Optical detection chip and wavelength screening method for multi-wavelength optical signals thereof

Abstract

The embodiment of the invention provides an optical detection chip and a wavelength screening method for multi-wavelength optical signals thereof, and belongs to the technical field of optical chips. The optical detection chip comprises an optical coupling unit which couples an input multi-wavelength optical signal into a single-mode waveguide; the optical filtering and amplifying unit comprises a first filter and an optical amplifier, and the first filter screens out a first optical signal from the multi-wavelength optical signals, reflects other optical signals and inputs the first optical signal into the optical amplifier; the noise filtering unit is used for filtering emission noise from the optical amplifier in the first optical signal through filtering screening; the light polarization beam splitting unit is used for receiving the first light signal after the noise is filtered by the noise filtering unit and performing polarization beam splitting to output at least two beams of polarized light; and the optical detection unit receives at least two beams of polarized light and outputs an electric signal corresponding to the first optical signal after coupling conversion. According to the optical detection chip, the emission noise of the optical amplifier is filtered while wavelength screening is carried out, so that high-sensitivity time division receiving of three-mode coexistence optical signals is met.

Description

Technical Field

[0001] The invention belongs to the technical field of optical chips, and in particular relates to an optical detection chip and a wavelength screening method for multi-wavelength optical signals thereof. Background Art

[0002] The current access optical network is in the transition stage from 10G-PON (Passive Optical Network) to the next generation of higher-speed PON technology (such as 50G-PON). ITU-T officially launched the 50G-PON standard project in 2018 and is targeting deployment in 2025.

[0003] In order to support the smooth evolution of 50G-PON, Combo-PON (three-mode coexistence combined wave optical network) technology is recognized as the best solution. Today, Combo-PON optical modules that combine GPON and 10G-PON are highly valued for their good compatibility and convenience in actual engineering deployment. Therefore, it can be expected that in the 50G-PON era, GPON, 10G-PON, and 50G-PON three-mode compatible optical modules can realize 10G optical access networks.

[0004] However, the existing three-mode coexistence optical modules face the following problems when used in optical receivers: (1) In terms of improving receiving sensitivity, SOA+PIN is used to replace APD, but SOA has emission noise. The cost of processing the emission noise is high and the structure is also complex, such as a wavelength division multiplexer with an optical prism attached; (2) In terms of wavelength compatibility, the wavelengths of 50G-PON (1284~1288nm) and 10G-PON (1260~1280nm) in the upstream direction need to meet the isolation requirements under the premise of a narrow spacing of 2nm, which puts higher and more difficult to achieve requirements on optical devices; (3) The upstream wavelength of EPON is 1260~1360nm, which conflicts with the downstream wavelength of 50G-PON 1342nm. The optical reflection signal introduced by this will increase crosstalk and reduce the sensitivity of the optical receiver. At the same time, it is hoped that the three-mode coexistence optical module will be miniaturized and low-cost.

[0005] In view of this, a new type of optical detection chip and a wavelength screening method of a multi-wavelength optical signal thereof are needed to be applied to an optical receiver to solve the above problems. Summary of the invention

[0006] In order to solve at least one aspect of the above-mentioned problems and defects in the prior art, the embodiments of the present invention provide a light detection chip and a wavelength screening method for a multi-wavelength optical signal thereof, which performs wavelength screening by a first filter integrated in an optical filter amplification unit, and filters the emission noise of the optical amplifier by a noise filtering unit, so as to meet the high-sensitivity time-division reception under the coexistence of GPON, 10G-PON and 50G-PON three-modes, thereby achieving a high link budget. The technical solution is as follows:

[0007] According to one aspect of the present invention, a light detection chip is provided. The light detection chip comprises:

[0008] An optical coupling unit couples the input multi-wavelength optical signal into the single-mode waveguide of the optical detection chip;

[0009] An optical filtering and amplifying unit, comprising a first filter and an optical amplifier, wherein the first filter selects a first optical signal from the multi-wavelength optical signal and reflects the remaining optical signals before inputting the first optical signal into the optical amplifier;

[0010] A noise filtering unit, filtering the emission noise from the optical amplifier in the first optical signal by filtering;

[0011] The optical polarization beam splitting unit receives the first optical signal after the noise is filtered by the noise filtering unit and performs polarization beam splitting to output at least two polarized lights;

[0012] The optical detection unit receives at least two polarized light beams and outputs an electrical signal corresponding to the first optical signal after coupling conversion.

[0013] In some embodiments, specifically, the first optical signal is an optical signal of a specified wavelength detected and received by the optical detection chip, and the optical signal of the specified wavelength is any one of a GPON optical signal, a 10G-PON optical signal, and a 50G-PON optical signal.

[0014] In some embodiments, specifically, the optical amplifier is an InP-based semiconductor optical amplifier, which provides gain for any one of the GPON optical signal, the 10G-PON optical signal and the 50G-PON optical signal, and the gain range is 10-30 dB.

[0015] In some embodiments, the first filter is integrated with the optical amplifier, and the first filter is a uniform grating, a chirped grating, or a tilted grating; wherein the first filter is arranged in the optical waveguide layer of the optical detection chip, and the optical amplifier is bonded above the first filter; or, a uniform grating, a chirped grating, or a tilted grating is formed by etching inside the optical amplifier as the first filter.

[0016] In some embodiments, the noise filtering unit is arranged in front of the optical polarization beam splitting unit, and the noise filtering unit includes a second filter, one end of the second filter is connected to the optical amplifier and the other end is connected to the optical polarization beam splitting unit, so that the optical polarization beam splitting unit can receive the first optical signal after the noise is filtered by the second filter.

[0017] In some embodiments, further, a second filter is formed in the waveguide layer of the optical detection chip by etching; the second filter has a bandpass filtering structure, which is any one of a grating-assisted filtering structure, a cascaded non-equal-arm Mach-Zehnder interferometer and a multi-channel interference coupler.

[0018] In some embodiments, the noise filtering unit is arranged behind the optical polarization beam splitting unit, one end of the optical polarization beam splitting unit is connected to the optical amplifier and the other end is connected to the noise filtering unit; the noise filtering unit includes at least two second filters, each of the at least two second filters corresponds to noise filtering for each of the at least two polarized lights separated from the optical polarization beam splitting unit and reflects each polarized light after noise filtering back to the optical polarization beam splitting unit along the original path; the optical polarization beam splitting unit receives the at least two polarized lights after noise filtering and outputs them to the optical detection unit.

[0019] In some embodiments, further, each of the at least two second filters is formed in the waveguide layer of the light detection chip by etching; each of the at least two second filters has a reflective filtering structure, which is a uniform grating, a chirped grating or a tilted grating.

[0020] In some embodiments, the optical polarization beam splitting unit includes an optical polarization beam splitter, which is an optical polarization rotating beam splitter; the at least two polarized light beams are two polarized light beams, and the two polarized light beams are polarized light in TE polarization state and polarized light in TM polarization state respectively.

[0021] In some embodiments, the light detection unit includes a photodetector, which is a photodiode, and the photodiode is any one of an InP photodiode, a PIN photodiode, and an avalanche photodiode.

[0022] In some embodiments, the optical detection unit further includes at least two third filters, each of the at least two third filters correspondingly receives each polarized light of the at least two polarized lights from the optical polarization beam splitter and inputs each polarized light after wavelength screening into the photodetector.

[0023] In some embodiments, specifically, at least two third filters are integrated with the photodetector, and each of the at least two third filters is a uniform grating, a chirped grating, or a tilted grating; wherein each third filter is arranged in the optical waveguide layer of the photodetection chip, and the photodetector is bonded above the at least two third filters; or, a uniform grating, a chirped grating, or a tilted grating is formed by etching inside the photodetector as each third filter.

[0024] According to another aspect of the present invention, a wavelength screening method for a multi-wavelength optical signal is provided. The wavelength screening method uses the optical detection chip described in the above aspect. The wavelength screening method comprises:

[0025] Inputting the multi-wavelength optical signal into the single-mode waveguide of the optical detection chip through the optical coupling unit;

[0026] After filtering out the first optical signal through the first filter and reflecting the remaining optical signals, the first optical signal is input into the optical amplifier for gain amplification;

[0027] filtering the emission noise from the optical amplifier in the first optical signal after gain amplification through filtering by the noise filtering unit;

[0028] The first optical signal after noise filtering is received by an optical polarization beam splitting unit and polarization beam splitting is performed;

[0029] The optical detection unit couples and converts the first optical signal after polarization splitting to output an electrical signal corresponding to the first optical signal.

[0030] In some embodiments, the noise filtering unit is configured to be disposed in front of the optical polarization beam splitting unit, and the noise filtering unit filters the emission noise from the optical amplifier in the first optical signal through a second filter having a bandpass filtering structure, and inputs the first optical signal after the noise is filtered into the optical polarization beam splitting unit.

[0031] In some embodiments, the noise filtering unit is configured to be disposed behind the optical polarization beam splitting unit, and the noise filtering unit filters the emission noise from the optical amplifier in the first optical signal after polarization beam splitting through a second filter having a reflective filtering structure, and reflects each beam of polarized light of the first optical signal after noise filtering back to the optical polarization beam splitting unit along the original path.

[0032] The present invention also provides a plurality of embodiments according to the following aspects, which are specifically as follows:

[0033] Aspect 1: An optical amplifier, used for the optical detection chip described in the above aspects, the optical amplifier includes a first filter integrated therein, the first filter is used to filter out a first optical signal from a multi-wavelength optical signal and reflect the remaining optical signals before inputting the first optical signal into the optical amplifier.

[0034] Aspect 2: According to the optical amplifier of Aspect 1, the first optical signal is an optical signal of a specified wavelength detected and received by the optical detection chip, and the optical signal of the specified wavelength is any one of a GPON optical signal, a 10G-PON optical signal and a 50G-PON optical signal.

[0035] Aspect 3: The optical amplifier according to aspect 2 is an InP-based semiconductor optical amplifier, which provides gain for any one of a GPON optical signal, a 10G-PON optical signal and a 50G-PON optical signal, and the gain range is 10 to 30 dB.

[0036] Aspect 4: According to the optical amplifier of aspect 3, a uniform grating, a chirped grating or a tilted grating is formed inside the optical amplifier by etching as the first filter.

[0037] Aspect 5: A photodetector, used for the light detection chip described in the above aspects, the photodetector includes at least two third filters integrated therein, each of the at least two third filters corresponds to receiving each polarized light of at least two polarized lights from the optical polarization beam splitter and inputting each polarized light after wavelength screening into the photodetector.

[0038] Aspect 6: According to the photodetector of aspect 5, a uniform grating, a chirped grating or a tilted grating is formed inside the photodetector by etching as each third filter.

[0039] Aspect 7: A multi-wavelength optical receiver uses the optical detection chip described in the above aspects to receive and detect an optical signal of a specified wavelength from a multi-wavelength optical signal in which GPON, 10G-PON and 50G-PON modes coexist.

[0040] The optical detection chip and the wavelength screening method of multi-wavelength optical signals provided by the embodiments of the present invention have at least one or part of the following advantages:

[0041] (1) The optical detection chip and the wavelength screening method of the multi-wavelength optical signal provided by the embodiment of the present invention perform wavelength screening through the first filter integrated in the optical filtering and amplifying unit, and filter the emission noise of the optical amplifier through the noise filtering unit, which can meet the high-sensitivity time-division reception under the coexistence of GPON, 10G-PON and 50G-PON three-modes, thereby achieving a high link budget;

[0042] (2) The optical detection chip and the wavelength screening method of the multi-wavelength optical signal provided in the embodiment of the present invention perform wavelength screening by a first filter integrated in the optical filtering and amplifying unit, and filter the emission noise of the optical amplifier by a noise filtering unit, thereby achieving selective detection and reception of the optical signal of the 50G-PON uplink under the premise of ensuring high sensitivity, thereby improving the optical isolation of the OLT port when the three-generation and six-mode 50G-PON coexist;

[0043] (3) The optical detection chip and the wavelength screening method of the multi-wavelength optical signal provided in the embodiment of the present invention filter the emission noise of the optical amplifier through the second filter of the noise filtering unit, effectively avoiding the crosstalk in the optical transmission link and improving the sensitivity of the optical detection chip to detect and receive the specified optical signal;

[0044] (4) The optical detection chip and the wavelength screening method of the multi-wavelength optical signal provided in the embodiment of the present invention can use an InP-based semiconductor optical amplifier to provide gain for any one of the GPON optical signal, the 10G-PON optical signal and the 50G-PON optical signal, thereby achieving gain amplification of the above three-wavelength optical signals on the same optical detection chip, thereby improving the compatibility of the optical detection chip;

[0045] (5) The optical detection chip and the wavelength screening method of multi-wavelength optical signals provided by the embodiments of the present invention integrate the first filter and the optical amplifier to replace the complex wavelength division multiplexer, thereby reducing the chip size and facilitating the miniaturization packaging of the Combo-PON optical module;

[0046] (6) The optical detection chip and the wavelength screening method of the multi-wavelength optical signal provided in the embodiments of the present invention provide two noise filtering unit configuration schemes using a bandpass filter structure and a reflective filter structure, which can realize flexible device selection and integrated packaging, and at the same time improve the sensitivity of receiving the specified wavelength optical signal in a targeted manner;

[0047] (7) The optical detection chip and the wavelength screening method of the multi-wavelength optical signal provided in the embodiment of the present invention add a third filter in the optical detection unit to perform wavelength screening on the polarization splitting optical signal again, thereby further improving the sensitivity and optical isolation of detecting and receiving the specified wavelength optical signal;

[0048] (8) The first filter and the third filter used in the optical detection chip and the wavelength screening method of multi-wavelength optical signals provided in the embodiments of the present invention can use a simple grating structure, and can be flexibly formed in the optical waveguide layer of the optical detection chip through an etching process or directly etched in an optical amplifier or optical detector, thereby simplifying the manufacturing process of the optical detection chip and reducing the manufacturing cost and packaging cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] These and / or other aspects and advantages of the present invention will become apparent and readily understood from the following description of the preferred embodiments in conjunction with the accompanying drawings, in which:

[0050] Figure 1 is a schematic structural diagram of a light detection chip according to a first embodiment of the present invention;

[0051] Figure 2 for Figure 1 A top view of the structure of the light detection chip shown;

[0052] Figure 3 for Figure 1 A cross-sectional view of a structure of a light detection chip shown;

[0053] Figure 4 for Figure 1 A cross-sectional view of another structure of the light detection chip shown;

[0054] Figure 5 is a schematic structural diagram of a light detection chip according to a second embodiment of the present invention;

[0055] Figure 6 for Figure 5 A top view of the structure of the light detection chip shown;

[0056] Figure 7 for Figure 5 A cross-sectional view of a structure of a light detection chip shown;

[0057] Figure 8 for Figure 5 A cross-sectional view of another structure of a light detection chip is shown. DETAILED DESCRIPTION

[0058] The technical solution of the present invention is further specifically described below by examples and in conjunction with the accompanying drawings. In the specification, the same or similar reference numerals indicate the same or similar components. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the overall inventive concept of the present invention and should not be construed as a limitation of the present invention.

[0059] In the field of high-speed optical communication and optical access network, 50G-PON will be the next generation of higher-speed PON technology. The optical detector that supports the smooth evolution of 50G-PON and Combo-PON (three-mode coexistence combined wave optical network) technology will become the core component of GPON, 10G-PON, and 50G-PON three-mode compatible 10G optical access in the 50G-PON era.

[0060] In order to combine the optical signals of different wavelengths corresponding to GPON, 10G-PON, and 50G-PON into one optical fiber for transmission, and separate these signals at the receiving end, the existing technology usually sets a wavelength division multiplexer in the optical module. The wavelength division multiplexer is a device used in the optical wavelength division multiplexing technology to distinguish a series of optical signals with different wavelengths that carry information by wavelength. Through wavelength division multiplexing, multiple optical signals of different wavelengths can be transmitted simultaneously in the same optical fiber, increasing the transmission capacity of the optical fiber.

[0061] At present, the conventional wavelength division multiplexer is to bond the filter to one side of the parallelogram optical prism through optical glue. When light is incident, the light entering the optical prism first passes through the optical glue and enters the filter. The filter can allow a part of the wavelength of the light signal to pass through it, while reflecting another part of the light signal. The reflected light signal enters the optical prism again through the optical glue, and is reflected at the other end into the next filter until the required light is emitted from the filter. Although this method theoretically realizes the time-division reception of light signals of different wavelengths, it is not suitable for industrial production due to the high quality requirements of the optical prism and the optical glue. Therefore, the embodiment of the present invention proposes a new type of optical detection chip with a filtering structure and a wavelength screening method for multi-wavelength optical signals thereof, which realizes high-sensitivity time-division reception under the coexistence of GPON, 10G-PON, and 50G-PON three-modes through a mature and simple filtering structure, thereby improving the link budget.

[0062] See also Figure 1 , shows the structure of an optical detection chip 100 of an embodiment of the present invention, which mainly includes five main parts along the optical signal transmission path: an optical coupling unit 10, an optical filter amplification unit 20, a noise filtering unit 30, an optical polarization beam splitting unit 40 and an optical detection unit 50. The configuration of the above five main parts and the functions they implement are as follows:

[0063] The optical coupling unit 10 couples the input multi-wavelength optical signal into the single-mode waveguide of the optical detection chip 100;

[0064] The optical filter amplification unit 20 includes a first filter 21 and an optical amplifier 22. The first filter 21 selects a first optical signal from the multi-wavelength optical signal and reflects the remaining optical signals before inputting the first optical signal into the optical amplifier 22;

[0065] The noise filtering unit 30 filters the emission noise from the optical amplifier 22 in the first optical signal by filtering;

[0066] The optical polarization beam splitting unit 40 receives the first optical signal after the noise is filtered by the noise filtering unit 30 and performs polarization beam splitting to output at least two polarized lights;

[0067] The optical detection unit 50 receives at least two polarized light beams and outputs an electrical signal corresponding to the first optical signal after coupling conversion.

[0068] In one example, see Figure 2 , showing that according to Figure 1 The top view of the structure of the optical detection chip 100 shown in the figure, wherein the optical coupling unit 10 includes an optical coupler 11. The optical coupler 11 is arranged at one end of the optical detection chip 100 for receiving the optical signal. Alternatively, the optical coupler 11 can use an end coupler, an edge coupler, etc. Preferably, an inverted tapered end coupler is used in each embodiment of the present invention. After being coupled by the optical coupler 11, the optical signal enters the single-mode waveguide of the optical detection chip 100. At this time, the optical signal can be an optical signal of a single wavelength, such as an uplink optical signal or a downlink optical signal of any wavelength among the GPON optical signal, the 10G-PON optical signal and the 50G-PON optical signal; it can also be a multi-wavelength mixed optical signal, for example, a multi-wavelength mixed uplink optical signal or a downlink optical signal that is not completely isolated by the front wavelength division multiplexing unit inside the optical module.

[0069] The optical coupler 11 belongs to a conventional functional device of the optical module. The selection and setting of the single-mode waveguide optical coupler 11 can be designed according to the actual optical detection chip. This example is only an illustrative example, and those skilled in the art should not understand it as a limitation of the present invention. It should also be noted that in each example of the present invention, there are conventional optical devices, functional devices, etc. (such as optical amplifier 22, optical polarization beam splitter used in optical polarization beam splitting unit 40, photodetector 51, chip platform, etc.) similar to the optical coupler 11. The selection and setting of such components can be matched and designed according to the actual needs of the optical detection chip by technical means familiar to those skilled in the art. Therefore, the subsequent description of these conventional components only provides some illustrative examples, and those skilled in the art should not understand it as a limitation of the present invention, and will not be repeated later.

[0070] In one example, the first optical signal is an optical signal of a specified wavelength that the optical detection chip 100 needs to detect and receive. In theory, by adjusting and designing the filtering structure in the optical detection chip 100, such as the first filter 21, the filtering structure in the noise filtering unit 30, etc., it is possible to detect the uplink optical signal and the downlink optical signal of any wavelength received among the GPON optical signal, the 10G-PON optical signal and the 50G-PON optical signal. Specifically, in the embodiment of the present invention, since the optical detection chip 100 is expected to be applied to the future 50G-PON optical line terminal (OLT) to receive the 50G-PON uplink optical signal with a wavelength range of 1284 to 1288 nm, the first optical signal detected and received involved in the following embodiments and their specific implementation methods are all 50G-PON uplink optical signals with a wavelength range of 1284 to 1288 nm.

[0071] In one example, see Figure 3 , which shows a cross-sectional view of the structure of a light detection chip 100 according to an embodiment. Figure 1-Figure 3 As shown, the optical detection chip 100 further includes a chip platform 60, which includes a substrate layer 61 and a waveguide layer 62 formed on the upper surface of the substrate layer 61. The optical coupling unit 10, the optical filter amplification unit 20, the noise filtering unit 30, the optical polarization beam splitting unit 40 and the optical detection unit 50 are all arranged inside or on the upper surface of the waveguide layer 62. Alternatively, the semiconductor material for implementing the chip platform 60 is not limited, and preferably, a III IV I nP platform or a SOI silicon optical platform is used.

[0072] In one example, alternatively, the optical amplifier 22 in the optical filter amplification unit 20 is an InP-based semiconductor optical amplifier (SOA). Since the optical signal entering through the optical coupler 11 may contain any one of the GPON optical signal, the 10G-PON optical signal and the 50G-PON optical signal or a combination of these optical signals, the optical detection chip 100 needs to detect and receive the 50G-PON signal as well as the GPON optical signal and the 10G-PON optical signal. Therefore, the optical amplifier 22 needs to provide gain for the optical signals of each wavelength mentioned above. The InP-based semiconductor optical amplifier has an optical amplification effect on the GPON optical signal, the 10G-PON optical signal and the 50G-PON optical signal. Furthermore, the gain range that can be provided by using the InP-based semiconductor optical amplifier is 10 to 30 dB.

[0073] In one example, the first filter 21 and the optical amplifier 22 are integrated together to form an optical filtering and amplification unit 20. After the multi-wavelength optical signal enters the single-mode waveguide of the optical detection chip 100, it first enters the first filter 21 to filter the GPON optical signal and / or the 10G-PON optical signal while allowing the 50G-PON optical signal to pass through the first filter 21, and then the 50G-PON optical signal enters the optical amplifier 22 for gain amplification.

[0074] In one example, alternatively, Figure 3 As shown, the first filter 21 is arranged in the optical waveguide layer 62 of the optical detection chip 100, and the optical amplifier 22 is bonded above the first filter 21. Specifically, the first filter 21 uses a reflective filter structure, and alternatively, a uniform grating, a chirped grating or a tilted grating can be used. Then, a uniform grating, a chirped grating or a tilted grating is made in the waveguide layer 62 by an etching process. Then, the optical amplifier 22 is bonded above the uniform grating, the chirped grating or the tilted grating by a die bonding process.

[0075] In one example, alternatively, see Figure 4 , shows another structure in which the first filter 21 is arranged inside the optical amplifier 22. Specifically, the first filter 21 with a grating structure such as a uniform grating, a chirped grating or a tilted grating is manufactured in the InGaAsP layer or the AlGaInAs layer in the optical amplifier 22 (taking the InP-based semiconductor optical amplifier as an example) through an etching process.

[0076] When the optical detection chip 100 detects and receives only 50G-PON optical signals, the grating structure of the first filter 21 is designed according to the wavelengths of the GPON optical signal, the 10G-PON optical signal and the 50G-PON optical signal and the grating structure is integrated with the optical amplifier 22. After the multi-wavelength optical signal enters the single-mode waveguide of the optical detection chip 100, the first filter 21 reflects the GPON optical signal and the 10G-PON optical signal so that these optical signals cannot enter the optical amplifier 22. At the same time, the first filter 21 transmits the 50G-PON optical signal into the optical amplifier 22 for gain amplification and continues to transmit, thereby realizing the selective reception and amplification of the optical signal.

[0077] Furthermore, after the first optical signal (e.g., 50G-PON optical signal) filtered by the first filter 21 is gain-amplified in the optical amplifier 22, since the optical amplifier 22 itself generates emission noise, it is also necessary to perform noise filtering on the first optical signal after passing through the optical amplifier 22 to reduce noise and improve the optical signal receiving signal-to-noise ratio. The following describes in detail the structure and working process of the noise filtering unit 30 and the optical polarization beam splitting unit 40 through the two settings of the noise filtering unit 30 of the first embodiment and the second embodiment.

[0078] First embodiment

[0079] See also Figure 1-Figure 4 , shows the structure of the optical detection chip 100 of the first embodiment. In the optical detection chip 100 of the first embodiment, the structures of the optical coupling unit 10 and the optical filter amplifier unit 20 use the specific structures described above. After the first optical signal is output from the optical amplifier 22 after gain amplification, it first enters the noise filter unit 30 and then enters the optical polarization beam splitting unit 40. That is, the noise filter unit 30 is arranged in front of the optical polarization beam splitting unit 40.

[0080] In one example, the noise filtering unit 30 includes a second filter 31-1, one end of which is connected to the optical amplifier 22 and the other end is connected to the optical polarization splitting unit 40, so that the optical polarization splitting unit 40 can receive the first optical signal after the noise is filtered by the second filter 31-1.

[0081] In one example, alternatively, the second filter 31-1 has a bandpass filter structure, which can use a grating-assisted filter structure, a cascaded non-equivalent-arm Mach-Zehnder interferometer (MZI) or a multi-channel interference coupler (MMI), etc. The bandpass range of the bandpass filter structure can be set according to the requirements of the optical detection chip 100 for the detection and reception wavelength of the optical signal. The bandpass range can be set to the wavelength range of the optical signal to be received.

[0082] In one example, alternatively, Figure 3 and Figure 4 As shown, the second filter 31 - 1 is formed in the waveguide layer 62 between the optical filter amplification unit 20 and the optical polarization beam splitting unit 40 of the optical detection chip 100 by an etching process.

[0083] The noise filtering unit 30 filters the emission noise from the optical amplifier 22 in the first optical signal through the second filter 31 - 1 having a bandpass filtering structure, and inputs the first optical signal after the noise is filtered into the optical polarization splitting unit 40 .

[0084] Specifically, taking the reception of 50G-PON optical signals as an example, the passband range of the second filter 31-1 needs to be set within the wavelength range of the 50G-PON optical signals, that is, the passband range is 1284 to 1288 nm. In this way, when the 50G-PON optical signal enters the second filter 31-1 after gain amplification by the optical amplifier 22, the second filter 31-1 can filter out noise signals outside the wavelength range of 1284 to 1288 nm.

[0085] In one example, after the first optical signal passes through the noise filtering unit 30 to filter out noise, it can enter the optical polarization beam splitting unit 40 for polarization beam splitting. Alternatively, the optical polarization beam splitting unit 40 can use the optical polarization beam splitter conventionally used in the optical module. Preferably, an optical polarization rotation beam splitter can be used. The optical polarization beam splitting unit 40 can be used to split the first optical signal into at least two polarized lights for input into the optical detection unit 50 for optical coupling and then converted into electrical signal output.

[0086] In one example, the light detection unit 50 includes a photodetector 51. Alternatively, the photodetector 51 may use various conventional photodiodes. Preferably, the photodiode is any one of an InP photodiode, a PIN photodiode, and an avalanche photodiode.

[0087] In one example, alternatively, the material of the photodiode may be a conventional semiconductor material. Preferably, any one of Ge, GeSi and InGaAs may be used.

[0088] In one example, when a photodiode is used as the photodetector 51, the optical polarization beam splitting unit 40 splits the first optical signal after noise filtering into two polarized lights through the optical polarization beam splitter. Specifically, the two polarized lights are polarized light in the TE polarization state and polarized light in the TM polarization state. Afterwards, the polarized light in the TE polarization state and the polarized light in the TM polarization state are respectively input to the two ends of the photodetector 51 (e.g., a photodiode) to detect and receive the first optical signal.

[0089] Second embodiment

[0090] See also Figure 5-Figure 8, shows the structure of the optical detection chip 100' of the second embodiment. In the optical detection chip 100' of the second embodiment, the structures of the optical coupling unit 10 and the optical filtering and amplifying unit 20 are the same as those of the first embodiment. After the first optical signal is output from the optical amplifier 22 after gain amplification, it first enters the optical polarization beam splitting unit 40' for beam splitting and then enters the noise filtering unit 30'. That is, the noise filtering unit 30' is arranged behind the optical polarization beam splitting unit 40'. Afterwards, after completing the noise filtering in the noise filtering unit 30', it returns to the polarization beam splitting unit 40' and is input to the optical detection unit 50' after polarization beam splitting again to realize the reception and detection of the first optical signal.

[0091] In one example, specifically, Figure 5 As shown, the noise filtering unit 30' is arranged behind the optical polarization beam splitting unit 40', that is, one end (herein defined as the input end) of the optical polarization beam splitting unit 40' is connected to the optical amplifier 22 and the other end (herein defined as the first output end) is connected to the optical amplifier 22. Figure 5 The path ① shown is connected to the noise filtering unit 30 ′.

[0092] In one example, in order to more effectively filter the emission noise from the optical amplifier 22, the noise filtering unit 30' adopts a reflective noise filtering structure, so the noise filtering unit 30' includes at least two reflective second filters. Figure 5 As shown, taking the light polarization beam splitting unit 40' as an example to form two polarized lights, two second filters 31-2 and 31-3 are correspondingly provided, and the two second filters 31-2 and 31-3 perform noise filtering on each of the two polarized lights split from the light polarization beam splitting unit 40' and return each polarized light after noise filtering to the original path ( Figure 5 The path ①) shown is reflected back to the light polarization splitting unit 40'.

[0093] In one example, further, the two second filters 31-2, 31-3 use a reflective filter structure. Alternatively, in the second embodiment, a uniform grating, a chirped grating or a tilted grating is used as a reflective filter structure to form the second filters 31-2, 31-3. Preferably, a chirped grating with good reflection effect and simple structure is used as the second filter 31-2, 31-3.

[0094] In one example, alternatively, in combination Figure 6-Figure 8 As shown, two second filters 31 - 2 , 31 - 3 are formed in the waveguide layer 62 behind the optical polarization beam splitting unit 40 ′ of the optical detection chip 100 ′ by an etching process.

[0095] In one example, the optical polarization beam splitting unit 40' further includes a second output terminal. Figure 5 The second output end is the same as the first output end, and both are polarization split light output ends. The light polarization splitting unit 40' receives at least two polarized lights returning from the noise filtering unit 30' after noise filtering, and outputs the at least two polarization split lights after polarization splitting to the light detection unit 50' through the second output end.

[0096] The noise filtering unit 30' filters the emission noise from the optical amplifier 22 in the first optical signal after polarization beam splitting through the second filters 31-2 and 31-3 having a reflective filtering structure, and reflects each polarized light beam of the first optical signal after noise filtering back to the optical polarization beam splitting unit 40'. The optical polarization beam splitting unit 40' polarizes the first optical signal again and inputs polarized light of different polarization states to the optical detection unit 50'.

[0097] Specifically, taking the reception of 50G-PON optical signals as an example, the reflection wavelength range of the second filters 31-2 and 31-3 needs to be set within the wavelength range of the 50G-PON optical signals, that is, the reflection wavelength range is 1284 to 1288 nm. In this way, when the 50G-PON optical signal is gain-amplified by the optical amplifier 22 and then polarized and split by the optical polarization splitting unit 40', it enters the corresponding second filters 31-2 and 31-3 respectively, the second filters 31-2 and 31-3 can selectively reflect the optical signals in the wavelength range of 1284 to 1288 nm, thereby filtering out the noise signals from the optical amplifier 22.

[0098] In one example, the configuration of the optical polarization beam splitter unit 40' and the optical detection unit 50' is the same as that of the first embodiment, and functional devices commonly used in optical modules can be selected, such as an optical polarization beam splitter and a photodiode. The specific configuration of the optical polarization beam splitter and the photodiode can refer to the description in the first embodiment, and will not be repeated here.

[0099] In one example, preferably, a photodiode is used as the photodetector 51 in the light detection unit 50'. At this time, the optical polarization beam splitting unit 40' splits the first optical signal after noise filtering into two polarized lights through the optical polarization beam splitter. Specifically, the two polarized lights are polarized light in the TE polarization state and polarized light in the TM polarization state. Afterwards, the polarized light in the TE polarization state and the polarized light in the TM polarization state are respectively input to the two ends of the photodiode to realize the detection and reception of the first optical signal.

[0100] In one example, alternatively, a third filter corresponding to the number of input polarized light paths may be provided in the optical detection unit 50' to further screen the first optical signal of the specified wavelength and filter out other wavelength optical signals, noise signals, interference signals, etc. The third filter may be selectively provided in the optical detection unit 50 of the first embodiment, and may also be selectively provided in the optical detection unit 50' of the second embodiment.

[0101] In one example, taking the second embodiment as an example, Figure 7 and Figure 8 As shown, a light detection unit 50' using a photodiode as a photodetector 51 is taken as an example. At this time, the photodiode has two polarized light input paths, namely, respectively used to receive polarized light in the TE polarization state and polarized light in the TM polarization state output from the light polarization beam splitting unit 40'. Two third filters 52-1 and 52-2 are correspondingly arranged on the above two polarized light input paths, so that the two third filters 52-1 and 52-2 respectively receive two polarized lights from the light polarization beam splitting unit 40' and input each polarized light after wavelength screening into the photodetector 51.

[0102] In one example, alternatively, similar to the setting of the optical filtering and amplifying unit 20, the two third filters 52-1 and 52-2 can also be integrated with the photodetector 51. At the same time, similar to the setting of the first filter 21, the two third filters 52-1 and 52-2 also need to use a reflective filter structure, that is, reflect other wavelength optical signals other than the wavelength of the first optical signal to filter out these optical signals and select the first optical signal for transmission. Alternatively, a uniform grating, a chirped grating or a tilted grating can be used. The specific setting process can refer to the aforementioned embodiments and will not be repeated here.

[0103] In one example, alternatively, there are two ways to integrate the two third filters 52-1, 52-2 with the photodetector 51. One way is as follows: Figure 7 As shown, two third filters 52-1, 52-2 are etched in the optical waveguide layer 62 of the optical detection chip 100', and then the photodetector 51 is bonded on top of the two third filters 52-1, 52-2 through a patch. Figure 8 As shown, taking the InP photodiode as an example, two third filters 52-1 and 52-2 are manufactured by etching the InGaAsP layer of the InP photodiode.

[0104] According to another aspect of the present invention, a wavelength screening method for a multi-wavelength optical signal is provided, wherein the wavelength screening method uses the optical detection chip 100 or the optical detection chip 100 ′ described in the above aspects and embodiments to implement wavelength screening through a filtering structure.

[0105] Combination Figure 1-Figure 8 In the first and second embodiments, the wavelength screening method specifically includes:

[0106] Input the multi-wavelength optical signal into the single-mode waveguide of the optical detection chip 100 through the optical coupling unit 10;

[0107] After the first optical signal is filtered out by the first filter 21 and the remaining optical signals are reflected, the first optical signal is input into the optical amplifier 22 for gain amplification;

[0108] The noise filtering unit 30 filters the emission noise from the optical amplifier 22 in the first optical signal after gain amplification;

[0109] The first optical signal after noise filtering is received by the optical polarization beam splitting unit 40 and polarization beam splitting is performed;

[0110] The optical detection unit 50 couples and converts the first optical signal after polarization splitting to output an electrical signal corresponding to the first optical signal.

[0111] In one example, corresponding to the optical detection chip 100 of the first embodiment, the specific workflow of the noise filtering unit 30 and the optical polarization beam splitting unit 40 to implement noise filtering and polarization beam splitting output of the first optical signal includes: the noise filtering unit 30 is configured to be arranged in front of the optical polarization beam splitting unit 40. The noise filtering unit 30 filters the emission noise from the optical amplifier 22 in the first optical signal through the second filter 31-1 with a bandpass filtering structure, and inputs the first optical signal after the noise is filtered into the optical polarization beam splitting unit 40. Among them, the specific settings of the noise filtering unit 30 and the optical polarization beam splitting unit 40 can refer to the description in the first embodiment, and will not be repeated here.

[0112] In one example, corresponding to the optical detection chip 100' of the second embodiment, the specific workflow of the noise filtering unit 30' and the optical polarization beam splitting unit 40' to implement noise filtering and polarization beam splitting output of the first optical signal includes: the noise filtering unit 30' is configured to be arranged behind the optical polarization beam splitting unit 40'. The noise filtering unit 30' filters the emission noise from the optical amplifier 22 in the first optical signal after polarization beam splitting through the second filter 31-2, 31-3 with a reflective filtering structure, and reflects each beam of polarized light of the first optical signal after the noise is filtered back to the optical polarization beam splitting unit 40'. Among them, the specific settings of the noise filtering unit 30' and the optical polarization beam splitting unit 40' can refer to the description in the first embodiment, and will not be repeated here.

[0113] The present invention also provides a plurality of embodiments according to the following aspects, which are specifically as follows:

[0114] Aspect 1: An optical amplifier 22, used in the optical detection chip 100 and the optical detection chip 100' described in the above aspects and embodiments, the optical amplifier 22 includes a first filter 21 integrated therein, and the first filter 21 is used to filter out a first optical signal from a multi-wavelength optical signal and reflect the remaining optical signals before inputting the first optical signal into the optical amplifier 22.

[0115] Aspect 2: According to the optical amplifier 22 of aspect 1, the first optical signal is an optical signal of a specified wavelength detected and received by the optical detection chip 100 or the optical detection chip 100 ′, and the optical signal of the specified wavelength is any one of a GPON optical signal, a 10G-PON optical signal and a 50G-PON optical signal.

[0116] Aspect 3: The optical amplifier 22 according to Aspect 2 is an InP-based semiconductor optical amplifier, which provides gain for any one of the GPON optical signal, the 10G-PON optical signal and the 50G-PON optical signal, and the gain range is 10 to 30 dB.

[0117] Aspect 4: In the optical amplifier 22 according to Aspect 3, a uniform grating, a chirped grating or a tilted grating is formed inside the optical amplifier 22 by etching as the first filter 21 .

[0118] Aspect 5: A photodetector 51, used for the light detection chip 100 or light detection chip 100' described in the above aspects and embodiments, the photodetector 51 includes at least two third filters 52-1, 52-2 integrated therein, each of the at least two third filters 52-1, 52-2 correspondingly receives each polarized light of at least two polarized lights from the light polarization beam splitting unit 40' and inputs each polarized light after wavelength screening into the photodetector 51.

[0119] Aspect 6: According to the photodetector 51 of Aspect 5, a uniform grating, a chirped grating or a tilted grating is formed inside the photodetector 51 by etching as each of the third filters 52 - 1 and 52 - 2 .

[0120] Aspect 7: A multi-wavelength optical receiver (not shown in the figure), using the optical detection chip 100 or optical detection chip 100' described in the above aspects and embodiments, is used to receive and detect optical signals of specified wavelengths from multi-wavelength optical signals in which GPON, 10G-PON and 50G-PON three modes coexist.

[0121] The optical detection chip and the wavelength screening method of multi-wavelength optical signals provided by the embodiments of the present invention have at least one or part of the following advantages:

[0122] (1) The optical detection chip and the wavelength screening method of the multi-wavelength optical signal provided by the embodiment of the present invention perform wavelength screening through the first filter integrated in the optical filtering and amplifying unit, and filter the emission noise of the optical amplifier through the noise filtering unit, which can meet the high-sensitivity time-division reception under the coexistence of GPON, 10G-PON and 50G-PON three-modes, thereby achieving a high link budget;

[0123] (2) The optical detection chip and the wavelength screening method of the multi-wavelength optical signal provided in the embodiment of the present invention perform wavelength screening by a first filter integrated in the optical filtering and amplifying unit, and filter the emission noise of the optical amplifier by a noise filtering unit, thereby achieving selective detection and reception of the optical signal of the 50G-PON uplink under the premise of ensuring high sensitivity, thereby improving the optical isolation of the OLT port when the three-generation and six-mode 50G-PON coexist;

[0124] (3) The optical detection chip and the wavelength screening method of the multi-wavelength optical signal provided in the embodiment of the present invention filter the emission noise of the optical amplifier through the second filter of the noise filtering unit, effectively avoiding the crosstalk in the optical transmission link and improving the sensitivity of the optical detection chip to detect and receive the specified optical signal;

[0125] (4) The optical detection chip and the wavelength screening method of the multi-wavelength optical signal provided in the embodiment of the present invention can use an InP-based semiconductor optical amplifier to provide gain for any one of the GPON optical signal, the 10G-PON optical signal and the 50G-PON optical signal, thereby achieving gain amplification of the above three-wavelength optical signals on the same optical detection chip, thereby improving the compatibility of the optical detection chip;

[0126] (5) The optical detection chip and the wavelength screening method of multi-wavelength optical signals provided by the embodiments of the present invention integrate the first filter and the optical amplifier to replace the complex wavelength division multiplexer, thereby reducing the chip size and facilitating the miniaturization packaging of the Combo-PON optical module;

[0127] (6) The optical detection chip and the wavelength screening method of the multi-wavelength optical signal provided in the embodiments of the present invention provide two noise filtering unit configuration schemes using a bandpass filter structure and a reflective filter structure, which can realize flexible device selection and integrated packaging, and at the same time improve the sensitivity of receiving the specified wavelength optical signal in a targeted manner;

[0128] (7) The optical detection chip and the wavelength screening method of the multi-wavelength optical signal provided in the embodiment of the present invention add a third filter in the optical detection unit to perform wavelength screening on the polarization splitting optical signal again, thereby further improving the sensitivity and optical isolation of detecting and receiving the specified wavelength optical signal;

[0129] (8) The first filter and the third filter used in the optical detection chip and the wavelength screening method of multi-wavelength optical signals provided in the embodiments of the present invention can use a simple grating structure, and can be flexibly formed in the optical waveguide layer of the optical detection chip through an etching process or directly etched in an optical amplifier or optical detector, thereby simplifying the manufacturing process of the optical detection chip and reducing the manufacturing cost and packaging cost.

[0130] Although some embodiments of the present general inventive concept have been shown and described, it will be appreciated by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the present general inventive concept, the scope of which is defined by the claims and their equivalents.

Claims

1. A light detection chip, characterized in that: The light detection chip comprises: An optical coupling unit, which couples the input multi-wavelength optical signal into the single-mode waveguide of the optical detection chip; An optical filtering and amplifying unit, the optical filtering and amplifying unit comprising a first filter and an optical amplifier, the first filter filtering out a first optical signal from a multi-wavelength optical signal and reflecting the remaining optical signals before inputting the first optical signal into the optical amplifier; a noise filtering unit, wherein the noise filtering unit filters out emission noise from the optical amplifier in the first optical signal through filtering; an optical polarization beam splitting unit, which receives the first optical signal after noise is filtered by the noise filtering unit and performs polarization beam splitting to output at least two polarized lights; A light detection unit receives the at least two polarized light beams and outputs an electrical signal corresponding to the first light signal after coupling and conversion.

2. The light detection chip according to claim 1, characterized in that: The first optical signal is an optical signal of a specified wavelength detected and received by the optical detection chip, and the optical signal of the specified wavelength is any one of a GPON optical signal, a 10G-PON optical signal, and a 50G-PON optical signal.

3. The light detection chip according to claim 2, characterized in that: The optical amplifier is an InP-based semiconductor optical amplifier, which provides gain for any one of a GPON optical signal, a 10G-PON optical signal and a 50G-PON optical signal, and the gain range is 10 to 30 dB.

4. The light detection chip according to claim 3, characterized in that: The first filter is integrated with the optical amplifier, and the first filter is a uniform grating, a chirped grating or a tilted grating; wherein, The first filter is arranged in the optical waveguide layer of the optical detection chip, and the optical amplifier is bonded above the first filter; or, A uniform grating, a chirped grating or a tilted grating is formed inside the optical amplifier by etching as the first filter.

5. The light detection chip according to any one of claims 1 to 4, characterized in that: The noise filtering unit is arranged in front of the optical polarization beam splitting unit, and the noise filtering unit includes a second filter, one end of the second filter is connected to the optical amplifier and the other end is connected to the optical polarization beam splitting unit, so that the optical polarization beam splitting unit can receive the first optical signal after the noise is filtered by the second filter.

6. The light detection chip according to claim 5, characterized in that: The second filter is formed in the waveguide layer of the light detection chip by etching; The second filter has a bandpass filter structure, and the bandpass filter structure is any one of a grating-assisted filter structure, a cascaded non-equivalent-arm Mach-Zehnder interferometer, and a multi-channel interference coupler.

7. The light detection chip according to any one of claims 1 to 4, characterized in that: The noise filtering unit is arranged behind the optical polarization beam splitting unit, one end of the optical polarization beam splitting unit is connected to the optical amplifier and the other end is connected to the noise filtering unit; The noise filtering unit comprises at least two second filters, each of the at least two second filters performs noise filtering on each of the at least two polarized lights separated by the light polarization beam splitting unit and reflects each polarized light after noise filtering back to the light polarization beam splitting unit along the original path; The light polarization beam splitting unit receives at least two beams of polarized light after noise filtering and outputs them to the light detection unit.

8. The light detection chip according to claim 7, characterized in that: Each of the at least two second filters is formed in the waveguide layer of the light detection chip by etching; Each of the at least two second filters has a reflective filter structure, and the reflective filter structure is a uniform grating, a chirped grating, or a tilted grating.

9. The light detection chip according to any one of claims 1 to 4, characterized in that: The optical polarization beam splitting unit comprises an optical polarization beam splitter, and the optical polarization beam splitter is an optical polarization rotating beam splitter; The at least two beams of polarized light are two beams of polarized light, and the two beams of polarized light are polarized light in a TE polarization state and polarized light in a TM polarization state respectively.

10. The light detection chip according to claim 9, characterized in that: The light detection unit includes a photodetector, the photodetector is a photodiode, and the photodiode is any one of an InP photodiode, a PIN photodiode, and an avalanche photodiode.

11. The light detection chip according to claim 10, characterized in that: The optical detection unit further comprises at least two third filters, each of the at least two third filters correspondingly receives each polarized light of the at least two polarized lights from the optical polarization beam splitter and inputs each polarized light after wavelength screening into the photodetector.

12. The light detection chip according to claim 11, characterized in that: The at least two third filters are integrated with the photodetector, and each of the at least two third filters is a uniform grating, a chirped grating or a tilted grating; wherein, Each of the third filters is disposed in the optical waveguide layer of the optical detection chip, and the photodetector is bonded above the at least two third filters; or, A uniform grating, a chirped grating or a tilted grating is formed inside the photodetector by etching as each of the third filters.

13. A wavelength screening method for a multi-wavelength optical signal, characterized in that: The wavelength screening method uses the light detection chip according to any one of claims 1 to 12, and the wavelength screening method comprises: Inputting the multi-wavelength optical signal into the single-mode waveguide of the optical detection chip through the optical coupling unit; After filtering out the first optical signal through a first filter and reflecting the remaining optical signals, the first optical signal is input into an optical amplifier for gain amplification; filtering the emission noise from the optical amplifier in the first optical signal after gain amplification through filtering by the noise filtering unit; The first optical signal after noise filtering is received by an optical polarization beam splitting unit and polarization beam splitting is performed; The optical detection unit couples and converts the first optical signal after polarization splitting to output an electrical signal corresponding to the first optical signal.

14. The wavelength screening method according to claim 13, characterized in that: The noise filtering unit is configured to be arranged in front of the optical polarization beam splitting unit. The noise filtering unit filters the emission noise from the optical amplifier in the first optical signal through a second filter with a bandpass filtering structure, and inputs the first optical signal after the noise is filtered into the optical polarization beam splitting unit.

15. The wavelength screening method according to claim 13, characterized in that: The noise filtering unit is configured to be arranged behind the optical polarization beam splitting unit. The noise filtering unit filters the emission noise from the optical amplifier in the first optical signal after polarization beam splitting through a second filter with a reflective filtering structure, and reflects each beam of polarized light of the first optical signal after noise filtering back to the optical polarization beam splitting unit along the original path.

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