SOA-pin with narrow wavelength interval and manufacturing method therefor

Abstract

The present invention relates to the technical field of optical communications, in particular to an SOA-PIN with a narrow wavelength interval and a manufacturing method therefor. The manufacturing method comprises: with an SOA chip as a boundary, dividing an optical path into a front optical path and a rear optical path; during coupling of an SOA-PIN, first establishing the front optical path and then establishing the rear optical path; establishing the front optical path on the basis of a reverse bias feature of the SOA chip, the front optical path comprising a first collimating lens, an isolator, a second collimating lens and an optical port which are sequentially arranged; and establishing the rear optical path on the basis of a forward bias feature of the SOA chip, the rear optical path comprising a third collimating lens, a filter, a fourth collimating lens and a PIN chip which are sequentially arranged. The present invention can consider requirements on both the yield and the increasingly dense signal wavelength.

Description

A SOA-PIN with narrow wavelength interval and its manufacturing method

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority from the following patent applications:

[0003] (1) A Chinese patent application entitled “A SOA-PIN with narrow wavelength interval and its manufacturing method”, filed with the China Patent Office on February 21, 2024, with application number CN202410193714.2; Technical Field

[0004] The present invention relates to the technical field of optical communication devices, and in particular to a SOA-PIN with a narrow wavelength interval and a manufacturing method thereof. Background Art

[0005] During the coupling process, traditional SOA-PIN coupling does not utilize the reverse-biased characteristics of the semiconductor optical amplifier (SOA) chip. Instead, it utilizes only the forward-biased characteristics of the SOA, establishing the rear optical path first and then the front optical path. The SOA must operate in forward-biased conditions for amplification, but the SOA itself emits significant broad-spectrum noise light when forward-biased. When only utilizing the forward-biased characteristics of the SOA, the rear optical path must be established first, followed by the front optical path.

[0006] The traditional manufacturing method uses the noise light emitted by the SOA when it is positively biased to couple the noise light into a PIN chip (PD chip), which then decouples the front optical path. During the process of establishing the back optical path, the filter placement angle is strongly correlated with the wavelength of the light passing through. Because the light emitted by the SOA itself is broadband noise, if the placement machine is not precise enough, the filter angle may be misaligned, causing the wavelength of the light passing through the filter to drift and enter the PIN chip. The PIN chip responds to all wavelengths and cannot distinguish whether the wavelength passing through the filter is correct. Therefore, after the back optical path is established, the front optical path is established. When the correct signal wavelength is input from the front optical path, it is found that the signal wavelength has been completely or partially filtered out by the filter with the incorrectly placed angle. This method requires rework, which is a haphazard approach and has a very low yield rate.

[0007] If the signal wavelengths of several SOA-PINs are widely spaced, if the filter only removes some of the signal wavelengths, the signal amplification effect will be affected, but the SOA-PIN can still be used. If the filter removes all the signal wavelengths, the SOA-PIN will be completely unusable.

[0008] In view of this, how to overcome the defects of the existing technology and how to take into account the demand for both yield rate and increasingly dense signal wavelengths is an urgent problem to be solved in this technical field.

[0009] Application Contents

[0010] In order to solve the above technical problems, the present invention provides a SOA-PIN with narrow wavelength interval and a manufacturing method thereof, which takes into account the requirements of both yield rate and increasingly dense signal wavelengths.

[0011] The present invention is achieved in that:

[0012] In a first aspect, the present invention provides a method for manufacturing a narrow wavelength interval SOA-PIN, comprising:

[0013] The optical path is divided into a front optical path and a rear optical path with the SOA chip as the boundary; during SOA-PIN coupling, the front optical path is established first, and then the rear optical path is established;

[0014] The front optical path is established by the reverse polarization characteristics of the SOA chip; the front optical path includes a first collimating lens, an isolator, a second collimating lens and an optical port arranged in sequence;

[0015] The rear optical path is established by the positive polarization characteristic of the SOA chip; the rear optical path includes a third collimating lens, a filter, a fourth collimating lens and a PIN chip which are arranged in sequence.

[0016] In a preferred embodiment, dividing the optical path into a front optical path and a rear optical path with the SOA chip as the boundary specifically includes:

[0017] The SOA chip and the PIN chip are mounted to preset positions and are wire-bonded; the portion from the SOA chip to the optical port is divided into the front optical path; and the portion from the SOA chip to the PIN chip is divided into the rear optical path.

[0018] In a preferred embodiment, establishing the front optical path by using the reverse bias characteristic of the SOA chip specifically includes:

[0019] The isolator and the second collimating lens are installed between the SOA chip and the optical port; wherein the isolator is on a side close to the SOA chip, and the second collimating lens is on a side close to the optical port;

[0020] Adding the first signal light and the second signal light to the optical port; reverse biasing the SOA chip and coupling the optical port, so that the SOA chip has a microampere-level response current output, coupling the first signal light and the second signal light to the maximum, and welding and curing the optical port;

[0021] The first signal light and the second signal light are continuously input, the SOA chip is kept reversely biased, and the first collimating lens is coupled and solidified between the SOA chip and the isolator; and the front optical path is established.

[0022] In a preferred embodiment, establishing the rear optical path by using the forward polarization characteristics of the SOA chip specifically includes:

[0023] The SOA chip is changed to forward bias, so that the first signal light and the second signal light are continuously input and pre-aligned with the filter;

[0024] Pre-coupling the third collimating lens between the SOA chip and the filter, and pre-coupling the fourth collimating lens between the filter and the PIN chip, until the PIN chip has a response current in the microampere level, and adjusting the response currents of the first signal light and the second signal light to maximum;

[0025] Dispensing glue to solidify the filter disc;

[0026] The third collimating lens and the fourth collimating lens are coupled until the response currents of the first signal light and the second signal light to the PIN chip meet the requirements; the third collimating lens and the fourth collimating lens are cured by dispensing glue; and the rear optical path is established.

[0027] In a preferred embodiment, the PIN chip is mounted horizontally or vertically.

[0028] In a second aspect, the present invention provides a narrow wavelength interval SOA-PIN, which is manufactured using the method for manufacturing a narrow wavelength interval SOA-PIN as described in the first aspect, and includes a front optical path and a rear optical path, wherein the front optical path and the rear optical path are divided by the SOA chip.

[0029] In a preferred embodiment, the front optical path includes a first collimating lens, an isolator, a second collimating lens and an optical port arranged in sequence; wherein, the first collimating lens is located on a side close to the SOA chip, and the optical port is located on a side away from the SOA chip; the isolator and the second collimating lens are arranged between the first collimating lens and the optical port, and the isolator is close to the SOA chip, and the second collimating lens is close to the optical port.

[0030] In a preferred embodiment, an adjustment ring is provided on the outer periphery of the optical port housing, and the optical port housing and the second collimating lens housing are fixed by the adjustment ring.

[0031] In a preferred embodiment, the rear optical path includes a third collimating lens, a filter, a fourth collimating lens, and a PIN chip arranged in sequence; wherein the third collimating lens is located on a side close to the SOA chip, and the PIN chip is located on a side away from the SOA chip; the filter and the fourth collimating lens are arranged between the third collimating lens and the PIN chip, with the filter close to the third collimating lens, and the fourth collimating lens close to the PIN chip.

[0032] In a preferred embodiment, the cross-section of the fourth collimating lens is trapezoidal, the first right-angled surface of the fourth collimating lens faces the filter, and the second right-angled surface of the fourth collimating lens faces the PIN chip; the light path from the filter to the fourth collimating lens passes through the first right-angled surface, is reflected on the inclined surface of the fourth collimating lens, passes through the second right-angled surface, and then is emitted to the PIN chip.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. During the SOA-PIN coupling process, signals and noise coexist, making it impossible to distinguish whether the coupled light is noise or signal light. The method of the present invention uses the SOA chip as the boundary, dividing it into a front optical path and a rear optical path. It also utilizes the positive and negative bias characteristics of the SOA and adjusts the traditional coupling sequence from the rear optical path to the front optical path to a coupling sequence from the front optical path to the rear optical path. The advantage is that the front optical path is established first, ignoring the noise influence of the SOA itself, and coupling the real signal light into the PIN chip. This method can effectively suppress the noise light with the signal light to ensure that the light coupled into the PIN is a useful real signal, thereby maximizing the amplification efficiency of the SOA-PIN.

[0035] 2. In the process of establishing the front optical path, because of the presence of the isolator, which can only allow light to pass in the forward direction, the first collimating lens needs to be coupled before assembling the isolator. If the traditional SOA chip forward bias method is also used, coupling can also be achieved, but because the light port is coupled again after assembling the isolator, the optical path after assembling the isolator has actually been refracted, and the light port and the first collimating lens cannot actually achieve the optimal coupling efficiency. The present invention assembles the isolator first when establishing the front optical path, and then couples the first collimating lens and the light port, so that the coupling efficiency of the front optical path can be optimized.

[0036] 3. The SOA-PIN filter placement angle is strongly correlated with the wavelength of the signal that can pass through it. Traditional SOA-PIN manufacturing methods have long relied on the accuracy of the placement machine. When the placement machine accuracy reaches its upper limit, the signal wavelength interval between each SOA-PIN is fixed. The present invention is essentially unaffected by placement machine accuracy. The position and angle of any component in the back-end optical path can be adjusted to ensure that the filter angle precisely captures the upper and lower edge wavelengths of the required signal. This can support SOA-PINs with a signal wavelength interval of 0.1nm. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0038] FIG1 is a flow chart of a method for manufacturing a SOA-PIN with a narrow wavelength interval provided by an embodiment of the present invention;

[0039] FIG2 is an expanded flow chart of step 20 provided in an embodiment of the present invention;

[0040] FIG3 is an expanded flow chart of step 30 provided in an embodiment of the present invention;

[0041] FIG4 is a side cross-sectional view of a SOA-PIN device provided in an embodiment of the present invention;

[0042] FIG5 is a top view of a SOA-PIN device provided in an embodiment of the present invention;

[0043] FIG6 is an optical path diagram of a SOA-PIN device provided by an embodiment of the present invention, flatly attached to a PIN chip;

[0044] FIG7 is an optical path diagram of a SOA-PIN device provided by an embodiment of the present invention, with a PIN chip mounted vertically;

[0045] FIG8 is a flowchart of SOA-PIN coupling according to an embodiment of the present invention;

[0046] FIG9 is a coupling flow chart of a traditional SOA-PIN;

[0047] FIG10 is a diagram showing the coupling principle of the first collimating lens when the conventional SOA-PIN front optical path is established. DETAILED DESCRIPTION

[0048] In the description of the present invention, the terms "inside", "outside", "longitudinal", "lateral", "up", "down", "left", "right", "top", "bottom", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and do not require that the present invention must be constructed and operated in a specific orientation. Therefore, they should not be understood as limiting the present invention.

[0049] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, without departing from the scope of the present invention, a number of variations and improvements may be made by those skilled in the art. These all fall within the scope of protection of the present invention.

[0050] It should be noted that, if there is no conflict, the various features in the embodiments of the present invention can be combined with each other and are all within the scope of protection of this application. Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms and directions used in this specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0051] The embodiment of the present invention is designed in consideration of the problem of increasingly dense yield and signal wavelength requirements. The first core point of the embodiment of the present invention is: utilizing the reverse bias characteristic of the SOA chip, the chip does not emit noise light when reverse biased, and itself presents the characteristics of a photodiode (Photo-Diode, abbreviated as PD), and treating it as a PD to first establish the front optical path. The second core point of the present invention is: the isolator and the second collimating lens can be directly solidified on the front optical path without coupling; and then the optical port and the first collimating lens are coupled to maximize the real signal. The third core point of the present invention is: utilizing the signal light, respectively clamping the upper and lower edges of the required signal, the two signal lights are equal (equal means that the upper and lower wavelengths are not weakened, and the parallel light angle is correct), and when it is maximized, the optical path is established.

[0052] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0053] Example 1

[0054] Embodiment 1 of the present invention provides a method for manufacturing a SOA-PIN with a narrow wavelength interval, as shown in FIG1 , and with reference to FIG4 , FIG5 , and FIG6 , the method for manufacturing a SOA-PIN with a narrow wavelength interval includes the following steps.

[0055] Step 10: Divide the optical path into a front optical path 1 and a rear optical path 2, using the SOA chip 106 as the boundary. During SOA-PIN coupling, establish the front optical path 1 first, followed by the rear optical path 2. This step specifically includes: mounting the SOA chip 106 and the PIN chip 110 at predetermined locations and performing wire bonding; dividing the portion from the SOA chip 106 to the optical port 101 into the front optical path 1; and dividing the portion from the SOA chip 106 to the PIN chip 110 into the rear optical path 2.

[0056] Step 20: Establish the front optical path 1 through the reverse polarization characteristics of the SOA chip 106; the front optical path 1 includes a first collimating lens 105, an isolator 104, a second collimating lens 103 and an optical port 101 arranged in sequence. The second collimating lens has the function of converting the light emitted from the optical fiber in the front optical path into collimated light. The first collimating lens has the function of converting the collimated light in the front optical path into converged light that enters the SOA chip. The isolator has the function of preventing the noise light of the SOA chip itself from hitting the end face of the optical fiber and then reflecting back into the SOA chip. The isolator is a one-way component, that is, it can only pass from the optical fiber to the SOA chip, but cannot allow the noise light of the SOA chip to enter the optical fiber.

[0057] Step 30: Establish the rear optical path 2 using the positive polarization characteristics of the SOA chip 106; the rear optical path 2 includes a third collimating lens 107, a filter 108, a fourth collimating lens 109, and a PIN chip 110, arranged in sequence. The third collimating lens converts the light emitted by the SOA chip in the rear optical path into collimated light. The fourth collimating lens converts the collimated light in the rear optical path into converged light that enters the PIN chip. The filter amplifies the front optical path signal light carrying wavelength information. The filter is then added to the rear optical path to provide a bandpass, allowing only signal light of that wavelength to enter the PIN chip, while suppressing and filtering out noise light of other wavelengths emitted by the SOA chip itself.

[0058] Through the above steps, the SOA chip 106 is used as the boundary to divide the optical path into front optical path 1 and rear optical path 2. The forward and reverse polarization characteristics of the SOA are also utilized, and the coupling sequence is adjusted from rear optical path 2 to front optical path 1, instead of the traditional coupling sequence from rear optical path 2 to front optical path 1. The advantage is that the front optical path 1 is established first, ignoring the noise influence of the SOA itself, and coupling the actual signal light into the PIN chip 109. The SOA-PIN fabricated using this method supports signal wavelength spacing less than 0.1nm.

[0059] As shown in FIG2 , with reference to FIG4 , FIG5 , and FIG6 , in a specific implementation of this preferred embodiment, in step 20 , establishing the front optical path 1 by using the reverse bias characteristic of the SOA chip 106 specifically includes the following steps:

[0060] Step 21: Assemble the isolator 104 and the second collimating lens 103 between the SOA chip 106 and the optical port 101 ; wherein the isolator 104 is located on a side close to the SOA chip 106 , and the second collimating lens 103 is located on a side close to the optical port 101 .

[0061] Step 22: Add the first signal light 201 and the second signal light 202 to the optical port 101; reverse bias the SOA chip 106 and couple it to the optical port 101. At this time, the SOA chip 106 has a microampere-level response current output, and the first signal light 201 and the second signal light 202 are coupled to the maximum. The optical port 101 is then welded and solidified.

[0062] Step 23: Continue inputting the first signal light 201 and the second signal light 202 , maintain reverse biasing of the SOA chip 106 , couple and solidify the first collimating lens 105 between the SOA chip 106 and the isolator 104 ; the front optical path 1 is established.

[0063] In the above process, the reverse bias characteristic of the SOA chip 106 is used to establish the front optical path 1; the front optical path 1 of the SOA-PIN is a double collimating lens structure; the second collimating lens 103 can be directly assembled and cured during assembly without coupling.

[0064] As shown in FIG3 , with reference to FIG4 , FIG5 , and FIG6 , in a specific implementation of this preferred embodiment, in step 30 , establishing the rear optical path 2 by using the forward polarization characteristics of the SOA chip 106 specifically includes the following steps:

[0065] Step 31 : The SOA chip 106 is changed to forward bias, so that the first signal light 201 and the second signal light 202 are continuously input, and pre-aligned with the filter 108 .

[0066] Step 32: Pre-couple the third collimating lens 107 between the SOA chip 106 and the filter 108, and pre-couple the fourth collimating lens 109 between the filter 108 and the PIN chip 110 until the PIN chip 110 has a microampere-level response current, thereby adjusting the response currents of the first signal light 201 and the second signal light 202 to their maximum values. It should be noted that when pre-coupling the third and fourth collimating lenses, if the optical path is as shown in Figure 6 , the third and fourth collimating lenses must be pre-coupled first; if the optical path is as shown in Figure 7 , the third collimating lens only needs to be pre-coupled, and the fourth collimating lens does not need to be pre-coupled. This is because when the third collimating lens is optimally coupled, the response current generated by the PIN chip will reach its maximum value. Adding the fourth collimating lens further increases this response current. When the fourth collimating lens is optimally coupled, the response current of the PIN chip reaches its maximum value.

[0067] Step 33: Apply glue and solidify the filter 108 .

[0068] Step 34: Couple the third collimating lens 107 and the fourth collimating lens 109 until the response currents of the first signal light 201 and the second signal light 202 to the PIN chip 110 meet the requirements; apply glue and cure the third collimating lens 107 and the fourth collimating lens 109; and the rear optical path 2 is established. It should be noted that the first signal light and the second signal light represent the upper and lower limits of the edge wavelength, respectively. When the coupling angle is incorrect, either the upper wavelength or the lower wavelength will be partially attenuated. Only when the photocurrents of the upper and lower wavelengths are balanced is the coupling angle correct. For example, if the parallel light emitted from the third collimating lens rotates too much clockwise, the upper wavelength will be attenuated; if it rotates too much counterclockwise, the lower wavelength will be attenuated. Within a certain range, the angle allows both edge wavelengths to pass simultaneously.

[0069] In the above process, the positive polarization characteristics of the SOA chip 106 are utilized to establish the rear optical path 2. The PIN chip 110 is mounted horizontally or vertically, either horizontally or vertically. When the PIN chip 110 is mounted horizontally, the optical path diagram is shown in FIG6 . In this case, the fourth collimating lens 109 has a trapezoidal cross-section, and the PIN chip 110 is located below the fourth collimating lens 109. When the PIN chip 110 is mounted vertically, the optical path diagram is shown in FIG7 . In this case, the fourth collimating lens 109 has a rectangular cross-section, and the PIN chip 110 is located to the left of the fourth collimating lens 109. It should be noted that the structure shown in FIG6 can save length and space, achieving a more compact design.

[0070] In summary, the embodiments of the present invention have the following advantages: 1. During the coupling process of SOA-PIN, signals and noise coexist, and it is impossible to distinguish whether the coupled noise light or signal light is noise light. The manufacturing method of the present invention is divided into the front optical path and the rear optical path with the SOA chip as the boundary, while utilizing the positive and negative polarization characteristics of the SOA, and adjusting the traditional coupling sequence from the rear optical path to the front optical path to the coupling sequence from the front optical path to the rear optical path. The advantage is that the front optical path is established first, and the noise influence of the SOA itself can be ignored, and the real signal light can be coupled into the PIN chip; this method can make the signal light effectively suppress the noise light to ensure that the light coupled into the PIN is a useful real signal, thereby maximizing the amplification efficiency of the SOA-PIN. 2. In the process of establishing the front optical path, because of the presence of the isolator, and the isolator can only allow light to pass in the forward direction, it is necessary to couple the first collimating lens before assembling the isolator. If the same method of manufacturing a conventional SOA chip with positive bias is adopted, coupling can also be achieved. However, since the optical port is coupled again after assembling the isolator, the optical path after assembling the isolator has actually been refracted, and the optical port and the first collimating lens cannot actually achieve the optimal coupling efficiency. The present invention assembles the isolator first when the front optical path is established, and then couples the first collimating lens and the optical port, which can optimize the coupling efficiency of the front optical path. 3. The mounting angle of the SOA-PIN filter is strongly related to the wavelength of the signal that can pass through it. The manufacturing method of the conventional SOA-PIN has long relied on the precision of the placement machine. When the precision of the placement machine reaches the upper limit, the signal wavelength interval between each SOA-PIN is fixed. The present invention is basically not affected by the precision of the placement machine. The position and angle of any component in the rear optical path can be adjusted so that the angle of the filter accurately catches the upper and lower edge wavelengths of the required signal, and can support SOA-PINs with a signal wavelength interval of 0.1nm.

[0071] Example 2

[0072] Based on the method for fabricating a narrow wavelength interval SOA-PIN provided in Example 1, this preferred embodiment 2 further provides a narrow wavelength interval SOA-PIN fabricated using the method of Example 1. Referring to Figures 4, 5, and 6, the SOA-PIN includes a front optical path 1 and a rear optical path 2, with the front optical path 1 and the rear optical path 2 being separated by an SOA chip 106.

[0073] In a specific implementation of this preferred embodiment, the front optical path 1 includes a first collimating lens 105, an isolator 104, a second collimating lens 103, and an optical port 101, which are arranged in sequence. The first collimating lens 105 is located on a side close to the SOA chip 106, and the optical port 101 is located on a side away from the SOA chip 106. The isolator 104 and the second collimating lens 103 are arranged between the first collimating lens 105 and the optical port 101, with the isolator 104 close to the SOA chip 106 and the second collimating lens 103 close to the optical port 101. In a specific implementation of this preferred embodiment, an adjustment ring 102 is provided on the outer periphery of the housing of the optical port 101, and the housing of the optical port 101 and the housing of the second collimating lens 103 are fixed by the adjustment ring 102.

[0074] In a specific implementation of this preferred embodiment, the rear optical path 2 includes a third collimating lens 107, a filter 108, a fourth collimating lens 109, and a PIN chip 110, which are arranged in sequence; wherein the third collimating lens 107 is located on a side close to the SOA chip 106, and the PIN chip 110 is located on a side away from the SOA chip 106; the filter 108 and the fourth collimating lens 109 are arranged between the third collimating lens 107 and the PIN chip 110, with the filter 108 close to the third collimating lens 107, and the fourth collimating lens 109 close to the PIN chip 110.

[0075] In a specific implementation of this preferred embodiment, as shown in FIG6 , when the PIN chip 110 is placed flat, the cross-section of the fourth collimating lens 109 is trapezoidal, with the first right-angled surface of the fourth collimating lens 109 facing the filter 108 and the second right-angled surface of the fourth collimating lens 109 facing the PIN chip 110. The light path from the filter 108 to the fourth collimating lens 109 passes through the first right-angled surface, is reflected by the inclined surface of the fourth collimating lens 109, and then passes through the second right-angled surface before being emitted to the PIN chip 110. As shown in FIG7 , when the PIN chip 110 is placed vertically, the cross-section of the fourth collimating lens 109 is rectangular, and the PIN chip 110 is located to the left of the fourth collimating lens 109. The light path from the filter 108 to the fourth collimating lens 109 passes through the two parallel surfaces of the fourth collimating lens 109 before being emitted to the PIN chip 110.

[0076] Based on the above structure, this embodiment further describes in detail the SOA-PIN coupling process provided by the embodiment of the present invention and the traditional SOA-PIN coupling process, so as to better illustrate the improvements of the embodiment of the present invention through comparison.

[0077] 8 is a flowchart of SOA-PIN coupling according to an embodiment of the present invention, which includes the following steps:

[0078] In the first step, referring to FIG. 4 and FIG. 5 , the SOA chip 106 and the PIN chip 110 are mounted.

[0079] The second step is gold wire bonding. This process is irrelevant to the present invention and will not be illustrated or described in detail.

[0080] In the third step, referring to FIG. 4 and FIG. 5 , the isolator 104 and the second collimating lens 103 are assembled.

[0081] In the fourth step, referring to Figures 4, 5, 6 and 7, two signal lights are added, namely the first signal light source 201 and the second signal light source 202, to the optical port 101; the SOA chip 106 is reverse biased and coupled to the optical port 101. At this time, the SOA chip 106 has a microampere-level response current output, and the first signal light source 201 and the second signal light source 202 are coupled to the maximum, and the welding is solidified 101.

[0082] Step 5: Continue to input two signal lights, reverse bias the SOA chip 106, and couple and solidify the first collimating lens 105. The front optical path 1 is established.

[0083] In the sixth step, the SOA chip 106 is changed to forward bias, and the first signal light source 201 and the second signal light source 202 are continuously input; and the pre-alignment filter 108 is applied.

[0084] In the seventh step, the third collimating lens 107 and the fourth collimating lens 109 are pre-coupled to the PIN chip 110 so that there is a microampere-level response current, and the response currents of the two signal lights are adjusted to the maximum.

[0085] Step 8: Dispense glue and solidify the filter 108.

[0086] Step 9: Couple the third collimating lens 107 and the fourth collimating lens 109 to ensure that the response currents of the first signal light source 201 and the second signal light source 202 to the PIN chip 110 meet the requirements. Apply glue and cure the third collimating lens 107 and the fourth collimating lens 109. The rear optical path 2 is established.

[0087] FIG9 is a flow chart of a conventional SOA-PIN coupling process, which includes the following steps:

[0088] In the first step, referring to FIG. 4 and FIG. 5 , the SOA chip 106 , the filter 108 , and the PIN chip 110 are mounted.

[0089] The second step is gold wire bonding. This process is irrelevant to the present invention and will not be illustrated or described in detail.

[0090] In the third step, referring to FIG. 4 , FIG. 5 , FIG. 6 and FIG. 7 , the SOA chip 106 is forward-biased. At this time, the SOA chip 106 emits noise light with a wide spectrum, which is used to couple the third collimating lens 107 and the fourth collimating lens 109 and solidify.

[0091] In the fourth step, referring to FIG10 , the SOA chip 106 is forward-biased, and the noise light emitted by the beam quality analyzer 300 and the SOA chip 106 is used to couple and solidify the first collimating lens 105 .

[0092] Step 5: Assemble the isolator 104.

[0093] In the sixth step, the SOA chip 106 is forward-biased, and its characteristic of amplifying optical signals by forward-biasing is used to couple the entire optical path, coupling the missing optical port 101 and the second collimating lens 103 in the welding optical path, so as to maximize the photocurrent of the PIN chip 110.

[0094] Step 7. If the coupled photocurrent in step 6 cannot meet the requirements, rework from step 3.

[0095] In the eighth step, add an adjustable light source and scan the required signal wavelength range to see if it meets the requirements. If part of the signal light is filtered out, start again from the third step.

[0096] As can be seen from the traditional SOA-PIN coupling process, using the traditional coupling method, the rear optical path 000B is first established. Due to the incorrect mounting angle or insufficient precision of the filter 107, some signal light may be filtered out, and the noise light of the SOA chip 106 may be coupled out. In other words, the coupling wavelength is incorrect.

[0097] In the SOA-PIN coupling process provided by the present embodiment, the present invention utilizes the reverse bias characteristics of SOA chip 106, establishes the front optical path 000A first, and uses dual signal light 201 and 202 inputs. This prevents any signal light from being filtered out, accurately keeping the wavelength within the required signal wavelength range. Furthermore, because the front optical path is established first, the angle of filter 107 can be fine-tuned based on the signal light's needs. This allows for high controllable angular accuracy, and the signal wavelengths amplified by filters of different wavelengths assigned to different SOA-PINs can be kept very close together.

[0098] In summary, the embodiments of the present invention have the following advantages: 1. During the coupling process of SOA-PIN, signals and noise coexist, and it is impossible to distinguish whether the coupled noise light or signal light is noise light. The manufacturing method of the present invention is divided into the front optical path and the rear optical path with the SOA chip as the boundary, while utilizing the positive and negative polarization characteristics of the SOA, and adjusting the traditional coupling sequence from the rear optical path to the front optical path to the coupling sequence from the front optical path to the rear optical path. The advantage is that the front optical path is established first, and the noise influence of the SOA itself can be ignored, and the real signal light can be coupled into the PIN chip; this method can make the signal light effectively suppress the noise light to ensure that the light coupled into the PIN is a useful real signal, thereby maximizing the amplification efficiency of the SOA-PIN. 2. In the process of establishing the front optical path, because of the presence of the isolator, and the isolator can only allow light to pass in the forward direction, it is necessary to couple the first collimating lens before assembling the isolator. If the same method of manufacturing a conventional SOA chip with positive bias is adopted, coupling can also be achieved. However, since the optical port is coupled again after assembling the isolator, the optical path after assembling the isolator has actually been refracted, and the optical port and the first collimating lens cannot actually achieve the optimal coupling efficiency. The present invention assembles the isolator first when the front optical path is established, and then couples the first collimating lens and the optical port, which can optimize the coupling efficiency of the front optical path. 3. The mounting angle of the SOA-PIN filter is strongly related to the wavelength of the signal that can pass through it. The manufacturing method of the conventional SOA-PIN has long relied on the precision of the placement machine. When the precision of the placement machine reaches the upper limit, the signal wavelength interval between each SOA-PIN is fixed. The present invention is basically not affected by the precision of the placement machine. The position and angle of any component in the rear optical path can be adjusted so that the angle of the filter accurately catches the upper and lower edge wavelengths of the required signal, and can support SOA-PINs with a signal wavelength interval of 0.1nm.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Under the concept of the present invention, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes in different aspects of the present invention as described above. For the sake of simplicity, they are not provided in detail. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for fabricating a narrow wavelength interval SOA-PIN, characterized in that: include: The optical path is divided into a front optical path (1) and a rear optical path (2) with the SOA chip (106) as a boundary; during SOA-PIN coupling, the front optical path (1) is established first, and then the rear optical path (2) is established; The front optical path (1) is established by the reverse polarization characteristic of the SOA chip (106); the front optical path (1) comprises a first collimating lens (105), an isolator (104), a second collimating lens (103), and an optical port (101) which are arranged in sequence; The rear optical path (2) is established by the positive polarization characteristic of the SOA chip (106); the rear optical path (2) comprises a third collimating lens (107), a filter (108), a fourth collimating lens (109), and a PIN chip (110) which are arranged in sequence.

2. The method for manufacturing a narrow wavelength interval SOA-PIN according to claim 1, characterized in that: The method of dividing the optical path into a front optical path (1) and a rear optical path (2) with the SOA chip (106) as the boundary specifically includes: The SOA chip (106) and the PIN chip (110) are mounted at preset positions and subjected to gold wire bonding; the portion from the SOA chip (106) to the optical port (101) is divided into the front optical path (1); and the portion from the SOA chip (106) to the PIN chip (110) is divided into the rear optical path (2).

3. The method for manufacturing a narrow wavelength interval SOA-PIN according to claim 1, characterized in that: The step of establishing the front optical path (1) by using the reverse bias characteristic of the SOA chip (106) specifically includes: The isolator (104) and the second collimating lens (103) are assembled between the SOA chip (106) and the optical port (101); wherein the isolator (104) is located on a side close to the SOA chip (106), and the second collimating lens (103) is located on a side close to the optical port (101); Adding a first signal light (201) and a second signal light (202) to the optical port (101); reverse-biasing the SOA chip (106) and coupling the optical port (101); at this time, the SOA chip (106) outputs a response current at the microampere level, coupling the first signal light (201) and the second signal light (202) to the maximum, and welding and solidifying the optical port (101); The first signal light (201) and the second signal light (202) are continuously input, the SOA chip (106) is kept reverse biased, and a circuit is formed between the SOA chip (106) and the isolator (104). The first collimating lens (105) is coupled and solidified; the front optical path (1) is established.

4. The method for manufacturing a narrow wavelength interval SOA-PIN according to claim 1, characterized in that: The step of establishing the rear optical path (2) through the forward polarization characteristics of the SOA chip (106) specifically includes: The SOA chip (106) is changed to a forward bias, so that the first signal light (201) and the second signal light (202) are continuously input, and the filter (108) is pre-aligned; Pre-coupling the third collimating lens (107) between the SOA chip (106) and the filter (108), and pre-coupling the fourth collimating lens (109) between the filter (108) and the PIN chip (110), until the PIN chip (110) has a response current of microampere level, and adjusting the response currents of the first signal light (201) and the second signal light (202) to maximum; Dispensing glue to solidify the filter (108); The third collimating lens (107) and the fourth collimating lens (109) are coupled until the response currents of the first signal light (201) and the second signal light (202) to the PIN chip (110) meet the requirements; the third collimating lens (107) and the fourth collimating lens (109) are glued and solidified; and the rear optical path (2) is established.

5. The method for manufacturing a SOA-PIN with a narrow wavelength interval according to any one of claims 1 to 4, characterized in that: The PIN chip (110) is mounted horizontally or vertically.

6. The method for manufacturing a narrow wavelength interval SOA-PIN according to claim 5, characterized in that: When the PIN chip (110) is flat, the cross section of the fourth collimating lens (109) is trapezoidal, and the PIN chip (110) is located below the fourth collimating lens (109).

7. The method for manufacturing a narrow wavelength interval SOA-PIN according to claim 5, characterized in that: When the PIN chip (110) is attached vertically, the cross section of the fourth collimating lens (109) is rectangular, and the PIN chip (110) is located on the left side of the fourth collimating lens (109).

8. A narrow wavelength interval SOA-PIN, manufactured using the method for manufacturing a narrow wavelength interval SOA-PIN according to any one of claims 1 to 7, characterized in that: It comprises a front optical path (1) and a rear optical path (2), wherein the front optical path (1) and the rear optical path (2) are divided by an SOA chip (106).

9. The narrow wavelength interval SOA-PIN according to claim 8, characterized in that: The front optical path (1) comprises a first collimating lens (105), an isolator (104), a second collimating lens (103) and an optical port (101) which are arranged in sequence; wherein the first collimating lens (105) is located on a side close to the SOA chip (106), and the optical port (101) is located on a side away from the SOA chip (106); the isolator (104) and the second collimating lens (103) are arranged between the first collimating lens (105) and the optical port (101), and the isolator (104) is close to the SOA chip (106), and the second collimating lens (103) is close to the optical port (101).

10. The narrow wavelength interval SOA-PIN according to claim 9, characterized in that: An adjustment ring (102) is provided on the outer periphery of the optical port (101) housing, and the optical port (101) housing and the second collimating lens (103) housing are fixed via the adjustment ring (102).

11. The narrow wavelength interval SOA-PIN according to claim 8, characterized in that: The rear optical path (2) comprises a third collimating lens (107), a filter (108), a fourth collimating lens (109), and a PIN chip (110) which are arranged in sequence; wherein the third collimating lens (107) is located on a side close to the SOA chip (106), and the PIN chip (110) is located on a side away from the SOA chip (106); the filter (108) and the fourth collimating lens (109) are arranged between the third collimating lens (107) and the PIN chip (110), and the filter (108) is close to the third collimating lens (107), and the fourth collimating lens (109) is close to the PIN chip (110).

12. The narrow wavelength interval SOA-PIN according to claim 11, characterized in that: The cross section of the fourth collimating lens (109) is trapezoidal, a first right-angled surface of the fourth collimating lens (109) faces the filter (108), and a second right-angled surface of the fourth collimating lens (109) faces the PIN chip (110); a light path from the filter (108) to the fourth collimating lens (109) passes through the first right-angled surface, is reflected on the inclined surface of the fourth collimating lens (109), passes through the second right-angled surface, and then is emitted to the PIN chip (110).

13. The narrow wavelength interval SOA-PIN according to claim 11, characterized in that: The cross section of the fourth collimating lens (109) is rectangular, the PIN chip (110) is located on the left side of the fourth collimating lens (109), and the light path from the filter (108) to the fourth collimating lens (109) passes through two parallel surfaces of the fourth collimating lens (109) and then is emitted to the PIN chip (110).

14. The SOA-PIN with narrow wavelength interval according to any one of claims 8 to 13, characterized in that: The narrow wavelength interval SOA-PIN supports a signal wavelength interval of less than 0.1 nm.

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