WO2009152658A1

WO2009152658A1 - Tunable laser module and controlling method thereof

Info

Publication number: WO2009152658A1
Application number: PCT/CN2008/071362
Authority: WO
Inventors: 薛江
Original assignee: 中兴通讯股份有限公司
Priority date: 2008-06-19
Filing date: 2008-06-19
Publication date: 2009-12-23
Also published as: CN102017473A

Abstract

A tunable laser module and the controlling method thereof are disclosed, wherein the said tunable laser module comprises a distributed feedback (DFB) laser, an automatic optical power control circuit, a driver control circuit, an automatic temperature control circuit and a cut-off control and performance detection circuit, and the DFB laser is electrically connected with the said circuits; the tunable laser module also comprises a Bragg voltage control circuit electrically connected with the DFB laser. Compared with other tunable lasers, laser in the present invention is provided with a wider tunable range.

Description

Tunable laser module and control method thereof

TECHNICAL FIELD The present invention relates to the field of digital optical fiber transmission systems, and in particular, to a tunable laser module and a control method thereof. BACKGROUND With the continuous development of optical communication technologies, optical transmitting modules and optical receiving modules have been more and more widely applied to optical transmission systems, and function as optical-electrical, electro-optical conversion. The performance of the light emitting module and the light receiving module has an important influence on the optical transmission system specifications. The telecommunication device passes the electrical signal to the optical transmitting module, and the optical transmitting module modulates the electrical signal into an optical signal output by the laser, thereby realizing the transmission of the signal in the optical domain. Medium and long-distance optical transmission systems generally use a refrigerated electro-absorption laser, and the operating wavelength of the laser must meet the specific wavelength requirements of the minimum channel spacing of 100 GHz for G.652/G.655 fiber specified in ITU-T G. . Specifically, the optical transmitting module generally includes: a wavelength tuning circuit for switching between different modes of the laser, that is, a wavelength tunable function; an automatic power control circuit (APC) for stabilizing the laser transmitting light Power, providing a monitoring value related to the laser output optical power and the bias current of the laser; the driver control circuit modulates the input electrical signal (including the differential data signal and the differential clock signal) into an optical signal output by the laser to realize the electrical signal To the conversion of the optical signal, the extinction ratio of the laser output optical signal is guaranteed to be stable; the automatic temperature control circuit (ATC) is used to stabilize the temperature of the laser die and stabilize the wavelength of the light, and to provide a laser on the other hand. The monitoring value of the die temperature and the temperature limit alarm signal; the shutdown control and performance detection circuit. In the process of implementing the technical solution of the present invention, the inventors have found that: the conventional laser wavelength tuning by the die temperature can be tuned to a narrow range, usually only covers C wavelength 100G interval 4 wavelengths; and the number of spare parts in the transmission system is relatively More, higher cost. SUMMARY OF THE INVENTION The present invention has been made in view of the problem that a conventional tunable range of a laser that is wavelength-tuned by a die temperature is narrow in the related art, and the present invention is directed to provide a tunable laser module and a control method thereof. To solve the above problems. To this end, in accordance with one aspect of the present invention, a tunable laser module is provided. The tunable laser module according to the embodiment of the present invention includes a distributed feedback laser, an automatic optical power control circuit, a driver control circuit, an automatic temperature control circuit, a turn-off control, and a performance detection circuit, and the distributed feedback laser is electrically connected to each circuit; The tuned laser module also includes a Bragg voltage control circuit electrically coupled to the distributed feedback laser. Preferably, the Bragg voltage control circuit is provided with a digital-to-analog converter that switches wavelengths of light. Preferably, the above-mentioned automatic optical power control circuit is configured with a first potentiometer for adjusting the power of the optical signal of the distributed feedback laser; and a second potentiometer for adjusting the extinction ratio of the optical signal of the distributed feedback laser is arranged in the driver control circuit; A third potentiometer is provided in the temperature control circuit for adjusting the wavelength of the light of the distributed feedback laser. According to one aspect of the invention, a method of controlling a tunable laser module is provided. The control method of the tunable laser module according to the embodiment of the present invention includes: writing a default value to the driver control circuit; determining the third potentiometer of the automatic temperature control circuit corresponding to the optical wavelength channel according to the index of the distributed feedback laser Value, and write the determined value to the third potentiometer; adjust the value of the digital-to-analog converter in the Bragg voltage control circuit to adjust the wavelength of the light to the corresponding grid, and maximize the side mode suppression ratio of the optical wavelength Adjusting the third potentiometer in the automatic temperature control circuit to adjust the wavelength of the light to a predetermined range; adjusting the first potentiometer of the automatic optical power control circuit to adjust the output optical signal power of the distributed feedback laser. Preferably, the side mode suppression ratio of the optical wavelength is maximized to be: after the wavelength deviation is required to be within a range of ±3 GHz, the side mode suppression ratio of the wavelength of the distributed feedback laser is tested, and the digital-to-analog converter of the Bragg voltage control circuit is adjusted. The value of the side mode is maximized. The above technical solution has the following advantages or advantages: The tunable laser module and the control method thereof provided by the present invention have a wider tunable range than other tunable modules. Other features and advantages of the invention will be set forth in the description which follows, and The objectives and other advantages of the invention will be realized and attained by the <RTI The drawings are intended to provide a further understanding of the invention, and are intended to be a part of the description of the invention. In the drawings: FIG. 1 is a schematic block diagram of a tunable laser module according to an embodiment of the present invention; FIG. 2 is a schematic block diagram of a tunable laser module according to an embodiment of the present invention; FIG. 3 is an embodiment of the present invention. Flow chart of control method for tunable laser module. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the present invention are described with reference to the accompanying drawings. Device Embodiment According to the embodiment of the present invention, a tunable laser module is first provided. In this embodiment, a distributed feedback (Distributed Feed Back, DFB for short) laser is used as a core component. 1 is a block diagram showing a schematic structure of a tunable laser module in accordance with an embodiment of the present invention. As shown in FIG. 1, a tunable laser module according to an embodiment of the present invention includes a DFB laser 1, an APC circuit 2, a driver control circuit 3, an ATC circuit 4, and a shutdown control and performance detecting circuit 6, and also includes a DFB. The Bragg voltage control circuit 5 to which the laser 1 is electrically connected, wherein the DFB laser 1 is electrically connected to each of the above-described circuits. 2 is a schematic block diagram of a tunable laser module in accordance with an embodiment of the present invention, and details of the various components described above are further described below with reference to FIG. A digital to analog converter (DAC) for wavelength switching of light is disposed in the Bragg voltage control circuit 5. In addition, a first potentiometer RA1 for adjusting the optical signal power of the DFB laser 1 is disposed in the APC circuit 2; a second potentiometer RA2 for adjusting the extinction ratio of the optical signal of the DFB laser 1 is disposed in the driver control circuit 3; A third potentiometer RA3 for stabilizing the die temperature of the DFB laser 1 and thereby stabilizing the optical wavelength of the DFB laser 1 is disposed in the ATC circuit 4.

The DFB laser 1 has: a Vbrag port connected to the Bragg voltage control circuit; a thermistor (RT) port and a semiconductor cooler (TEC) port connected to the ATC circuit; and a port connected to the high speed driver in the driver control circuit; The port to which the APC circuit is connected; the optical signal output port. DFB lasers also include optical isolators and the like, which are not mentioned here. In addition, the ATC circuit, the driver control circuit, the shutdown control circuit and the APC circuit have a serial electrical connection, and the tunable laser module further has an external serial interface. The shutdown control circuit has clock regeneration, laser shutdown, and module in-position identification. Method Embodiments According to an embodiment of the present invention, a control method of a tunable laser module is provided. 3 is a flowchart of a control method of a tunable laser module according to an embodiment of the present invention. As shown in FIG. 3, a control method of a tunable laser module according to an embodiment of the present invention includes:

S302. Write a default value to the driver control circuit;

S304. Determine a value of the third potentiometer of the automatic temperature control circuit corresponding to the optical wavelength channel according to the index of the distributed feedback laser, and write the determined value to the third potentiometer;

S306. Adjusting the value of the digital-to-analog converter in the Bragg voltage control circuit to adjust the optical wavelength to the corresponding grid, and maximizing the side mode suppression ratio of the optical wavelength;

S308. Adjust a third potentiometer in the automatic temperature control circuit to adjust the wavelength of the light to a predetermined range;

S310. Adjust a first potentiometer of the automatic optical power control circuit to adjust the output optical signal power of the distributed feedback laser. The following explains the above control method:

In S302, as a precondition for the normal operation of the DFB laser, it is necessary to write default values for each potentiometer, control eye intersection, and bias voltage in the driver control circuit. Here, the driver control circuit mainly plays amplifying power. The role of the signal. In S304, the value of the digital potentiometer RA3 of the ATC circuit corresponding to each optical wavelength channel is calculated according to the DFB laser index book, and the determined value is written into the RA3 by the host computer software.

In S306, the wavelength meter is observed, and the value of the DAC of the Bragg voltage control circuit is repeatedly adjusted to adjust the wavelength of the light to the corresponding ITU grid; after the wavelength deviation is within the range of ±3 GHz, the side mode suppression ratio of the laser light wavelength is tested. , adjust the DAC value of the Bragg voltage circuit again, and require the side touch suppression ratio to reach the maximum.

In S308, since the optical wavelength adjustment process of step S206 causes a small deviation of the optical wavelength, it is necessary to adjust the RA3 in the automatic temperature control circuit again to re-adjust the optical wavelength to the required range.

In S310, RA1 of the APC circuit is adjusted to adjust the output optical signal power of the DFB laser. Through the above operation, the parameter adjustment of one optical wavelength channel of the tunable laser can be completed. After that, the parameters involved in the above control method can be written into the electrically erasable programmable read only memory (EEPROM) by calibration, and all the values corresponding to the optical wavelength channels are recorded. In summary, the technical solution provided by the embodiments of the present invention has the following advantages or beneficial effects: The tunable laser module provided by the present invention has a wider tunable range by adding a Bragg voltage control circuit, and covers a C-band 100G interval of 16 Wavelength, while the traditional wavelength-tuned lasers relying on the die temperature can only cover C-band 100G interval 4 wavelengths; due to the use of micro-control unit and digital adjustment circuit, the tunable laser module parameters adjustment and performance detection Digitized, in this way, the tuning function of the laser can be conveniently realized by using the micro control unit software program; because the module covers a wider wavelength, the number of spare parts in the transmission system is greatly reduced, which indirectly reduces the cost of the transmission system; The production and debugging process of the laser module is easy to automate, which can effectively improve production efficiency and directly reduce production costs. The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

A tunable laser module, comprising a distributed feedback laser, an automatic optical power control circuit, a driver control circuit, an automatic temperature control circuit, a shutdown control, and a performance detection circuit, wherein the distributed feedback laser is electrically connected to the respective circuits The tunable laser further includes a Bragg voltage control circuit electrically coupled to the distributed feedback laser. The module according to claim 1, wherein said Bragg voltage control circuit is provided with a digital-to-analog converter that switches wavelengths of light. The module of claim 1 wherein:

a first potentiometer configured to adjust an optical signal power of the distributed feedback laser is disposed in the automatic optical power control circuit;

Configuring, in the driver control circuit, a second potentiometer for adjusting an extinction ratio of the optical signal of the distributed feedback laser;

A third potentiometer for adjusting the optical wavelength of the distributed feedback laser is disposed in the automatic temperature control circuit. A control method for a tunable laser module, comprising:

Write default values to the drive control circuit;

Determining the value of the third potentiometer of the automatic temperature control circuit corresponding to the optical wavelength channel according to the index of the distributed feedback laser, and writing the determined value to the third potentiometer;

By adjusting the value of the digital-to-analog converter in the Bragg voltage control circuit, the wavelength of the light is adjusted to the corresponding grid, and the side mode suppression ratio of the optical wavelength is maximized;

Adjusting the third potentiometer in the automatic temperature control circuit to adjust the wavelength of the light to a predetermined range;

The first potentiometer of the automatic optical power control circuit is adjusted to adjust the output optical signal power of the distributed feedback laser.

1

The method according to claim 4, wherein the maximum mode suppression ratio of the wavelength of the light is:

After the wavelength deviation is required to be within a range of ±3 GHz, the side mode suppression ratio of the wavelength of the distributed feedback laser is tested, and the value of the digital-to-analog converter of the Bragg voltage control circuit is adjusted such that the side mode suppression ratio is maximized .

2