavity laser as claimed in claim 2 or 3, wherein:

the external cavity laser further comprises an actuator, and one cavity surface of the external resonant cavity is arranged on the actuator; the dither control signal dithers the facet on the actuator by controlling deformation of the actuator.

6. The external cavity laser of claim 5, wherein: the gain chip is disposed on the actuator, and one cavity surface of the external resonant cavity is disposed on an end surface of the gain chip remote from the wavelength selective element.

7. The external cavity laser of claim 5, wherein:

the laser also comprises a coupling lens, and the coupling lens is positioned on an output optical path of the external resonant cavity; the coupling lens comprises a plane close to the external resonant cavity and a spherical surface or an aspherical surface far away from the external resonant cavity; an output cavity surface of the external resonant cavity is disposed on the plane of the coupling lens, which is disposed on the actuator.

8. The external cavity laser of claim 5, wherein:

the laser also comprises an isolator, wherein the isolator is positioned on an output optical path of the external resonant cavity; the output cavity surface of the external resonant cavity is arranged on the plane of the isolator close to the external resonant cavity; the isolator is disposed on the actuator.

9. An external cavity laser according to any of claims 5 to 8, wherein: the actuator comprises one of a piezoelectric element, a MEMS, or a linear motor.

10. An external cavity laser as claimed in claim 2 or 3, wherein:

the external cavity laser also comprises a cavity length jitter element which is arranged in the external resonant cavity;

11. The external cavity laser of claim 10, wherein: the cavity length dithering element comprises one of an acousto-optic element, a magneto-optic element, an electro-optic element or a liquid crystal component.

12. The external cavity laser of claim 10, wherein: the cavity length dithering element is arranged between the wavelength selection element and the cavity surface of the external resonant cavity;

13. The external cavity laser of claim 1, wherein: the volume of the sealed housing is less than or equal to 0.3 cubic centimeters.

14. An optical module, characterized in that: comprising an external cavity laser as claimed in any one of claims 1 to 13.