A wavelength debugging method for a multi-channel optical module and an optical module

Abstract

The present invention provides a method for wavelength debugging of a multi-channel optical module. The specific process is as follows: Determine the initial temperature of the TEC, with ΔT as the step, record the output optical power and wavelength of each channel at different temperatures, and plot the temperature-optical power curves of each channel; Obtain the TEC temperature T corresponding to the midpoint of the flat region of the optical power of each channel, the wavelength λ corresponding to the temperature T, and the left safety boundary temperature T 左 ' and the right safety boundary temperature T 右 '; Judge whether the wavelength λ of each channel is within the target wavelength range; Calculate the deviation value Δλ between the wavelength λ of each channel and the target wavelength, compare the temperature T and Δλ of each channel, and calculate the final set temperature T' of the TEC; At the same time, compare T' with the left safety boundary temperature T 左 ' or the right safety boundary temperature T 右 ' of each channel to determine whether the wavelength debugging of the product is successful. The invention comprehensively considers the influence of the TEC temperature on the wavelength and optical power, reduces the sensitivity of the optical power to the wavelength change, and improves the stability and reliability of the product.

Description

Technical Field

[0001] The invention belongs to the technical field of optical communications, and in particular relates to a wavelength debugging method for a multi-channel optical module and an optical module. Background Art

[0002] In long-distance optical modules, TEC is usually used to control the temperature of the laser so that the laser always works at a fixed temperature. During debugging, the wavelength of the laser is also adjusted by adjusting the temperature of the TEC so that the wavelength of the laser meets the protocol requirements. Figure 1 The structure of the typical 100G LR4 (10km) optical module's optical transmitter submodule (TOSA) shown in the figure includes a laser, a TEC, a thermistor, a lens for collimating the light emitted by the laser, an optical multiplexing component including four bandpass filters that pass specific wavelengths, a displacement prism, a converging lens, and a fiber adapter. The steps for debugging the wavelength of the optical transmitter submodule are usually as follows: (1) Setting the initial temperature of the TEC (the initial temperature is 50°C); (2) Testing the wavelengths of the four channels; (3) Determining whether the wavelengths of the four channels meet the protocol: (4) Comparing the measured wavelength data of the four channels with the protocol wavelength to obtain the wavelength deviation value, and then calculating the temperature setting target value of the TEC based on the wavelength temperature drift coefficient, and then setting the TEC temperature to the target value so that the wavelengths of the four channels meet the protocol requirements.

[0003] However, the TEC temperature set according to the above method can ensure that the wavelength is within the protocol range, but due to the manufacturing tolerance of the optical multiplexing component, the range of wavelengths that the bandpass filter can pass will be biased, and there will also be angle tolerances in the mounting of the optical multiplexing component. These will change the range of wavelengths that the optical multiplexing component can pass, and it is impossible to ensure that all wavelengths that meet the protocol requirements can pass with relatively low loss. Sometimes, even if it can pass, the wavelength is not within the wavelength range that the bandpass filter can actually pass with low loss, for example: Figure 2 As shown in the figure, the boundary (left boundary) of the protocol wavelength is located in the area where the optical power drops rapidly; or the wavelength is at the boundary of the wavelength range that the bandpass filter can actually pass, for example: Figure 3 As shown in the figure, the boundary of the protocol wavelength (left boundary) is located at the edge of the rapid drop of optical power. In the above two cases, during use, the optical power is very sensitive to the change of wavelength. As long as the wavelength changes slightly, the optical power will drop sharply, thus causing the optical module to fail. Summary of the invention

[0004] The purpose of the present invention is to provide a wavelength debugging method for a multi-channel optical module, which can at least solve some of the defects existing in the prior art.

[0005] To achieve the above object, the present invention adopts the following technical solution:

[0006] A wavelength debugging method for a multi-channel optical module comprises the following steps:

[0007] 1) Determine the initial temperature of TEC, and record the output optical power and wavelength of each channel of the optical module at different temperatures in steps of ΔT, and draw the temperature-optical power curve of each channel of the optical module;

[0008] 2) Obtain the TEC temperature T corresponding to the midpoint of the optical power flat area in the temperature-optical power curve of each channel of the optical module, as well as the left safety boundary temperature T 左 ' and right safety boundary temperature T 右 '; and obtain the wavelength λ corresponding to each channel at temperature T;

[0009] 3) Determine whether the wavelength λ of each channel is within the target wavelength range. If the wavelength λ of each channel is within the target wavelength range, compare the temperature T of each channel and obtain a maximum value T max and a minimum value T min , the final setting temperature of TEC is T'=(T max +T min ) / 2, the wavelength corresponding to each channel at this temperature T' is the wavelength of each channel after debugging; if at least one of the wavelengths λ of each channel is not within the target wavelength range, proceed to step 4);

[0010] 4) Calculate the deviation value Δλ between the wavelength λ of each channel and the target wavelength range. When the wavelength λ is within the target wavelength range, the deviation value Δλ is defined as 0. When the value of the wavelength λ is greater than the upper limit of the target wavelength range, the deviation value Δλ is defined as greater than 0. When the value of the wavelength λ is less than the lower limit of the target wavelength range, the deviation value is defined as less than 0.

[0011] If the deviation values ​​Δλ of each channel are greater than or equal to 0, and at least one is greater than 0, then compare the deviation values ​​Δλ of each channel and obtain a maximum deviation value Δλ max , the final setting temperature of TEC is T'=(T max +T min ) / 2-Δλ max / σ, σ is the temperature drift coefficient of the laser wavelength, and T' is compared with the left safety boundary temperature T of each channel. 左 ', if T' is equal to the T of each channel 左 ' is greater than or equal to 1, the wavelength corresponding to each channel at temperature T' is set as the wavelength after debugging of each channel; otherwise, the optical module product is judged as a defective product and returned for repair;

[0012] If the deviation values ​​Δλ of each channel are less than or equal to 0, and at least one is less than 0, then compare the absolute values ​​of the deviation values ​​Δλ of each channel and obtain a maximum deviation value Δλ min , the final setting temperature of TEC is T'=(T max +T min ) / 2-Δλ min / σ, σ is the temperature drift coefficient of the laser wavelength, and T' is compared with the right safety boundary temperature T of each channel. 右 ', if T' is equal to the T of each channel 右 ' are all less than or equal to 1, the wavelength corresponding to each channel at temperature T' is set as the wavelength after debugging of each channel; otherwise, the optical module product is judged as a defective product and returned for repair;

[0013] If at least one of the deviation values ​​Δλ of each channel is greater than 0 and at least one is less than 0 at the same time, the optical module product is determined to be defective and is returned for repair.

[0014] Furthermore, the initial temperature of the TEC in step 1) is selected so that the temperature-optical power curve of each channel has a complete flat area, and the wavelength of the corresponding channel read covers the range of the agreed wavelength.

[0015] Furthermore, in step 1), ΔT is set to 1°C.

[0016] In addition, the present invention also provides an optical module, which uses the above-mentioned multi-channel optical module wavelength debugging method.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The wavelength debugging method of the multi-channel optical module provided by the present invention can quickly determine the optimal temperature setting of the TEC and the optimal operating wavelength of the laser in the optical module, and the determination of the optimal temperature of the TEC comprehensively considers its influence on the wavelength and the optical power, which can not only ensure that the wavelength is within the agreed wavelength range, but also make the wavelength within the wavelength range that the bandpass filter can actually pass with low loss, reduce the sensitivity of the optical power to the wavelength change, and thus improve the stability and reliability of the product.

[0019] The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the optical transmission submodule structure of a typical 100G LR4 optical module.

[0021] Figure 2 It is a schematic diagram that the boundary of the protocol wavelength in the existing application is located in the area where the optical power drops rapidly;

[0022] Figure 3 This is a schematic diagram showing that the boundary of the protocol wavelength in existing applications is located at the edge where the optical power drops rapidly;

[0023] Figure 4 is a temperature-optical power curve diagram in the present invention;

[0024] Figure 5 4 is a temperature-optical power curve diagram of four channels in an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] This embodiment provides a wavelength debugging method for a multi-channel optical module, which specifically includes the following steps:

[0027] (1) Determine the initial temperature of TEC, and record the output optical power and wavelength of each channel of the optical module at different temperatures in steps of ΔT, and draw the temperature-optical power curve of each channel of the optical module. The initial temperature of TEC is selected so that the temperature-optical power curve of each channel has a complete flat area, and the wavelength of the corresponding channel is read to cover the range of the protocol wavelength; ΔT is usually set to 1°C.

[0028] It should be noted that the definitions of the optical power flat region, the left safety boundary of the optical power flat region, the right safety boundary, and the target wavelength in the present invention are as follows:

[0029] like Figure 4 As shown in the figure, the two points a and b on the left and right when the optical power drops to ΔP from the point with the maximum optical power are used as boundaries. The area between points a and b is defined as the flat area of ​​optical power. Point a is defined as the left boundary of the flat area of ​​optical power, point b is defined as the right boundary of the flat area of ​​optical power, and the midpoint c between points a and b is defined as the midpoint of the flat area of ​​optical power. Point d, the optical power corresponding to point a on the left boundary, after adding Δt to the horizontal coordinate, is defined as the left safety boundary of the flat area of ​​optical power. Point e, the optical power corresponding to point b on the right boundary, after subtracting Δt from the horizontal coordinate, is defined as the right safety boundary of the flat area of ​​optical power. Generally, the value of ΔP is 1 to 2dBm, and the value of Δt is 1 to 3℃.

[0030] The target wavelength is the wavelength range of the protocol wavelength range after being reduced by Δλ. For example, if the protocol wavelength range is 1294.53 to 1296.59 nm, then when Δλ=0.2 nm, the target wavelength range is 1294.73 to 1296.39 nm.

[0031] (2) Obtain the TEC temperature T corresponding to the midpoint of the optical power flat area in the temperature-optical power curve of each channel of the optical module, as well as the left safety boundary temperature T 左 ' and right safety boundary temperature T 右 '; and obtain the wavelength λ corresponding to each channel at temperature T.

[0032] Taking four channels as an example, the TEC temperatures corresponding to the midpoints of the optical power flatness region of the four channels are T1, T2, T3, and T4, and their corresponding wavelengths are λ1, λ2, λ3, and λ4, respectively. The temperatures corresponding to the left safety boundary point d and the right safety boundary point e of the optical power flatness region of the four channels are recorded as T 左1 ' and T 右1 ', T 左2 ' and T 右2 ', T 左3 ' and T 右3 ', T 左4 ' and T 右4 '.

[0033] (3) Determine whether the wavelength λ of each channel is within the target wavelength range. If the wavelength λ of each channel is within the target wavelength range, compare the temperature T of each channel and obtain a maximum value T max and a minimum value T min , the final setting temperature of TEC is T'=(T max +T min ) / 2, the wavelength corresponding to each channel at this temperature T' is the wavelength of each channel after debugging; if at least one of the wavelengths λ of each channel is not within the target wavelength range, go to step (4).

[0034] Specifically, taking 4 channels as an example, determine whether λ1, λ2, λ3, and λ4 are within the target wavelength range. If the values ​​of λ1, λ2, λ3, and λ4 are within the target wavelength range, compare the values ​​of T1, T2, T3, and T4, and the maximum value is recorded as T max , the minimum value is recorded as T min , the final setting temperature of TEC is T'=(T max +T min ) / 2.

[0035] (4) Calculate the deviation Δλ between the wavelength λ of each channel and the target wavelength range. The deviation Δλ is defined as 0 when the wavelength λ is within the target wavelength range; the deviation Δλ is defined as greater than 0 when the wavelength λ is greater than the upper limit of the target wavelength range, and Δλ is the difference between the wavelength λ and the upper limit of the target wavelength range; the deviation is defined as less than 0 when the wavelength λ is less than the lower limit of the target wavelength range, and Δλ is the difference between the wavelength λ and the lower limit of the target wavelength range.

[0036] If the deviation values ​​Δλ of each channel are greater than or equal to 0, and at least one is greater than 0, then compare the deviation values ​​Δλ of each channel and obtain a maximum deviation value Δλ max , the final setting temperature of TEC is T'=(T max +T min ) / 2-Δλ max / σ, σ is the temperature drift coefficient of the laser wavelength, usually about 0.09nm / ℃; at the same time, compare T' with the left safety boundary temperature T of each channel 左 ', if T' is equal to the T of each channel 左 ' are all greater than or equal to 1, then the wavelength corresponding to each channel at temperature T' is set as the wavelength after debugging of each channel; otherwise, the optical module product is judged as defective and returned for repair. Specifically, taking 4 channels as an example, the deviation values ​​Δλ1, Δλ2, Δλ3, and Δλ4 of the 4 channels are all greater than or equal to 0, and at least one is greater than 0, that is, the values ​​of λ1, λ2, Δλ3, and λ4 are all greater than the lower limit of the target wavelength range, and at least one is greater than the upper limit of the target wavelength. At this time, compare the sizes of Δλ1, Δλ2, Δλ3, and Δλ4, and the largest deviation value is recorded as Δλ max , calculate the final set temperature T' of the TEC, and then compare T' with the left safety boundary temperature T of the 4 channels 左1 '、T 左2 '、T 左3 '、T 左4 ', if the ratio of T' to the left safety boundary temperature of the four channels is greater than or equal to 1, the final temperature of TEC is set to T'; if T' is smaller than one or more of the left safety boundary temperatures of the four channels, the wavelength debugging is judged to have failed, and the product is recorded as a defective product for repair.

[0037] If the deviation values ​​Δλ of each channel are less than or equal to 0, and at least one is less than 0, then compare the absolute values ​​of the deviation values ​​Δλ of each channel and obtain a maximum deviation value Δλ min , the final setting temperature of TEC is T'=(T max +T min ) / 2-Δλ min / σ, σ is the temperature drift coefficient of the laser wavelength, and T' is compared with the right safety boundary temperature T of each channel.右 ', if T' is equal to the T of each channel 右 ' are all less than or equal to 1, then the wavelength corresponding to each channel at temperature T' is set as the wavelength after debugging of each channel; otherwise, the optical module product is judged as defective and returned for repair. Specifically, taking 4 channels as an example, the deviation values ​​Δλ1, Δλ2, Δλ3, and Δλ4 of the 4 channels are all less than or equal to 0, and at least one is less than 0, that is, the values ​​of λ1, Δλ2, Δλ3, and Δλ4 are all less than the upper limit of the target wavelength range, and at least one is less than the lower limit of the target wavelength. At this time, compare the sizes of Δλ1, Δλ2, Δλ3, and Δλ4, and the one with the largest absolute value of the deviation is recorded as Δλ min , calculate the final set temperature T' of the TEC, and then compare T' with the right safety boundary temperature T of the four channels 右1 '、T 右2 '、T 右3 '、T 右4 ', if the ratio of T' to the right safety boundary temperature of the four channels is less than or equal to 1, the final temperature of TEC is set to T'; if T' is greater than one or more of the right safety boundary temperatures of the four channels, the wavelength debugging is judged to have failed, and the product is recorded as a defective product for repair.

[0038] If at least one of the deviation values ​​Δλ of each channel is greater than 0 and at least one is less than 0 at the same time, the optical module product is determined to be defective and is returned for repair.

[0039] The wavelength debugging method of a multi-channel optical module of the present invention is specifically described below by taking a four-channel optical module as an example. The specific process is as follows:

[0040] 1. Obtain the protocol wavelength range of the four channels, as shown in Table 1; then determine the target wavelength range of the four channels according to the protocol wavelength of the four channels. The target wavelength is a value Δλ within the protocol wavelength, and Δλ=0.2nm is taken. The target wavelength range of the four channels is shown in Table 2.

[0041] Table 1: Protocol wavelength ranges for the four channels

[0042]

[0043] Table 2: Target wavelength ranges for the four channels

[0044]

[0045] 2. Select the initial temperature of TEC as 35℃, and change the temperature of TEC with ΔT=1℃ as the step, test the output optical power of 4 channels, and obtain the temperature-optical power curves of 4 channels as shown below: Figure 5 As shown, according to Figure 5It is concluded that the left boundary of the optical power flat region corresponds to the TEC temperature T 左 The right boundary of the flat optical power region corresponds to the TEC temperature T 右 , the midpoint of the optical power flat area corresponds to the TEC temperature T, and the left safety boundary of the optical power flat area corresponds to the TEC temperature T 左 ', the right safety boundary of the optical power flat area corresponds to the TEC temperature T 右 ', the minimum value of TEC temperature corresponding to the midpoint of the 4-channel flat area T min 、The maximum value of TEC temperature T corresponding to the midpoint of the flat area of ​​4 channels max , as shown in Table 3.

[0046] Table 3: Indicators corresponding to the temperature-optical power curves of the four channels

[0047]

[0048] 3. The wavelengths corresponding to the temperatures T1, T2, T3, and T4 at the midpoints of the optical power flatness region of the four channels are measured to be 1296.6 nm, 1300.1 nm, 1304.6 nm, and 1309.1 nm, respectively. Based on the target wavelength data in Table 2, the deviation values ​​Δλ of the four channels are calculated, and the results are shown in Table 4.

[0049] Table 4: Deviation values ​​of the 4 channels

[0050]

[0051] It can be seen from the data in Table 4 that Δλ1, Δλ2, Δλ3, and Δλ4 are all greater than or equal to 0, and Δλ1 is greater than 0. At this time, the deviation values ​​Δλ of the four channels are compared, and the largest deviation value Δλ max =0.21nm, then the final setting temperature of TEC is T'=(T max +T min ) / 2-Δλ max / σ=(56+53) / 2-0.21 / 0.09=52.17℃, where σ is the temperature drift coefficient of the laser wavelength, usually about 0.09nm / ℃. At the same time, it can be concluded from Table 3 that T 左1 '=44℃、T 左2 '=45℃、T 左3 '=43℃、T 左4 '=42℃, compare T' with 4 channels T 左1 '、T 左2 '、T 左3 '、T 左4 ', confirm the size of T' and T 左1 '、T 左2 '、T 左3 '、T 左4' are all greater than 1, so the final temperature of TEC is set to T'=52.17℃.

[0052] The above examples are merely illustrative of the present invention and do not constitute a limitation on the protection scope of the present invention. All designs that are the same or similar to the present invention fall within the protection scope of the present invention.

Claims

1. A wavelength debugging method for a multi-channel optical module, characterized in that: The steps include: 1) Determine the initial temperature of TEC, and record the output optical power and wavelength of each channel of the optical module at different temperatures in steps of ΔT, and draw the temperature-optical power curve of each channel of the optical module; 2) Obtain the TEC temperature T corresponding to the midpoint of the optical power flat area in the temperature-optical power curve of each channel of the optical module, as well as the left safety boundary temperature T 左 ' and right safety boundary temperature T 右 '; and obtain the wavelength λ corresponding to each channel at temperature T; where the left safety boundary temperature T 左 ' is the temperature corresponding to the temperature increase of Δt on the left edge of the optical power flat area, and the right safety boundary temperature T 右 ' is the temperature corresponding to the temperature reduction of Δt at the right edge of the optical power flat area, and Δt is 1 to 3°C; 3) Determine whether the wavelength λ of each channel is within the target wavelength range. If the wavelength λ of each channel is within the target wavelength range, compare the temperature T of each channel and obtain a maximum value T max and a minimum value T min , the final setting temperature of TEC is T'=(T max +T min ) / 2, the wavelength corresponding to each channel at this temperature T' is the wavelength of each channel after debugging; if at least one of the wavelengths λ of each channel is not within the target wavelength range, proceed to step 4); 4) Calculate the deviation value Δλ between the wavelength λ of each channel and the target wavelength range. When the wavelength λ is within the target wavelength range, the deviation value Δλ is defined as 0. When the value of the wavelength λ is greater than the upper limit of the target wavelength range, the deviation value Δλ is defined as greater than 0. When the value of the wavelength λ is less than the lower limit of the target wavelength range, the deviation value is defined as less than 0. If the deviation values ​​Δλ of each channel are greater than or equal to 0, and at least one is greater than 0, then compare the deviation values ​​Δλ of each channel and obtain a maximum deviation value Δλ max , the final setting temperature of TEC is T'=(T max +T min ) / 2-Δλ max / σ, σ is the temperature drift coefficient of the laser wavelength, and T' is compared with the left safety boundary temperature T of each channel. 左 ', if T' is equal to the T of each channel 左 ' are all greater than or equal to 1, the wavelength corresponding to each channel at temperature T' is set as the wavelength after debugging of each channel; otherwise, the optical module product is judged as a defective product and is returned for repair; If the deviation values ​​Δλ of each channel are less than or equal to 0, and at least one is less than 0, then compare the absolute values ​​of the deviation values ​​Δλ of each channel and obtain a maximum deviation value Δλ min , the final setting temperature of TEC is T'=(T max +T min ) / 2-Δλ min / σ, σ is the temperature drift coefficient of the laser wavelength, and T' is compared with the right safety boundary temperature T of each channel. 右 ', if T' is equal to the T of each channel 右 ' are all less than or equal to 1, the wavelength corresponding to each channel at temperature T' is set as the wavelength after debugging of each channel; otherwise, the optical module product is judged as a defective product and returned for repair; If at least one of the deviation values ​​Δλ of each channel is greater than 0 and at least one is less than 0 at the same time, the optical module product is determined to be defective and is returned for repair.

2. The wavelength debugging method of a multi-channel optical module according to claim 1, characterized in that: The initial temperature of the TEC in step 1) is selected so that the temperature-optical power curve of each channel has a complete flat area, and the wavelength of the corresponding channel read covers the range of the agreed wavelength.

3. The wavelength debugging method of a multi-channel optical module according to claim 1, characterized in that: In the step 1), ΔT is set to 1°C.

4. An optical module, characterized in that: The optical module uses the multi-channel optical module wavelength debugging method described in any one of claims 1-3.

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