Optical module capable of controlling wavelength of laser to be constant

Abstract

The utility model relates to the technical field of optical modules, in particular to an optical module capable of controlling the wavelength of a laser to be constant. Which comprises a laser, a ceramic substrate, a TEC and at least two first thermistors, the first thermistors and the laser are fixed on the ceramic substrate through elargol, the ceramic substrate is fixed on a cold surface of the TEC, the laser is arranged in a BOX or TO, and the device is characterized by further comprising a second thermistor which is arranged in the BOX or TO and in an area outside the TEC, and the second thermistor is used for monitoring the temperature of gas in the cavity. According to the scheme, the extra thermistor is placed in the BOX or TO and in the area outside the TEC, the temperature of the laser can be controlled more accurately, and constant control over the wavelength is achieved. In an actual test, the fluctuation is within a range of + / -0.01 nm, the yield and the performance of the optical module are improved, and the transmission stability of a DWDM optical module system is optimized.

Description

Technical Field

[0001] This utility model relates to the field of optical module technology, specifically to an optical module that can control the wavelength of a laser to be constant. Background Technology

[0002] In optical module design, the laser is a crucial component. Due to the characteristics of lasers, their wavelength varies with temperature. For DWDM optical modules, wavelength control is essential. DWDM stands for Dense Wavelength Division Multiplexing. This is a highly efficient method for transmitting data in optical fiber by multiplexing multiple optical signals of different wavelengths onto a single fiber. DWDM technology utilizes the wavelength characteristics of light, allowing multiple independent optical signals to be transmitted simultaneously on a single fiber, each occupying a different wavelength channel. This significantly increases the transmission capacity of the fiber without requiring additional physical fibers. The wavelength spacing in DWDM is typically only 0.4nm or 0.8nm. Currently, wavelength control is mainly achieved by using TEC (Temperature Controlled Temperature) to control the laser temperature.

[0003] In practical applications, since wavelength cannot be directly measured, temperature is typically used as feedback to adjust the TEC (Dielectric Temperature Coefficient). Temperature is usually collected and fed back using an NTC (Natural Temperature Coefficient) thermistor. However, in actual applications, although the thermistor and laser are on the same substrate, the laser's surface is exposed to air, resulting in a certain temperature discrepancy between the laser's actual temperature and the substrate temperature. Therefore, while the TEC maintains a constant temperature, the laser is not actually at a constant temperature, and the wavelength will still fluctuate, potentially exceeding 0.4 nm.

[0004] In addition, since DWDM uses a wavelength range of 1470nm~1625nm, it is prone to chirping. Controlling the wavelength to be constant can reduce the impact of chirping and improve the stability of long-distance transmission.

[0005] Therefore, based on the above problems, there is an urgent need for an optical module that can reduce chirp and improve the stability of long-distance transmission. Utility Model Content

[0006] Current controllable lasers are not kept at a constant temperature, and their wavelengths still fluctuate, potentially exceeding 0.4 nm, which can easily cause chirping. This application provides an optical module that can control the laser wavelength to a constant state to solve the above problems.

[0007] To achieve the above objectives, this utility model provides the following technical solution:

[0008] This application discloses an optical module capable of controlling the wavelength of a laser to a constant, comprising: a laser, a ceramic substrate, a TEC (thermoelectric control unit), and at least two first thermistors. The first thermistors and the laser are fixed to the ceramic substrate with silver paste, and the ceramic substrate is then fixed to the cold surface of the TEC. The laser is disposed inside a BOX or TO (thermoelectric control unit). The module is characterized by further comprising:

[0009] The second thermistor is located inside the BOX or TO, outside the TEC area, and is used to monitor the temperature of the gas inside the cavity.

[0010] Optionally, the laser is a DWDM laser with a wavelength range of 1470nm-1625nm.

[0011] Optionally, it also includes an MCU, which is used to measure the resistance signal of the thermistor, calculate the target temperature of the TEC according to a preset linear relationship, and adjust the TEC to make the laser temperature reach the target temperature.

[0012] Optionally, the linear relationship is T1=k T2+b, where T1 is the target temperature of TEC, T2 is the cavity gas temperature monitored by the second thermistor, and k and b are constants obtained through statistical analysis of multiple module tests.

[0013] Optionally, the value ranges of k and b are dynamically calibrated at three points: room temperature, high temperature, and low temperature.

[0014] Optionally, the MCU reads the resistance value of the second thermistor in real time during operation, calculates the temperature value of T2, calculates the target value of T1 based on the linear relationship, and adjusts the TEC to make T1 reach the target value, thereby accurately controlling the laser wavelength.

[0015] Technical effects:

[0016] By employing the technical solution described in this invention, an additional thermistor can be placed inside the BOX or TO module, outside the TEC area, to more precisely control the laser temperature and achieve constant wavelength control. In actual testing, the wavelength remained stable within the module's operating range (-35℃~85℃), with fluctuations within ±0.01nm, improving the yield and performance of the optical module and optimizing the transmission stability of the DWDM system. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the overall structure of the optical module that allows for constant control of the laser wavelength in this application.

[0019] In the picture:

[0020] 1. Laser; 2. Ceramic substrate; 3. TEC; 4. First thermistor; 5. BOX or TO; 6. Second thermistor. Detailed Implementation

[0021] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0022] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0023] Please see Figure 1 Traditional optical modules rely solely on a single thermistor to monitor the temperature of the ceramic substrate, failing to detect the temperature gradient of the gas inside the laser cavity (BOX / TO). This leads to a discrepancy between the actual laser temperature and the monitored value, resulting in insufficient wavelength control accuracy. Therefore, this application discloses an optical module capable of controlling a constant laser wavelength, comprising: a laser, a ceramic substrate, a TEC (thermoelectric control unit), and at least two first thermistors. The first thermistors and the laser are fixed to the ceramic substrate with silver paste, and the ceramic substrate is then fixed to the cold surface of the TEC. The laser is disposed inside the BOX or TO. The module further comprises:

[0024] The second thermistor is located inside the BOX or TO, outside the TEC area, and is used to monitor the temperature of the gas inside the cavity.

[0025] It is worth mentioning that this application adds a second thermistor, which is located inside the cavity outside the TEC, to directly monitor the temperature of the gas inside the cavity. This can eliminate the temperature transfer lag between the substrate and the cavity, improve the accuracy of the laser temperature feedback, and lay a structural foundation for precise temperature control.

[0026] Because general-purpose lasers have a wide wavelength range, they cannot meet the strict wavelength matching requirements of DWDM systems, easily leading to inter-channel crosstalk. Therefore, the laser used is a DWDM laser with a wavelength range of 1470nm-1625nm. It is worth noting that this embodiment ensures wavelength compatibility between the optical module and the DWDM system by limiting the laser to a DWDM-specific type and wavelength range, reducing channel interference caused by wavelength offset.

[0027] Traditional temperature control schemes rely on a fixed threshold to adjust the TEC power, which cannot dynamically respond to changes in the cavity ambient temperature, leading to temperature control delay and overshoot. Therefore, an MCU is also included. The MCU measures the resistance signal of the thermistor, calculates the target temperature of the TEC according to a preset linear relationship, and adjusts the TEC to bring the laser temperature to the target temperature. It is worth mentioning that this embodiment introduces an MCU and a preset linear relationship (T1=k...) T2+b) dynamically correlates the cavity gas temperature (T2) with the TEC target temperature (T1), enabling closed-loop control logic and improving temperature control response speed and accuracy.

[0028] Traditional linear relationship parameters (k, b) relying solely on theoretical calculations are prone to control deviations due to process variations or device aging. Therefore, the proposed linear relationship is T1=k. T2+b, where T1 is the target temperature of the TEC, T2 is the gas temperature inside the cavity monitored by the second thermistor, and k and b are constants obtained through statistical analysis of multiple module tests. It is worth noting that this embodiment determines the values ​​of k and b through statistical analysis of multiple module tests, avoiding the influence of individual differences, enhancing the universality and reliability of the algorithm, and ensuring consistency in mass production.

[0029] Traditional temperature control parameters (k, b) may gradually decrease in temperature control accuracy over long-term use due to material thermal hysteresis or device aging and failure. The value range of k and b is dynamically calibrated at three points: room temperature, high temperature, and low temperature. It is worth mentioning that this application uses three-point calibration (room temperature, high and low temperatures) to dynamically correct the k and b values, compensate for changes in environmental and device performance, and maintain the long-term stability of the temperature control algorithm.

[0030] Traditional temperature control schemes use periodic sampling, which cannot track sudden temperature changes in real time, leading to excessive instantaneous wavelength fluctuations. Therefore, the MCU reads the resistance value of the second thermistor in real time during operation, calculates the temperature value T2, calculates the target value T1 based on a linear relationship, and adjusts the TEC to bring T1 to the target value, thereby accurately controlling the laser wavelength. It is worth mentioning that this scheme achieves millisecond-level feedback control by using the MCU to read the thermistor data in real time and adjust the TEC, suppressing transient temperature fluctuations and ensuring instantaneous wavelength stability.

[0031] It is worth mentioning that by adding a second thermistor, this solution can more precisely control the temperature of the laser, keeping the wavelength stable within the module's operating range (-35℃~85℃), with fluctuations within ±0.01nm, and essentially remaining constant.

[0032] Unless otherwise specified, the equipment components involved in the above embodiments are all conventional equipment components, and the connection methods and control methods involved are all conventional connection methods and control methods unless otherwise specified.

[0033] The present invention has been described in detail above with reference to the embodiments. However, those skilled in the art will understand that, without departing from the spirit of the present invention, various specific parameters in the above embodiments can be changed to form multiple specific embodiments, all of which are common variations of the present invention, and will not be described in detail here.

Claims

1. An optical module capable of controlling the wavelength of a laser to be constant, characterized in that, include: The system includes a laser, a ceramic substrate, a TEC (Transformer Electrode), and at least two first thermistors. The first thermistors and the laser are fixed to the ceramic substrate with silver paste. The ceramic substrate is then fixed to the cold surface of the TEC. The laser is located inside a BOX or TO (Transformer Electrode). The second thermistors are located inside the BOX or TO, outside the TEC. The second thermistors are used to monitor the gas temperature inside the cavity.

2. The optical module with controllable constant laser wavelength according to claim 1, characterized in that, The laser is a DWDM laser with a wavelength range of 1470nm-1625nm.

3. An optical module with controllable constant laser wavelength according to claim 1 or 2, characterized in that, It also includes an MCU, which is used to measure the resistance signal of the thermistor, calculate the target temperature of the TEC according to a preset linear relationship, and adjust the TEC to make the laser temperature reach the target temperature.

4. The optical module with controllable constant laser wavelength according to claim 3, characterized in that, The linear relationship is T1=k T2+b, where T1 is the target temperature of TEC, T2 is the cavity gas temperature monitored by the second thermistor, and k and b are constants obtained through statistical analysis of multiple module tests.

5. The optical module with controllable constant laser wavelength according to claim 4, characterized in that, The range of values ​​for k and b is dynamically corrected through three-point calibration at room temperature, high temperature, and low temperature. The values ​​of k and b are then calculated and written into the MCU.

6. The optical module with controllable constant laser wavelength according to claim 5, characterized in that, When the MCU is working, it reads the resistance value of the second thermistor in real time, calculates the temperature value of T2, calculates the target value of T1 according to the linear relationship, and adjusts the TEC to make T1 reach the target value, thereby accurately controlling the laser wavelength.

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