Miniaturized low-power-consumption and high-gain semiconductor optical amplifier and method thereof

Abstract

The invention provides a miniaturized low-power-consumption and high-gain semiconductor optical amplifier and a method thereof. The optical amplifier comprises a first-stage amplification module and a second-stage amplification module which are arranged in the direction of an optical path, the first-stage amplification module comprises a transmission optical fiber (1), an input isolator (3), a first-stage amplification chip (5) and an intermediate isolator (8) which are sequentially arranged along an optical path; the second-stage amplification module comprises a filter plate (9), a second-stage amplification chip (11), an output isolator (14) and an output optical fiber (16) which are sequentially arranged along an optical path; an optical signal output by the first-stage amplification module through the intermediate isolator is received by a filter of an optical path of the second-stage amplification module; the advantages of semiconductor miniaturization and free space packaging are utilized, two or more chips are integrated into the device, the total gain of the device is improved through segmented gain amplification, meanwhile, the product works at low current, the overall power consumption of the device can be obviously reduced, and the heat dissipation condition of the device is improved.

Description

Technical Field

[0001] The present invention relates to the field of optical fiber communication technology, in particular to a miniaturized, low-power and high-gain semiconductor optical amplifier and a method thereof. Background Art

[0002] Currently, the optical amplifiers used in the field of optical fiber communications are mainly erbium-doped fiber amplifiers (EDFA) and semiconductor amplifiers. With the development of semiconductor materials, from bulk materials, quantum wells to quantum dots, combined with band engineering, semiconductor optical amplifiers have developed rapidly.

[0003] Semiconductor amplifiers are based on the theoretical foundation of semiconductor lasers. After power is applied, the PN junction generates carriers (electron-hole pairs). When external photons pass through the gain medium (PN junction), the carriers transfer energy to the photons, generating a photon with the same amplitude, frequency and phase as the input light. At the same time, the carriers transition from the excited state to the ground state. Since semiconductor amplifiers directly load electrical signals onto the gain medium, they have the advantages of high bandwidth, high speed, low energy consumption and small size compared to EDFA.

[0004] As electrons are injected into the semiconductor active layer, the carrier concentration increases and the gain of the semiconductor also increases. Under a specific current, the semiconductor amplifier has a constant gain G, and the output power increases linearly with the power of the input signal. This gain with a linear relationship between input and output is called small signal gain.

[0005] In semiconductors, excessively high injected carrier concentration or excessively high input light intensity will cause the gain saturation of the semiconductor amplifier, that is, the output power decreases with the increase of injected carrier concentration, or even when the current is not saturated, after the input power reaches a certain value, the output power not only does not increase but decreases.

[0006] Since the interband recombination lifetime of semiconductor amplifiers is only in the nanosecond range, it is more difficult to obtain high population inversion and high linear gain compared with the metastable lifetime of EDFA in the millisecond range. In order to achieve a high gain factor, although the gain factor can be increased by increasing the injection current density, it will be adversely affected by the Auger non-radiative recombination. In the Auger effect, when an electron and a hole recombine, the excess energy is transferred to the second electron instead of emitting light, and then the second electron relaxes back to its original energy level by emitting phonons. Auger recombination is the main reason for the decrease in efficiency at higher currents. This non-radiative recombination process involves the interaction of three carriers, including at least one electron and one hole. The gain is increased by increasing the cavity length, but the back end of the long chip will cause loss due to saturation. At the same time, the high gain of a single chip is prone to self-excited oscillation, which causes resonance due to the residual reflection of the end face, resulting in large ripples and fluctuations in output power.

[0007] In order to increase the gain of a single device, especially when the input light is very small (-45dBm), the output must reach 10dBm, so the gain must reach more than 55dB. At present, the only way is to lengthen the gain medium and increase the current. In the second half of the long gain, due to the high carrier concentration, the gain cannot continue to increase, but will cause gain saturation, that is, the gain decreases. At the same time, as the current increases, the corresponding voltage also increases, and the power consumption will increase exponentially, causing the overall heating of the device to be serious. A large current is required to control the thermoelectric cooler TEC for heat dissipation, which poses a severe challenge to the power consumption and heat dissipation of the device.

[0008] In view of the above situation, the solution of the present invention is proposed. By utilizing the advantages of semiconductor miniaturization and free space packaging, two or more chips are integrated into the device. The overall gain of the device is improved by segmented amplification gain. At the same time, due to the use of low current, the overall power consumption of the device can be significantly reduced, and the heat dissipation conditions of the device can be improved. Summary of the invention

[0009] The present invention proposes a miniaturized, low-power and high-gain semiconductor optical amplifier and a method thereof, which utilizes the advantages of semiconductor miniaturization and free-space packaging to integrate two or more chips into the device, and improves the overall gain of the device by segmented amplification gain. At the same time, this product adopts low current operation, which can significantly reduce the overall power consumption of the device and improve the heat dissipation conditions of the device.

[0010] The present invention adopts the following technical solutions.

[0011] A miniaturized, low-power and high-gain semiconductor optical amplifier, the optical amplifier comprising a first-stage amplification module and a second-stage amplification module arranged along an optical path; the first-stage amplification module comprises a transmission optical fiber (1), an input isolator (3), a first-stage amplification chip (5), and an intermediate isolator (8) arranged in sequence along the optical path; the second-stage amplification module comprises a filter (9), a second-stage amplification chip (11), an output isolator (14), and an output optical fiber (16) arranged in sequence along the optical path; the optical signal output by the first-stage amplification module via the intermediate isolator is received by the filter of the optical path of the second-stage amplification module.

[0012] In the first-stage amplification module, a first hemispherical lens (2) for collimating the signal light spot is provided between the transmission optical fiber and the input isolator, and a second hemispherical lens (4) for collimating the light spot is provided between the input isolator and the first-stage amplification chip; the collimated signal light is transmitted through the input isolator into the first-stage amplification chip for first optical signal amplification, and then output to the intermediate isolator; A third hemispherical lens (7) is provided between the first-stage amplifier chip and the intermediate isolator and is used to collimate the optical signal output by the first-stage amplifier chip.

[0013] In the second-stage amplification module, the filter is used to filter the optical signal input from the first-stage amplification module. The filtered optical signal is transmitted to the second-stage amplification chip for a second optical signal amplification, and then sent to the output optical fiber for output through the output isolator; A fourth hemispherical lens (10) for collimating the optical signal after filtering is provided between the filter plate and the secondary amplifier chip; a fifth hemispherical lens (13) for collimating the optical signal output by the secondary amplifier chip is provided between the secondary amplifier chip and the output isolator; and a sixth hemispherical lens (15) for collimating the output light of the output isolator is provided between the output isolator and the output optical fiber.

[0014] The first-stage amplifier chip has a first chip NTC (6) with a temperature detection function integrated at its COC, and the second-stage amplifier chip has a second chip NTC (12) with a temperature detection function integrated at its COC.

[0015] The optical elements of the first-stage amplification module are all arranged on a first TEC substrate (17) of the thermoelectric cooler; and the optical elements of the second-stage amplification module are all arranged on a second TEC substrate (18) of the thermoelectric cooler.

[0016] The first TEC substrate and the second TEC substrate are both placed inside the metal shell (19) for sealing and packaging.

[0017] The thickness of the metal shell is not less than 1 mm.

[0018] The input isolator (3), the intermediate isolator (8), and the output isolator (14) are all free space isolators that ensure unidirectional transmission of light based on the Faraday rotation effect.

[0019] The input isolator (3), the intermediate isolator (8), and the output isolator (14) are isolators with bipolar isolation function, with an isolation range of 40 dB and a size matching that of the input optical fiber.

[0020] A miniaturized, low-power and high-gain semiconductor optical amplifier is used to achieve a high-gain working method. In the working method, both the primary amplifier chip and the secondary amplifier chip are semiconductor amplifier chips. The semiconductor optical amplifier uses two semiconductor amplifier chips in the internal optical path, and uses a free space isolator and a filter between the two semiconductor amplifier chips to expand the input signal light working range from the linear region to the nonlinear region, so as to fully utilize the gain effect of the two-stage semiconductor amplifier chips to achieve high gain under low power consumption conditions; specifically: The input isolator is placed after the input optical fiber and before the first-stage amplifier chip to effectively prevent the reverse spontaneous radiation light generated by the first-stage amplifier chip during operation from entering the input optical fiber again, thus reducing interference with the input light source. The output light of the first-stage amplifier chip is collimated by the aspheric lens and then enters the intermediate isolator; The intermediate isolator is located between the primary and secondary amplifier chips, and is used to allow the light amplified by the primary amplifier chip to be transmitted unidirectionally into the secondary amplifier chip, preventing the output light of the primary amplifier chip from being reflected back into the primary amplifier chip, causing secondary stimulated amplification of the primary amplifier chip, and avoiding the stimulated amplification effect to reduce the output and cause output optical power oscillation. The intermediate isolator is also used to prevent the reverse spontaneous radiation light of the secondary amplifier chip from entering the primary amplifier chip, causing the output optical power to oscillate and resulting in a decrease and instability of the output optical power; The filter is used to filter the spontaneous radiation light generated by the first-stage amplifier chip, and only retains the signal light to enter the second-stage amplifier. The filter specifications are customized according to different bands as needed. Passive filters or tunable filters MTOF are selected according to the single-wave, multi-wave or tunable harmonic wave application scenarios of optical communications; The optical amplifier uses two NTCs to detect the operating temperature of the two amplifier chips in real time. The thermoelectric cooler TEC substrate controls the substrate temperature through the temperature feedback of the temperature detector to maintain a reliable operating temperature environment for the primary amplifier chip and the secondary amplifier chip. The metal shell hermetically seals the optical components of the optical amplifier to form a vacuum environment to protect the optical components in a constant temperature and constant pressure environment, free from external interference, and ensure that the device works under efficient and stable working conditions.

[0021] The present invention optimizes the technical solution of traditional SOA and utilizes the function of two-stage amplification to solve the problem that the single-stage SOA has difficulty in further improving the gain due to the Auger effect caused by high carrier concentration. Combining the advantages of highly integrated and miniaturized packaging of SOA devices, all optical components and chips are highly integrated onto the substrate of two temperature-controllable thermoelectric coolers by means of free space coupling, thus achieving the advantages of miniaturization, low power consumption and high gain of the amplifier.

[0022] The present invention can achieve high gain of optical amplifiers. This proposal achieves a high gain of 58dB through two-stage amplification. Compared with single-stage amplification, even if the current is added to 1000mA, the maximum gain can only reach 40dB due to the high carrier concentration. The high gain characteristic is very suitable for the very small input conditions (-45dBm) in the field of optical communications, and the output power can reach 13dBm.

[0023] The present invention can achieve low power consumption of the optical amplifier. This proposal realizes a low-current working mode through two-stage amplification, and the power consumption is only 0.46W. In comparison, the power consumption of single-stage amplification is 2.14W, and the power consumption of single-stage amplification is 4.6 times that of the two-stage amplification chip. Therefore, it poses a severe challenge to the heat dissipation of the device, resulting in high total power consumption and poor heat dissipation of the device, which ultimately affects the optical output performance of the device.

[0024] The present invention can realize the miniaturization of the optical amplifier. The input and output optical fibers, the non-spherical, the primary and secondary amplifier chips, the three free space isolators, and the filter are all integrated on the thermoelectric cooling substrate, and the package size is small. Compared with the traditional amplifier, since the traditional amplifier needs external packaging optical devices and the devices are connected with optical fibers, the size is large and it is difficult to further reduce the volume. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments: Attached Figure 1 is a schematic diagram of the present invention; Attached Figure 2 It is a schematic diagram of the amplification working curve of the first-stage amplification chip; Attached Figure 3 It is a schematic diagram comparing the amplification working curves of the primary amplification chip and the secondary amplification chip working together and the amplification working curve of only one amplification chip; In the figure: 1-transmission optical fiber; 2-first hemispherical lens; 3-input isolator; 4-second hemispherical lens; 5-first-stage amplifier chip; 6-first chip NTC; -7-third hemispherical lens; 8-intermediate isolator; 9-filter; 10-fourth hemispherical lens; 11-second-stage amplifier chip; 12-second chip NTC; 13-fifth hemispherical lens; 14-output isolator; 15-sixth hemispherical lens; 16-output optical fiber. DETAILED DESCRIPTION

[0026] like Figure 1 As shown, a miniaturized, low-power and high-gain semiconductor optical amplifier comprises a first-stage amplification module and a second-stage amplification module arranged along the optical path; the first-stage amplification module comprises a transmission optical fiber 1, an input isolator 3, a first-stage amplification chip 5, and an intermediate isolator 8 arranged in sequence along the optical path; the second-stage amplification module comprises a filter 9, a second-stage amplification chip 11, an output isolator 14, and an output optical fiber 16 arranged in sequence along the optical path; the optical signal output by the first-stage amplification module via the intermediate isolator is received by the filter of the optical path of the second-stage amplification module.

[0027] In the first-stage amplification module, a first hemispherical lens 2 for signal light spot collimation is provided between the transmission optical fiber and the input isolator, and a second hemispherical lens 4 for light spot collimation is provided between the input isolator and the first-stage amplification chip; the collimated signal light is transmitted through the input isolator into the first-stage amplification chip for the first optical signal amplification, and then output to the intermediate isolator; A third hemispherical lens 7 for collimating the optical signal output by the first-stage amplifier chip is provided between the first-stage amplifier chip and the intermediate isolator.

[0028] In the second-stage amplification module, the filter is used to filter the optical signal input from the first-stage amplification module. The filtered optical signal is transmitted to the second-stage amplification chip for a second optical signal amplification, and then sent to the output optical fiber for output through the output isolator; A fourth hemispherical lens 10 is provided between the filter and the secondary amplifier chip for collimating the filtered optical signal; a fifth hemispherical lens 13 is provided between the secondary amplifier chip and the output isolator for collimating the output optical signal of the secondary amplifier chip; a sixth hemispherical lens 15 is provided between the output isolator and the output optical fiber for collimating the output light of the output isolator.

[0029] The first-stage amplifier chip integrates a first chip NTC6 with a temperature detection function at its COC, and the second-stage amplifier chip integrates a second chip NTC 12 with a temperature detection function at its COC.

[0030] The optical elements of the first-stage amplification module are all disposed on the first TEC substrate 17 of the thermoelectric cooler; the optical elements of the second-stage amplification module are all disposed on the second TEC substrate 18 of the thermoelectric cooler.

[0031] The first TEC substrate and the second TEC substrate are both placed in the metal housing 19 and sealed.

[0032] The thickness of the metal shell is not less than 1 mm.

[0033] The input isolator 3 , the intermediate isolator 8 , and the output isolator 14 are all free-space isolators that ensure unidirectional transmission of light based on the Faraday rotation effect.

[0034] The input isolator 3, the intermediate isolator 8 and the output isolator 14 are isolators with bipolar isolation function, with an isolation range of 40 dB and a size matching the input optical fiber.

[0035] A miniaturized, low-power and high-gain semiconductor optical amplifier is used to achieve a high-gain working method. In the working method, both the primary amplifier chip and the secondary amplifier chip are semiconductor amplifier chips. The semiconductor optical amplifier uses two semiconductor amplifier chips in the internal optical path, and uses a free space isolator and a filter between the two semiconductor amplifier chips to expand the input signal light working range from the linear region to the nonlinear region, so as to fully utilize the gain effect of the two-stage semiconductor amplifier chips to achieve high gain under low power consumption conditions; specifically: The input isolator is placed after the input optical fiber and before the first-stage amplifier chip to effectively prevent the reverse spontaneous radiation light generated by the first-stage amplifier chip during operation from entering the input optical fiber again, thus reducing interference with the input light source. The output light of the first-stage amplifier chip is collimated by the aspheric lens and then enters the intermediate isolator; The intermediate isolator is located between the primary and secondary amplifier chips, and is used to allow the light amplified by the primary amplifier chip to be transmitted unidirectionally into the secondary amplifier chip, preventing the output light of the primary amplifier chip from being reflected back into the primary amplifier chip, causing secondary stimulated amplification of the primary amplifier chip, and avoiding the stimulated amplification effect to reduce the output and cause output optical power oscillation. The intermediate isolator is also used to prevent the reverse spontaneous radiation light of the secondary amplifier chip from entering the primary amplifier chip, causing the output optical power to oscillate and resulting in a decrease and instability of the output optical power; The filter is used to filter the spontaneous radiation light generated by the first-stage amplifier chip, and only retains the signal light to enter the second-stage amplifier. The filter specifications are customized according to different bands as needed. Passive filters or tunable filters MTOF are selected according to the single-wave, multi-wave or tunable harmonic wave application scenarios of optical communications; The optical amplifier uses two NTCs to detect the operating temperature of the two amplifier chips in real time. The thermoelectric cooler TEC substrate controls the substrate temperature through the temperature feedback of the temperature detector to maintain a reliable operating temperature environment for the primary amplifier chip and the secondary amplifier chip. The metal shell hermetically seals the optical components of the optical amplifier to form a vacuum environment to protect the optical components in a constant temperature and constant pressure environment, free from external interference, and ensure that the device works under efficient and stable working conditions.

[0036] Example: In this example, Figure 1A schematic diagram showing the present embodiment: transmission optical fiber 1, aspheric lenses (2, 4, 7, 10, 13, 15), free space isolators (input isolator 3, intermediate isolator 8 and output isolator 14), first-stage amplifier chip 5, second-stage amplifier chip 11, first-stage chip temperature detection chip NTC 6, second-stage chip temperature detection chip NTC12, filter 9, first-stage thermoelectric cooler TEC 17, second-stage thermoelectric cooler TEC 18, and metal casing 19.

[0037] Input optical fiber 1, spot collimation is performed through non-sphere 2. Non-sphere 2 collimated output light enters free space input isolator 3, isolator output light enters non-sphere 4 for spot collimation, output signal light is transmitted into primary amplifier chip 5 for primary optical signal amplification, amplified optical signal is collimated through non-sphere 7 and enters intermediate isolator 8, isolator output light is filtered through filter 9, filtered light is collimated through non-sphere 10 and enters secondary amplifier chip for amplification, amplified light is collimated through non-sphere 13, non-sphere 13 output light enters output isolator 14, output isolator output light is collimated through non-sphere 15, and finally coupled output to output optical fiber 16. The primary amplifier chip 5 integrates chip NTC 14 with temperature detection function on COC, and the secondary amplifier chip 11 integrates chip NTC12 with temperature detection function on COC. The above optical elements 1-8 are placed on the substrate 17 of the thermoelectric cooler TEC, and the optical elements 9-16 are placed on the substrate 18 of the thermoelectric cooler TEC. The two TEC substrates are placed in a metal shell 19 with a thickness of 1 mm for sealing.

[0038] The input optical fiber 1 is at the input end of the optical fiber amplifier and is used to transmit the input signal light before amplification. The wavelength range of the signal light is not limited to the C band (1530~1565nm) or the L band (1565~1625nm). The wavelength range depends on the optical signal wavelength required for optical communication.

[0039] In this example, the aspheric lens (2, 4, 7, 10, 13, 15) is used to collimate the light spot output by the optical fiber for transmission. It is widely used in free space, collimated coupling of chip and optical fiber. The material is not limited to plastic or optical glass. The focus size ranges from 2 to 11 mm, which is related to the size, shape and wavelength of the light spot transmitted by the optical fiber that needs to be collimated. There is no specific restriction.

[0040] In this example, the free space isolator (3, 8, 14) uses the Faraday rotation effect to ensure unidirectional transmission of light. The isolation of the isolator varies from 20 to 40 dB. It is preferred to use an isolator with a bipolar isolation effect, with an isolation of about 40 dB. The size is selected according to the spot size and is not limited. The input isolator 3 is placed after the input optical fiber and before the first-stage amplifier chip. It can effectively prevent the reverse spontaneous radiation light generated by the first-stage amplifier chip during the working process from entering the input optical fiber again, reducing interference with the input light source. The output light of the input isolator 3 passes through the non-spherical body and enters the first-stage amplifier chip 5 for amplification of the optical signal. The first-stage amplifier core needs to select different gain medium materials according to the gain size, and the different cavity lengths are 1000~3000um, without specific restrictions. This scheme uses a cavity length of 2500um as an example. Assume that the input light is a light of negative 45dBm. The current applied to the first-stage amplifier chip is 200mA, and the corresponding voltage is 1.14V. Therefore, the power consumption of the first-stage chip is 0.23W. Since negative 45dBm is a small signal light injection, the first-stage chip works in the linear region. The corresponding gain at 200mA is 35dB, so the output power is -10dBm. The amplification working curve of the first-stage amplifier chip is as follows: Figure 2 shown.

[0041] From the Gain-Pin curve, we can see that in the linear working area, when the input of the first-stage amplifier chip is between -45 and -28dBm, as the input increases, the gain remains unchanged at 35dB, and when the input exceeds -28dBm, the gain gradually decreases. From the Gain-Output curve, we can see that in the linear working area, the gain corresponding to different outputs remains unchanged at 35dB, and after the output reaches 6dBm, the gain begins to drop sharply with the output until the final gain is around 5dB.

[0042] The output light of the primary chip enters the intermediate isolator 8 through non-spherical collimation. The intermediate isolator is located between the primary and secondary amplifier chips. Its main function is to allow the light amplified by the primary chip to be transmitted from left to right into the secondary amplifier chip, preventing the output light of the primary amplifier chip from reflecting back into the primary amplifier chip, causing the primary amplifier chip to be stimulated to amplify again, which not only reduces the output, but also causes the output optical power to oscillate. At the same time, it also prevents the reverse spontaneous radiation light of the secondary amplifier chip 11 from entering the primary amplifier chip, causing the output optical power to oscillate, and ultimately resulting in a reduction in the output optical power and instability. The filter 9 is used to filter the spontaneous radiation light generated by the amplification of the primary amplifier chip, and only retains the signal light to enter the secondary amplifier. The filter can be customized to different bands according to needs, not limited to C wave or L wave. At the same time, according to different application scenarios of optical communication (single wave, multi-wave or tunable harmonic wave), passive filters (DWDM, CWDM) or tunable filters MTOF are selected. Similarly, only the core working components of the filter are retained, free space combination, no additional packaging is required, and the device is miniaturized.

[0043] The output light of the filter 9 is collimated by the non-spherical 10 and enters the secondary amplifier chip 11 for secondary amplification. The output light of the primary amplifier is -10dBm. At this time, the input light (>-28dBm) has entered the nonlinear working area for the secondary amplifier. In the nonlinear working area, at a working current of 200mA, the gain corresponding to the -10dBm input is 23dB. Although it is reduced compared to the gain of 35dB in the linear working area, the gain of 23dB can already amplify the -10dBm input light to 13dBm, and the total gain reaches 58dB. In addition, the power consumption of the secondary amplifier is also 0.23W, and the total power consumption of the two amplifier chips is 0.46W.

[0044] like Figure 3 As shown in the figure, if a single chip is used, and the current is simply added to 400mA, the voltage is 1.43V, and the power consumption is 0.57W, which is greater than the total power consumption of the two chips. Under the condition of -45dBm injection, the total gain of the two-stage amplifier chip working in the linear region is 38dB, so the output power is -7dBm. If the current of the two-stage amplifier is added to the limit of 1000mA, the voltage is 2.14V, the total power consumption is 2.14W, and the power consumption is 4.6 times that of the two-stage amplifier chip. However, due to the high carrier concentration, the limit gain is 40dB, and the output power is -5dBm, which is much smaller than the gain of the two-stage amplifier chip of 58dB. At the same time, due to the high power consumption of the chip, the power consumption of the thermoelectric cooler TEC used for cooling must also be doubled to control the temperature of the chip, thus posing a severe challenge to the heat dissipation of the device.

[0045] The temperature detection chip NTC 6 is integrated on the primary amplifier chip, and the temperature detection chip NTC 12 is integrated on the secondary amplifier chip. The two NTCs detect the chip working temperature in real time. The thermoelectric cooler TEC substrates 17 and 18 can effectively control the primary and secondary chips to work at ideal temperature conditions in real time through the temperature feedback of the temperature detectors, heating the substrates at low temperatures and cooling the substrates at high temperatures. The metal housing 19 hermetically seals all optical components (vacuum conditions) to protect the optical components at a constant temperature and pressure, free from external interference, and ensure that the device works under efficient and stable working conditions.

[0046] This example can solve the problem that the single-chip semiconductor amplifier is adversely affected by Auger non-radiative recombination under high current, resulting in gain saturation, the output power is not proportional to the injected current, and the gain cannot be further improved; in this example, in order to achieve high gain, two semiconductor amplifier chips are used, and a free space isolator and filter are used between the two semiconductor amplifier chips, which can realize the signal light operation from the linear region to the nonlinear region, fully utilizing the gain effect of the semiconductor, and achieving low power consumption and high gain at the same time.

Claims

1. A miniaturized, low-power and high-gain semiconductor optical amplifier, characterized in that: The optical amplifier comprises a first-stage amplification module and a second-stage amplification module arranged along an optical path; the first-stage amplification module comprises a transmission optical fiber (1), an input isolator (3), a first-stage amplification chip (5), and an intermediate isolator (8) arranged in sequence along the optical path; the second-stage amplification module comprises a filter (9), a second-stage amplification chip (11), an output isolator (14), and an output optical fiber (16) arranged in sequence along the optical path; and the optical signal output by the first-stage amplification module via the intermediate isolator is received by the filter of the optical path of the second-stage amplification module.

2. The miniaturized, low-power and high-gain semiconductor optical amplifier according to claim 1, characterized in that: In the first-stage amplification module, a first hemispherical lens (2) for collimating the signal light spot is provided between the transmission optical fiber and the input isolator, and a second hemispherical lens (4) for collimating the light spot is provided between the input isolator and the first-stage amplification chip; the collimated signal light is transmitted through the input isolator into the first-stage amplification chip for first optical signal amplification, and then output to the intermediate isolator; A third hemispherical lens (7) is provided between the first-stage amplifier chip and the intermediate isolator and is used to collimate the optical signal output by the first-stage amplifier chip.

3. The miniaturized, low-power and high-gain semiconductor optical amplifier according to claim 2, characterized in that: In the second-stage amplification module, the filter is used to filter the optical signal input from the first-stage amplification module. The filtered optical signal is transmitted to the second-stage amplification chip for a second optical signal amplification, and then sent to the output optical fiber for output through the output isolator; A fourth hemispherical lens (10) for collimating the optical signal after filtering is provided between the filter plate and the secondary amplifier chip; a fifth hemispherical lens (13) for collimating the optical signal output by the secondary amplifier chip is provided between the secondary amplifier chip and the output isolator; and a sixth hemispherical lens (15) for collimating the output light of the output isolator is provided between the output isolator and the output optical fiber.

4. The miniaturized, low-power and high-gain semiconductor optical amplifier according to claim 1, characterized in that: The first-stage amplifier chip has a first chip NTC (6) with a temperature detection function integrated at its COC, and the second-stage amplifier chip has a second chip NTC (12) with a temperature detection function integrated at its COC.

5. The miniaturized, low-power and high-gain semiconductor optical amplifier according to claim 4, characterized in that: The optical elements of the first-stage amplification module are all arranged on a first TEC substrate (17) of the thermoelectric cooler; and the optical elements of the second-stage amplification module are all arranged on a second TEC substrate (18) of the thermoelectric cooler.

6. The miniaturized, low-power and high-gain semiconductor optical amplifier according to claim 5, characterized in that: The first TEC substrate and the second TEC substrate are both placed inside the metal shell (19) for sealing and packaging.

7. The miniaturized, low-power and high-gain semiconductor optical amplifier according to claim 5, characterized in that: The thickness of the metal shell is not less than 1 mm.

8. The miniaturized, low-power and high-gain semiconductor optical amplifier according to claim 1, characterized in that: The input isolator (3), the intermediate isolator (8), and the output isolator (14) are all free space isolators that ensure unidirectional transmission of light based on the Faraday rotation effect.

9. The miniaturized, low-power and high-gain semiconductor optical amplifier according to claim 8, characterized in that: The input isolator (3), the intermediate isolator (8), and the output isolator (14) are isolators with bipolar isolation function, with an isolation range of 40 dB and a size matching that of the input optical fiber.

10. A method for realizing high-gain operation of a miniaturized, low-power and high-gain semiconductor optical amplifier, characterized in that: In the working method, both the first-stage amplifier chip and the second-stage amplifier chip are semiconductor amplifier chips. The semiconductor optical amplifier uses two semiconductor amplifier chips in the internal optical path, and uses a free space isolator and a filter between the two semiconductor amplifier chips to expand the input signal light working range from the linear region to the nonlinear region, so as to make full use of the gain effect of the two-stage semiconductor amplifier chips and achieve high gain under low power consumption conditions; specifically: The input isolator is placed after the input optical fiber and before the first-stage amplifier chip to effectively prevent the reverse spontaneous radiation light generated by the first-stage amplifier chip during operation from entering the input optical fiber again, thus reducing interference with the input light source. The output light of the first-stage amplifier chip is collimated by the aspheric lens and then enters the intermediate isolator; The intermediate isolator is located between the primary and secondary amplifier chips, and is used to allow the light amplified by the primary amplifier chip to be transmitted unidirectionally into the secondary amplifier chip, preventing the output light of the primary amplifier chip from being reflected back into the primary amplifier chip, causing secondary stimulated amplification of the primary amplifier chip, and avoiding the stimulated amplification effect to reduce the output and cause output optical power oscillation. The intermediate isolator is also used to prevent the reverse spontaneous radiation light of the secondary amplifier chip from entering the primary amplifier chip, causing the output optical power to oscillate and resulting in a decrease and instability of the output optical power; The filter is used to filter the spontaneous radiation light generated by the first-stage amplifier chip, and only retains the signal light to enter the second-stage amplifier. The filter specifications are customized according to different bands as needed. Passive filters or tunable filters MTOF are selected according to the single-wave, multi-wave or tunable harmonic wave application scenarios of optical communications; The optical amplifier uses two NTCs to detect the operating temperature of the two amplifier chips in real time. The thermoelectric cooler TEC substrate controls the substrate temperature through the temperature feedback of the temperature detector to maintain a reliable operating temperature environment for the primary amplifier chip and the secondary amplifier chip. The metal shell hermetically seals the optical components of the optical amplifier to protect them in a constant temperature and pressure environment, from external interference, and ensure that the components work under efficient and stable working conditions.

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