An optical transmitter-router based on multi-wavelength laser and selectable optical beam splitter

Abstract

The present invention discloses an optical transmission router based on a multi-wavelength laser and a selectable optical beam splitter. A multi-wavelength laser is used as a light source, and the emitted optical signal is selected by a selectable optical beam splitter and then output; wherein, the multi-wavelength laser realizes that each wavelength can be loaded with a modulated signal and outputs multiple wavelengths at the same time, and the selectable optical beam splitter splits the light and selects to output from different ports; the multi-wavelength laser constructed based on a multi-channel semiconductor optical amplifier array structure and the selectable beam splitter are combined to realize the selective output of signals of multiple wavelengths from different ports. The present invention can be applied to each node in a distributed routing network and used as an optical transmission router, and has the advantages of compact structure, large single-link bandwidth, fast switching speed, etc.

Description

Technical Field

[0001] The present invention relates to a semiconductor optical transmitter-router, and in particular to an optical transmitter-router based on a multi-wavelength laser and a selectable optical beam splitter. Background Art

[0002] The rapid development of data centers has put forward higher requirements for the speed of information exchange between nodes. The all-optical routing network built based on photonic integrated chip technology does not go through the optical-electrical-optical conversion process, has many advantages such as large capacity, low cost, low energy consumption, and ultra-low latency. It is a very promising solution for realizing data interconnection in future data centers and high-performance computers.

[0003] At present, the common all-optical interconnection chips generally adopt centralized routing networks, which are connected between the central node and each terminal through a photon router based on a wavelength converter or an optical switch array. Each node needs to be connected to other nodes after being exchanged through the central node. Another feasible solution is based on a distributed routing network. In a distributed routing network, each node is connected to other nodes. Each node chooses to connect to other different nodes through changes in wavelength and port. Such a system no longer relies on the photon router at the central node, which increases the fault tolerance of the system and improves the scalability of the system.

[0004] In order to realize the optical transmitter-router function in the distributed routing network, one feasible method is based on tunable laser arrays and wavelength routers. However, the tunable laser array is difficult to manufacture and the process is complicated. In order to align its output wavelength with the corresponding wavelength of the wavelength router, a more complex wavelength control method is required. Since the process of wavelength and port switching is generally based on thermal effects, the switching speed is generally in the microsecond range, which limits its application in scenarios where burst traffic is relatively large and fast link switching is required. Another feasible method is an optical transmitter-router based on an intracavity laser, using a router as an intracavity mode selection device. Its wavelength and port are switched according to the selected semiconductor optical amplifier, and the switching speed is fast, up to nanoseconds.

[0005] However, since this method uses an optical router in the cavity to realize the routing function, the loss in the edge channel is large, which limits its expansion in the number of wavelengths and ports. Summary of the invention

[0006] In view of the shortcomings of the prior art, the object of the present invention is to provide an optical transmitter-router based on a multi-wavelength laser and a selectable optical beam splitter, which can achieve multi-wavelength output with fast switchable output wavelengths and ports.

[0007] The technical solution adopted by the present invention is:

[0008] The present invention is mainly composed of a multi-wavelength laser and a selectable optical beam splitter connected in sequence. The multi-wavelength laser is used to realize the simultaneous output of optical signals of multiple wavelengths. The selectable optical beam splitter is constructed based on a multi-channel semiconductor optical amplifier array structure and is used to control the output of optical signals from different ports.

[0009] The multi-wavelength laser is mainly composed of an N-way input semiconductor optical amplifier array based on a multi-way semiconductor optical amplifier array structure, an N×1 wavelength division multiplexer and an output semiconductor optical amplifier connected in sequence, and each output port of the N-way input semiconductor optical amplifier array is connected to each port of the N×1 wavelength division multiplexer in a one-to-one correspondence;

[0010] An optical resonant cavity is formed by a semiconductor optical amplifier in the N-channel input semiconductor optical amplifier array, an N×1 wavelength division multiplexer and an output semiconductor optical amplifier. In the optical resonant cavity, optical gain is provided by two semiconductor optical amplifiers. The light of the working wavelength of the corresponding input port of the N×1 wavelength division multiplexer has the minimum transmission loss, and the light of the corresponding wavelength can realize laser lasing. The optical signals of N wavelengths are simultaneously output from the N-channel input semiconductor optical amplifier array. At the same time, the N-channel input semiconductor optical amplifier array performs optical switch control on the output N wavelength optical signals. The optical signal of each wavelength is a single wavelength optical signal of the working wavelength under the input port of the N×1 wavelength division multiplexer, and then input into the N×1 wavelength division multiplexer to select the output wavelength for wavelength division multiplexing and beam combination into one channel for processing, and then input into the output semiconductor optical amplifier for loss compensation and then used for output to the selectable optical beam splitter.

[0011] Light of different wavelengths has different losses after being transmitted through any input port of the N×1 wavelength division multiplexer, among which only light of a specific wavelength has the lowest loss, and this wavelength is the working wavelength of this port.

[0012] The N semiconductor optical amplifiers in the N-way input semiconductor optical amplifier array realize multi-wavelength laser output of N working wavelengths and perform optical switch control on the output N-way wavelength optical signals. The output semiconductor optical amplifier compensates for the loss generated by the N×1 wavelength division multiplexer in the resonant cavity to increase the laser output power and outputs it to the selectable optical beam splitter.

[0013] The N-channel input semiconductor optical amplifier array and the output semiconductor optical amplifier are used to provide optical gain and switching functions, and the N×1 wavelength division multiplexer can be used to select the output wavelength.

[0014] The multi-wavelength laser is mainly composed of N-channel single-wavelength laser arrays and N×1 wavelength division multiplexers connected in sequence, each output port of the N-channel single-wavelength laser array is connected to each port of the N×1 wavelength division multiplexer in one-to-one correspondence, and the output wavelength of each single wavelength of the N-channel single-wavelength laser array is the working wavelength of the N×1 wavelength division multiplexer at the output port;

[0015] N optical signals of wavelengths are simultaneously output from N single-wavelength laser arrays, and then input into an N×1 wavelength division multiplexer to be combined into one channel through wavelength division multiplexing for output to a selectable optical beam splitter.

[0016] The single-wavelength laser adopts a conventional single-wavelength laser.

[0017] The selectable optical beam splitter is mainly composed of N-way optical beam splitters and a port selection semiconductor optical amplifier array based on a multi-way semiconductor optical amplifier array structure connected in sequence, and each output port of the N-way optical beam splitter is connected to each port of the N-way input semiconductor optical amplifier array in a one-to-one correspondence;

[0018] The N-way optical beam splitter is designed with a star coupler structure. An optical signal of different wavelengths is input into the N-way optical beam splitter and is split into optical signals of different wavelengths and input into each input port of the N-way input semiconductor optical amplifier array. Each optical signal is switched by the corresponding semiconductor optical amplifier in the port selection semiconductor optical amplifier array, thereby realizing the function of routing multi-wavelength optical signals to different ports.

[0019] The N-channel input semiconductor optical amplifier array / port selection semiconductor optical amplifier array are both multi-channel semiconductor optical amplifier arrays.

[0020] In the present invention, the N-way input semiconductor optical amplifier array and the port selection semiconductor optical amplifier array must adopt the multi-way semiconductor optical amplifier array made of III-V semiconductor materials set by the present invention, and cannot adopt conventional semiconductor optical amplifiers for array arrangement and composition, because: the input semiconductor optical amplifier array is connected to each port of the N×1 wavelength division multiplexer, and the port selection semiconductor optical amplifier array is connected to each output port of the N-way optical beam splitter. The multi-way semiconductor optical amplifier array designed by the present invention corresponds to each port one by one, which can minimize the size of each part and improve the overall integration. Each semiconductor optical amplifier is completed by one-time manufacturing, the manufacturing process is simple, the performance is the same, and uniform multi-wavelength output and routing effect can be achieved.

[0021] The multi-channel semiconductor optical amplifier array is made of III-V semiconductor materials, and other devices except the multi-channel semiconductor optical amplifier array are made of passive materials such as silicon and silicon nitride.

[0022] The N×1 wavelength division multiplexer realizes wavelength division multiplexing by etching a diffraction grating or an arrayed waveguide grating.

[0023] An N-channel modulator array is arranged between the multi-wavelength laser and the selectable optical beam splitter, and the N-channel modulator array is used to modulate each wavelength of the passing optical signal in a direct modulation manner.

[0024] The multi-channel semiconductor optical amplifier array is mainly manufactured in the following manner:

[0025] First, a wafer structure is prepared which is mainly composed of a substrate, a lower cladding layer, an active layer and an upper cladding layer in order from bottom to top, wherein the refractive index of the active layer material is higher than the refractive index of the upper cladding layer and the lower cladding layer material;

[0026] Then, the design pattern is transferred to the surface of the upper cladding layer by photolithography, and the upper cladding layer is removed by wet etching or dry etching to form a ridge waveguide in the upper cladding layer, and a plurality of ridge waveguides are directly prepared according to the design pattern, and then the lower cladding layer and the active layer between adjacent ridge waveguides are etched to form deep etched grooves; thereby, each ridge waveguide of the upper cladding layer is used as a semiconductor optical amplifier, and deep etched grooves are set between adjacent semiconductor optical amplifiers to separate them;

[0027] Next, a silicon oxide insulating layer is deposited on the upper cladding layer and the exposed active layer. A window is then opened in the silicon oxide insulating layer and a P-type electrode connected to the upper cladding layer is made. Finally, an N-type electrode connected to the substrate is made after thinning and polishing the back side of the substrate.

[0028] Voltage / current can be applied between the P-type electrode and the N-type electrode of each semiconductor optical amplifier to convert photons in the active layer and achieve optical gain.

[0029] Each semiconductor optical amplifier in the multi-channel semiconductor optical amplifier array has the same waveguide length and is integrally manufactured in an array manner with the same spacing. An independent P-type electrode is manufactured on each semiconductor optical amplifier, and all semiconductor optical amplifiers use a common N-type electrode.

[0030] A current is applied independently to each semiconductor optical amplifier, thereby providing a light source lasing and switching function for the optical signal passing through the semiconductor optical amplifier:

[0031] For a semiconductor optical amplifier in an N-channel input semiconductor optical amplifier array:

[0032] When the applied current is greater than the threshold current, light amplification occurs, causing the number of particles in the resonant cavity to be reversed, thus achieving laser lasing.

[0033] When the applied current is less than or equal to the threshold current, the light amplification effect is lower than the loss in the optical resonant cavity, the particle number inversion cannot be achieved in the optical resonant cavity, and the optical resonant cavity cannot achieve laser lasing.

[0034] Thus, the semiconductor optical amplifiers in the N-channel input semiconductor optical amplifier array can realize the light source lasing effect by utilizing the semiconductor light amplification function.

[0035] For port selection of semiconductor optical amplifiers in a semiconductor optical amplifier array:

[0036] When the applied current is less than or equal to the threshold current, the optical gain provided by each semiconductor optical amplifier is less than the loss, and the input optical signal is absorbed in the optical resonant cavity, which manifests as an absorption effect;

[0037] When the applied current is greater than the threshold current, the optical gain provided by each semiconductor optical amplifier is greater than the loss, and the input optical signal is conducted in the optical resonant cavity, showing an open effect. Thus, the semiconductor optical amplifiers in the port selection semiconductor optical amplifier array use the semiconductor optical amplification function to achieve a switching effect.

[0038] The lower cladding and upper cladding of the multi-channel semiconductor optical amplifier array are made of binary compound materials, wherein the upper cladding material is P-type doped and the lower cladding material is N-type doped; the active layer is made of multi-quantum well material composed of quaternary compound materials.

[0039] In the first embodiment, the multi-wavelength laser is an intracavity multi-wavelength laser, which is composed of an N-way input semiconductor optical amplifier array, an N×1 wavelength division multiplexer and an output semiconductor optical amplifier. Any input semiconductor optical amplifier in the N-way input semiconductor optical amplifier array, the N×1 wavelength division multiplexer and the output semiconductor optical amplifier form an optical resonant cavity. After applying current to the semiconductor optical amplifier in the optical resonant cavity to provide optical gain, the optical resonant cavity realizes laser lasing, and its lasing wavelength is determined by the N×1 wavelength division multiplexer, that is, the output of a laser of a specific wavelength is realized. If current is applied to all semiconductor optical amplifiers in the N-way input semiconductor optical amplifier array, the simultaneous output of N multi-wavelength lasers is realized; if current is applied to a part of the number of semiconductor optical amplifiers in the N-way input semiconductor optical amplifier array, the laser can realize the simultaneous output of lasers of the corresponding number of wavelengths. Therefore, the multi-wavelength laser in this embodiment can realize the selective output of lasers of different wavelengths.

[0040] In the second embodiment, the multi-wavelength laser is implemented by combining a single-wavelength laser array with a wavelength division multiplexer, which is composed of an N-channel single-wavelength laser array and an N×1 wavelength division multiplexer. Different lasers in the N-channel single-wavelength laser array realize the emission of lasers of different wavelengths, and their output ends are connected to the corresponding input ends of the N×1 wavelength division multiplexer, and the N×1 wavelength division multiplexer combines each wavelength into a beam for output. Selecting different single-wavelength lasers to work can realize the selective output of lasers of different wavelengths.

[0041] In the above two embodiments, the multi-wavelength laser can be directly modulated. In the first embodiment, changing the current applied to the input semiconductor optical amplifier can change the output intensity of the corresponding wavelength optical signal, thereby loading different high-speed modulation signals on different wavelengths. In the second embodiment, changing the current applied to the single-wavelength laser can change the intensity of the laser output signal, thereby loading different high-speed modulation signals on different wavelengths.

[0042] In the above two embodiments, the multi-wavelength laser can also be loaded with high-speed signals by adding an external modulator array. The N-channel modulator array is composed of N modulators, and each modulator can modulate an optical signal of one wavelength. Its implementation method is generally a micro-ring modulator, and the working wavelength of each micro-ring modulator corresponds to an output wavelength of the multi-wavelength laser. By adding an N-channel modulator array between the multi-wavelength laser and the selectable optical beam splitter, different high-speed modulated signals can be loaded at different wavelengths.

[0043] All components of the multi-wavelength laser and the selectable optical beam splitter are integrated on the same chip through monolithic integration or hybrid integration.

[0044] The multi-channel semiconductor optical amplifier array is made of III-V semiconductor materials and is used to convert electrons into photons to provide optical gain, switching and active laser functions. Except for the multi-channel semiconductor optical amplifier array, other devices use passive materials such as silicon and silicon nitride; the two materials are integrated on the same chip through end-face coupling or vertical coupling.

[0045] The solution of the present invention, which is formed by combining a multi-wavelength laser and a selectable optical beam splitter, can realize the multi-wavelength transmitter-router function. The final effect achieved is that each port can output a multi-wavelength laser, and a high-speed modulation signal can be loaded on each wavelength. The final output of the multi-wavelength transmitter-router can be quickly switched between different ports, and its output wavelength can also be quickly switched between different wavelengths. Since the switching principle is based on the current change process of the semiconductor optical amplifier, the switching speed of the port and wavelength is very fast, reaching the nanosecond level.

[0046] The innovation of the present invention lies in realizing the optical emission-router function by integrating multi-wavelength lasers and selectable optical beam splitters, and forming an optical resonant cavity with semiconductor optical amplifiers, which can realize the selective routing output effect of signals of multiple wavelengths from different ports, so that each port can output multi-wavelength signals and achieve a higher transmission bandwidth. In addition, a semiconductor optical amplifier array specially made of III-V semiconductor materials is used as an optical switch to realize the routing output function of multi-wavelength optical signals, with a faster switching speed and a larger optical switch extinction ratio. The present invention can ultimately achieve the advantages of small size (can reach 1mm size under 1550nm wavelength infrared light), high integration, high transmission bandwidth, fast routing (port switching speed ns level) and other effects.

[0047] The multi-wavelength optical transmitter-router of the present invention is realized by hybrid integration and monolithic integration technology. Each semiconductor optical amplifier part is made of III-V semiconductor materials to convert electrons into photons, provide optical gain and amplification functions, and other parts such as wavelength division multiplexers, optical beam splitters, modulators, etc. use silicon, silicon nitride and other materials to achieve low-loss transmission of light. The two materials are integrated into the same chip by end-face coupling or vertical coupling and by monolithic integration technology.

[0048] The device uses a multi-wavelength laser as a light source, and the optical signal it emits is selected and output by a selectable optical beam splitter. Among them, the multi-wavelength laser can realize the simultaneous output of multiple wavelengths, and each wavelength can be loaded with a high-speed modulation signal. The selectable optical beam splitter can split the light and select it to output from different ports. Combining the multi-wavelength laser and the selectable beam splitter can realize the selective output of multiple wavelengths of signals from different ports, where the output wavelength is determined by the multi-wavelength laser and the output port is determined by the selectable optical beam splitter.

[0049] Compared with the background technology, the present invention has the following beneficial effects:

[0050] 1. Each port can realize multi-wavelength output simultaneously, each wavelength can carry high-speed signals, and a single port can achieve higher transmission bandwidth.

[0051] 2. Both the output wavelength and the output port can be switched, so that in the optical interconnection network, any two nodes can be connected with optical signals of any wavelength.

[0052] 3. The switching of wavelength ports is achieved through the switch of semiconductor optical amplifiers, with fast switching speed and simple control method.

[0053] 4. All devices are integrated on the same chip, with high integration and small system size.

[0054] The present invention can be applied to each node in a distributed routing network and used as an optical transmitter-router, and has the advantages of compact structure, large single-link bandwidth, fast switching speed, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 This is a schematic diagram of the system composition structure of Example 1 of the present invention.

[0056] Figure 2 Schematic diagram of the wavelength selection principle of intracavity multi-wavelength laser.

[0057] Figure 3 This is the actual output effect diagram of the intracavity multi-wavelength laser.

[0058] Figure 4 This is the light field distribution diagram on the input side of the N-way optical beam splitter.

[0059] Figure 5 This is the light field distribution diagram on the output side of the N-way optical beam splitter.

[0060] Figure 6 The output port width of the N-way optical splitter after optimization.

[0061] Figure 7 is the loss of each output port of the N-way optical splitter.

[0062] Figure 8 Schematic diagram of the N-way optical beam splitter chip structure design.

[0063] Fig. 9 Select the relationship between the output optical power of the semiconductor optical amplifier and the current for the port.

[0064] Fig.10 This is a schematic diagram of the chip design of Example 1 of the present invention.

[0065] Fig.11 This is a schematic diagram of the system composition structure of Example 2 of the present invention.

[0066] Fig.12 This is a schematic diagram of the system composition structure of Example 3 of the present invention.

[0067] Fig.13 This is a graph showing the relationship between the laser output power and the input current during direct modulation.

[0068] Fig.14 This is a schematic diagram of the system structure using an external modulator.

[0069] In the figure: a multi-wavelength laser array (1), a selectable optical beam splitter (2), an N-way input semiconductor optical amplifier array (3), an N×1 wavelength division multiplexer (4), an output semiconductor optical amplifier array (5), an N-way optical beam splitter (6), a port selection semiconductor optical amplifier array (7), an N-way single-wavelength laser array (8), and an N-way modulator array (9). DETAILED DESCRIPTION

[0070] The present invention will be further described below in conjunction with the accompanying drawings.

[0071] like Figure 1 As shown, the present invention consists of two parts, the first part is a multi-wavelength laser 1, and the second part is a selectable optical beam splitter 2. It is mainly composed of the multi-wavelength laser 1 and the selectable optical beam splitter 2 connected in sequence. The multi-wavelength laser 1 is used to realize the simultaneous output of optical signals of multiple wavelengths, and the selectable optical beam splitter 2 is constructed based on a specially prepared multi-channel semiconductor optical amplifier array structure, which is used to control the output of optical signals from different ports.

[0072] Optical signals of multiple wavelengths are simultaneously output from the multi-wavelength laser 1 to the selectable optical beam splitter 2, and then the multiple wavelengths in the optical signal are output from different ports. The multi-wavelength laser 1 can achieve the simultaneous output of N wavelengths of laser light, and its output wavelength can be selected. The selectable optical beam splitter 2 can divide the input light into N paths, and the multi-wavelength laser signal can be selectively output from different ports.

[0073] The multi-wavelength laser 1 adopts an intracavity laser structure, and can be mainly composed of an N-way input semiconductor optical amplifier array 3 based on a multi-way semiconductor optical amplifier array structure, an N×1 wavelength division multiplexer 4 and an output semiconductor optical amplifier 5 connected in sequence, each output port of the N-way input semiconductor optical amplifier array 3 is connected to each input port of the N×1 wavelength division multiplexer 4 in a one-to-one correspondence, the output port of the N×1 wavelength division multiplexer 4 is connected to the input port of the output semiconductor optical amplifier 5, and the output port of the output semiconductor optical amplifier 5 is connected to the input port of the N-way optical beam splitter 6 of the selectable optical beam splitter 2; light of different wavelengths has different losses when transmitted from any input port of the N×1 wavelength division multiplexer 4 to the output port, among which only one specific wavelength of light has the lowest loss, and this wavelength is the working wavelength of the input port.

[0074] A semiconductor optical amplifier in the N-way input semiconductor optical amplifier array 3, an N×1 wavelength division multiplexer 4 and an output semiconductor optical amplifier 5 form an optical resonant cavity, in which optical gain is provided by two semiconductor optical amplifiers, and the light of the port working wavelength corresponding to the N×1 wavelength division multiplexer 4 has the minimum transmission loss, and the light of the working wavelength can realize laser lasing and output a single wavelength optical signal of the wavelength. The N semiconductor optical amplifiers in the N-way semiconductor optical amplifier array 3 can realize multi-wavelength laser output of N wavelengths. The N-way input semiconductor optical amplifier array 3 performs optical switch control on the output N-way wavelength optical signals, and the output semiconductor optical amplifier 5 compensates for the loss generated by the N×1 wavelength division multiplexer 4 in the resonant cavity to increase the laser output power, and outputs it to the selectable optical beam splitter 2.

[0075] The multi-wavelength laser 1 can also be mainly composed of N-channel single-wavelength laser arrays 8 and N×1 wavelength division multiplexers 4 connected in sequence, each output port of the N-channel single-wavelength laser array 8 is connected to each input port of the N×1 wavelength division multiplexer 4 in a one-to-one correspondence, and the output port of the N×1 wavelength division multiplexer 4 is connected to the input port of the N-channel optical beam splitter 6 of the selectable optical beam splitter 2;

[0076] N optical signals of wavelengths are simultaneously output from the N single-wavelength laser arrays 8 , and then input into the N×1 wavelength division multiplexer 4 , combined into one channel through wavelength division multiplexing, and then output to the selectable optical beam splitter 2 .

[0077] The N-channel single-wavelength laser array 8 is composed of a plurality of single-wavelength lasers, each of which emits an optical signal of one wavelength, and each single-wavelength laser emits an optical signal of a different wavelength.

[0078] The selectable optical beam splitter 2 is mainly composed of an N-way optical beam splitter 6 and a port selection semiconductor optical amplifier array 7 based on a multi-way semiconductor optical amplifier array structure connected in sequence. The input port of the N-way optical beam splitter 6 is connected to the output port of the multi-wavelength laser 1, and each output port of the N-way optical beam splitter 6 is connected one-to-one with each input port of the N-way input semiconductor optical amplifier array 3.

[0079] The N-way optical beam splitter 6 is designed with a star coupler structure. The optical signal output by the multi-wavelength laser enters the N-way optical beam splitter 6, and after beam splitting processing, it is divided into N-way optical signals and input into each port of the port selection semiconductor optical amplifier array 7. Each optical signal is switched by the corresponding semiconductor optical amplifier in the port selection semiconductor optical amplifier array 7, thereby realizing the function of routing the multi-wavelength optical signal to different ports.

[0080] The N-way optical beam splitter 6 is realized by a star coupler. After the light is expanded in the free transmission area, it is coupled into different waveguides. By optimizing the width of the waveguide, a uniform light splitting effect can be achieved. A semiconductor optical amplifier array 7 is set at the connection port after the N-way optical beam splitter. For the port selection semiconductor optical amplifier, when current is applied to it, the light passing through the semiconductor optical amplifier is gained, and the corresponding port can output an optical signal. When no current is applied to it, the light passing through the semiconductor optical amplifier is lost, and the corresponding port cannot output an optical signal. In this way, by selecting to apply current to different semiconductor optical amplifiers in the port selection semiconductor optical amplifier array 7, the selective output of optical signals from different ports can be achieved.

[0081] The N-channel input semiconductor optical amplifier array 3 and the port selection semiconductor optical amplifier array 7 are both multi-channel semiconductor optical amplifier arrays made of III-V semiconductor materials.

[0082] The multi-channel semiconductor optical amplifier array is made of III-V semiconductor materials and is used to convert electrons into photons to provide optical gain, switching and active laser functions. In addition to the multi-channel semiconductor optical amplifier array, other N×1 wavelength division multiplexer 4, output semiconductor optical amplifier 5, N-channel single-wavelength laser array 8, N-channel optical beam splitter 6, N-channel modulator array 9 and other devices use passive materials such as silicon and silicon nitride. Such materials are used to achieve low-loss transmission of light; the two materials are integrated on the same chip through end-face coupling or vertical coupling, so that the multi-wavelength optical transmitter-router of the present invention is realized through hybrid integration technology.

[0083] Each wavelength emitted by the multi-wavelength laser can be loaded with a high-speed signal by means of direct modulation, and specifically, can be loaded with a high-speed signal by means of an integrated N-channel modulator array 9 .

[0084] An N-channel modulator array 9 is arranged in series between the multi-wavelength laser 1 and the selectable optical beam splitter 2. The N-channel modulator array 9 is used to modulate each wavelength of the passing optical signal in a direct modulation manner to load a high-speed signal.

[0085] The multi-channel semiconductor optical amplifier array is mainly manufactured in the following manner:

[0086] First, a wafer structure is made, which is mainly composed of a substrate, a lower cladding, an active layer and an upper cladding from bottom to top. The refractive index of the active layer material is higher than that of the upper cladding and the lower cladding materials. The manufacturing process is as follows:

[0087] Then, the design pattern is transferred to the surface of the upper cladding layer by photolithography, and the upper cladding layer is removed by wet etching or dry etching, so that the upper cladding layer forms a ridge waveguide, and the substrate, the lower cladding layer, and the active layer remain unetched and have the same size, and a plurality of ridge waveguides are directly prepared and formed according to the design pattern, that is, the upper cladding layer is etched at multiple locations, and etching grooves are formed at the etched locations, and a plurality of strip structures are formed at the unetched locations as ridge waveguides, and then the lower cladding layer and the active layer between adjacent ridge waveguides are overetched to form deep etching grooves; thereby, the ridge waveguide of each upper cladding layer is used as a semiconductor optical amplifier, and deep etching grooves are set between adjacent semiconductor optical amplifiers to separate them;

[0088] Next, a silicon oxide insulating layer is deposited on the upper cladding layer and the exposed active layer. A window is then opened in the silicon oxide insulating layer and a P-type electrode connected to the upper cladding layer is made. Finally, the back side of the substrate is thinned and polished, and an N-type electrode connected to the substrate is made on the back side.

[0089] Each semiconductor optical amplifier in the multi-channel semiconductor optical amplifier array has the same waveguide length and is integrally manufactured in an array manner with the same spacing. An independent P-type electrode is manufactured on each semiconductor optical amplifier, and all semiconductor optical amplifiers use a common N-type electrode.

[0090] In this way, current is applied independently to the active layer of each semiconductor optical amplifier, thereby amplifying the optical signal passing through the semiconductor optical amplifier to provide optical gain and switching effect; since the design and manufacturing process of each semiconductor optical amplifier are the same, their performance is similar and the same optical amplification effect can be achieved. In addition, deep etched grooves can be used to separate adjacent semiconductor optical amplifiers to reduce current crosstalk and thermal crosstalk.

[0091] The semiconductor optical amplifier in the input semiconductor optical amplifier array 3 realizes the light source lasing effect by using the semiconductor light amplification function. When the applied current is greater than the threshold current, the light amplification effect causes the particle number inversion in the resonant cavity to realize laser lasing.

[0092] The semiconductor optical amplifiers in the port selection semiconductor optical amplifier array 7 use the semiconductor optical amplification function to achieve a switching effect. When the current applied to the semiconductor optical amplifier is less than or equal to the threshold current, the optical gain provided by each semiconductor optical amplifier is less than the loss, and the input optical signal is shown as an absorption effect;

[0093] When the current applied to the semiconductor optical amplifier is greater than the threshold current, the optical gain provided by each semiconductor optical amplifier is greater than the loss, and the input optical signal is amplified. Thus, the above-mentioned combined preparation acts as an optical switch.

[0094] The lower cladding and upper cladding are made of binary compound materials, such as InP, where the upper cladding material is P-type doped and the lower cladding material is N-type doped; the active layer is made of multi-quantum well materials composed of quaternary compound materials, such as InGaAsP, and the refractive index of the active layer material is higher than that of the upper and lower cladding materials, so that light is confined to the active layer for transmission. After applying current, the active layer material can convert electrons into photons to provide optical gain.

[0095] In the optical transmitter-router of the present invention, each semiconductor optical amplifier is made of active materials that provide optical gain and optical amplification functions, and the wavelength division multiplexer, optical beam splitter, modulator and other parts are made of passive materials with low optical loss. Each part can be integrated on the same chip through monolithic integration technology or hybrid integration technology to minimize the size.

[0096] In monolithic integration technology, all parts of the device are made on the same Group III-V semiconductor material, among which the active layer of the semiconductor optical amplifier part is quantum well material. After the materials for making other parts undergo processes such as quantum well intermixing, docking regrowth, and biased quantum well, their quantum well energy bands change, and the absorption of light at the working wavelength decreases, turning them into passive materials.

[0097] In hybrid integration technology, the semiconductor optical amplifier is partially made on III-V semiconductor materials, and the other parts are made on silicon-based materials such as silicon on insulator (SOI) and silicon nitride, which can achieve low-loss transmission of light. The two materials are integrated into the same chip through end-face coupling or vertical coupling, achieving high integration. Example 1

[0098] The basic structural diagram of the present invention is as follows Figure 1 As shown. Its structure consists of two parts: a multi-wavelength laser 1 and a selectable optical beam splitter 2. The multi-wavelength laser 1, as a light source, can provide N-way multi-wavelength laser output. The selectable optical beam splitter 2 can split the light of the light source into N beams and select the output from different ports.

[0099] In Example 1, the multi-wavelength laser 1 is implemented as an intracavity multi-wavelength laser, and its structure is as follows: Figure 1 As shown, it includes an N-channel input semiconductor optical amplifier array 3, an N×1 wavelength division multiplexer 4, and an output semiconductor optical amplifier 5.

[0100] The N-channel input semiconductor optical amplifier array 3 is composed of N semiconductor optical amplifiers, wherein one end of each semiconductor optical amplifier is a high reflection surface, and the other end is connected to the input side of the wavelength division multiplexer.

[0101] The N×1 wavelength division multiplexer 4 has N ports on the input side and 1 port on the output side. For different wavelengths input from the input port, the loss of the output port is as follows: Figure 2 As shown, there is a minimum loss wavelength between each input port and output port, which is the working wavelength of the input and output port. The N×1 wavelength division multiplexer 4 can be realized by etching a diffraction grating or an arrayed waveguide grating.

[0102] One end of the output semiconductor optical amplifier 5 is connected to the output side of the wavelength division multiplexer, and the other end is an output end connected to the selectable optical beam splitter 2 .

[0103] One semiconductor optical amplifier in the N-way input semiconductor optical amplifier array 3, the N×1 wavelength division multiplexer 4 and the output semiconductor optical amplifier 5 together form an optical resonant cavity. In the optical resonant cavity, there are two semiconductor optical amplifiers. Applying current to the semiconductor optical amplifiers can convert electrons into photons. After the applied current reaches a threshold, the resonant cavity meets the particle inversion condition and can achieve laser output. For this resonant cavity, since the N×1 wavelength division multiplexer 4 is in the resonant cavity, the losses of different wavelengths in the resonant cavity are different. Among them, the light corresponding to the working wavelength of the wavelength division multiplexer between the input and output ports also has the lowest loss in the resonant cavity. The laser threshold of this wavelength is lower and it is easier to lasing, so the laser can achieve single wavelength output.

[0104] In this embodiment, the N×1 wavelength division multiplexer 4 is a passive device, which will introduce certain optical losses and affect the laser output power. The output semiconductor optical amplifier 5 compensates for the losses generated by the N×1 wavelength division multiplexer 4 in the resonant cavity to increase the laser output power.

[0105] Since the N-way input semiconductor optical amplifier array 3 has N input semiconductor optical amplifiers, a total of N resonant cavities can be formed, each of which corresponds to a wavelength output, so the multi-wavelength laser formed in this way can achieve N wavelength outputs. Each wavelength corresponds to the working wavelength of each input port of the wavelength division multiplexer.

[0106] Taking an 8-channel multi-wavelength laser as an example, the laser output corresponding to 8 wavelengths is as follows: Figure 3 As shown, since the wavelength of the multi-wavelength laser is determined by the operating wavelengths between the input and output ports of the intracavity N×1 wavelength division multiplexer 4, its output wavelength is automatically aligned, has good stability, and does not require an additional wavelength control method.

[0107] The selectable optical beam splitter 2 is composed of an N-way optical beam splitter 6 and a port selection semiconductor optical amplifier array 7. The input end of the N-way optical beam splitter 2 is connected to the multi-wavelength laser 1, and the light emitted by the multi-wavelength laser can be divided into N beams, each of which has a similar intensity.

[0108] The N-way optical beam splitter 6 is implemented as a star coupler. For the star coupler, the input light is continuously widened due to diffraction during the transmission of the input light in the free transmission zone. On the input side, the light input into the waveguide is generally Gaussian distributed. Taking the input waveguide with a width of 2 μm as an example, the intensity distribution of the input light field is as follows: Figure 4 As shown. After passing through a 400μm long free transmission zone, the light field distribution of the input light reaching the output side is as follows Figure 5 As shown in the figure, the light field still approximately satisfies the Gaussian distribution, with a stronger light intensity in the center and a weaker light intensity in the edge. In order to make the light intensity entering each output port similar, the position and width of the output port need to be optimized, so that the output port near the center has a smaller width and relatively less light is coupled into it, and the output port near the edge has a larger width and relatively more light is coupled into it, so as to achieve the effect of beam averaging.

[0109] When designing the output port, you need to first design the center port width to be the minimum, which generally corresponds to the minimum width of the single-mode waveguide, calculate the intensity of the light coupled into it, and then calculate the width of the waveguides on both sides in turn, so that the intensity of the light coupled into each waveguide is similar to that of the center waveguide. Taking a 1×16 beam splitter as an example, the calculated widths of each output port are as follows: Figure 6 After the input light is split, the relative intensity of the light coupled into each port is shown as Figure 7 As shown in the figure, it can be seen that the optical loss of each port after splitting is similar, thus realizing an N-way optical beam splitter with good performance. The chip design of the N-way optical beam splitter designed in this way is as follows Figure 8 As shown, this design has a compact structure, low optical loss and good splitting performance.

[0110] The output end of the N-way optical beam splitter 6 is connected to the port selection semiconductor optical amplifier array 7, and the port selection semiconductor optical amplifier array determines that the light is output from one or more ports.

[0111] The port selection semiconductor optical amplifier array 7 is composed of N semiconductor optical amplifiers. For a semiconductor optical amplifier, when the applied current is less than or equal to the threshold current, it has an absorption effect on the input light. After the applied current is greater than the threshold current, it can have an amplification effect on the input light. In this way, by controlling the current of the semiconductor optical amplifier, an optical switching effect can be achieved, and it is selected whether the light of the port can be output, thereby achieving a port selection effect. Since the semiconductor optical amplifier array is in an absorption state and an amplification state before and after the current is applied, its switching state has a higher extinction ratio. When the semiconductor optical amplifier works in the amplification mode, the output light is amplified, and the output power can be further improved. Since the semiconductor optical amplifier responds quickly to the current, a fast switching effect can be achieved. Under the same input power, the relationship between the output power of the semiconductor optical amplifier and the current is as follows: Fig. 9 shown.

[0112] Fig.10 This is a schematic diagram of a chip design in Example 1 of the present invention. In the figure, the wavelength division multiplexer adopts an etched diffraction grating. By utilizing the wavelength selection characteristics of the grating, the light of a specific wavelength incident at the input port is reflected by the grating tooth surface and interference imaging is formed at the output port. Different input and output ports correspond to different imaging wavelengths, and the wavelength has the lowest propagation loss. The input semiconductor optical amplifier array 3 is connected to the etched diffraction grating input port, and one end of the output semiconductor optical amplifier 5 is connected to the etched diffraction grating output port. The other end is connected to the input end of the N-way optical beam splitter 6, and the output end of the N-way optical beam splitter 6 is connected to the port selection semiconductor optical amplifier array 7. Example 2

[0113] In Embodiment 2, the multi-wavelength laser 1 is implemented as a combination of a single-wavelength laser array and a wavelength division multiplexer. Fig.11 This is a schematic diagram of the structural composition of Example 2 of the present invention.

[0114] In Example 2, the multi-wavelength laser 1 is composed of an N-channel single-wavelength laser array 8 and an N×1 wavelength division multiplexer 4. One laser in the N-channel single-wavelength laser array 8 can realize the emission of a single-wavelength laser, and the N single-wavelength lasers can realize the lasing of N wavelengths of light, and these N wavelengths correspond to the N minimum loss wavelengths of the N×1 wavelength division multiplexer 5. Each single-wavelength laser in the N-channel single-wavelength laser array 8 is connected to the input port corresponding to the N×1 wavelength division multiplexer 5, and the N×1 wavelength division multiplexer 5 can be used to combine the various wavelengths into one beam for output. Selecting different single wavelengths can realize the selective output of lasers of different wavelengths.

[0115] In this embodiment, the N×1 wavelength division multiplexer 4 combines N wavelength optical signals into one beam for output only by wavelength division multiplexing, and its loss has little effect on the laser power, and there is no need to add an output semiconductor optical amplifier for compensation.

[0116] The implementation method of the selectable optical beam splitter 2 in the second embodiment is the same as that in the first embodiment. Example 3

[0117] In Embodiment 3, the selectable optical beam splitter is implemented as a 1×N optical switch. Fig.12 This is a schematic diagram of the structural composition of Example 3 of the present invention.

[0118] In Example 3, the optical beam splitter can be implemented using a 1×N optical switch. The 1×N optical switch is formed by cascading multiple 1×2 optical switch units, and each 1×2 optical switch can split the light into 2 paths, each of which controls the switch of the optical path through a Mach-Zehnder interference structure. By cascading multiple 1×2 optical switch unit arrays, the number of 1×2 switch units in each 1×2 optical switch unit array is twice that of the previous column, and the last 1×2 optical switch unit array has N / 2 1×2 switch units to achieve N port outputs. With multiple 1×2 optical switches working together, the input light can be split and selected to be output from different ports. 1×N optical switches are generally made on silicon-based semiconductor materials such as silicon on insulator, silicon nitride, silicon oxide SiO2, etc. The manufacturing process is mature and can achieve a uniform optical beam splitting effect.

[0119] The implementation method of the multi-wavelength laser 1 in the third embodiment is the same as that in the first embodiment.

[0120] In the optical transmitter-router of the above three embodiments of the present invention, a high-speed signal can be independently loaded onto an optical signal of each wavelength to achieve parallel propagation of multiple signals of different wavelengths.

[0121] One way to load high-speed signals is direct modulation. For semiconductor lasers, changing the applied current can change the output power, which can achieve the effect of converting electrical signals into optical signals, thereby loading high-speed modulated signals. The output power of semiconductor lasers changes with the applied current. Fig.13 As shown, after the current reaches the laser output threshold, its output power changes linearly with the current, which is suitable for loading high-speed signals. For Example 1, each semiconductor optical amplifier in the N-way input semiconductor optical amplifier array 3 can be independently used as a direct modulator to achieve modulation of the corresponding wavelength optical signal. For Example 2, each single-wavelength laser in the N-way single-wavelength laser array 8 can be directly modulated to load high-speed signals at the corresponding wavelength.

[0122] Another way to load high-speed signals is to use an external modulator array, such as Fig.14 As shown, an N-channel modulator array 9 is added between the multi-wavelength laser 1 and the selectable optical beam splitter 2. The N-channel modulator array 9 is composed of N modulators, each of which can modulate light of different wavelengths and load high-speed signals. The N-channel modulator array 9 can be implemented in the form of a micro-ring modulator, and the corresponding working wavelength can be changed by controlling the radius of the ring in the micro-ring modulator. By making the working wavelengths of the N modulators correspond to the output wavelength of the multi-wavelength laser 1, the effect of loading a high-speed signal separately on the optical signal of each wavelength can be achieved.

[0123] All structures of the semiconductor multi-wavelength optical transmitter-router are integrated on the same chip. Among them, the N-way input semiconductor optical amplifier array 3, the output semiconductor optical amplifier array 5, the port selection semiconductor optical amplifier array 7, and the N-way single-wavelength laser array 8 can all be made of active semiconductor materials with the same gain. The N×1 wavelength division multiplexer 4, the N-way optical beam splitter 6, and the N-way modulator array 9 are made of passive semiconductor materials with low optical loss. There are two ways to integrate the chip. One is monolithic integration, in which all materials are III-V semiconductor materials. Quantum well hybridization, end-face docking, selective epitaxy and other technologies are used to make different regions on the same chip have different characteristics. The other way is hybrid integration, in which the active semiconductor material is a III-V semiconductor material, and the passive semiconductor material is a silicon-based semiconductor material such as silicon on insulator SOI, silicon nitride Si3N4, silicon oxide SiO2, etc. The two semiconductor materials are integrated into the same chip by end-face coupling or grating coupling.

[0124] The above specific implementations are used to explain the present invention, rather than to limit the present invention. Any modifications and changes made to the present invention within the spirit of the present invention and the protection scope of the claims shall fall within the protection scope of the present invention. The above description is only a preferred implementation of the present invention, so any equivalent changes or modifications made according to the structure, features and principles described in the scope of the patent application of the present invention are included in the scope of the patent application of the present invention.

Claims

1. An optical transmitter-router based on a multi-wavelength laser and a selectable optical beam splitter, characterized in that: The invention mainly comprises a multi-wavelength laser (1) and a selectable optical beam splitter (2) connected in sequence, wherein the multi-wavelength laser (1) is used to realize the simultaneous output of optical signals of multiple wavelengths, and the selectable optical beam splitter (2) is constructed based on a multi-channel semiconductor optical amplifier array structure and is used to control the output of optical signals from different ports; The multi-wavelength laser (1) is mainly composed of an N-way input semiconductor optical amplifier array (3) based on a multi-way semiconductor optical amplifier array structure, an N×1 wavelength division multiplexer (4), and an output semiconductor optical amplifier (5) connected in sequence, and each output port of the N-way input semiconductor optical amplifier array (3) is connected to each port of the N×1 wavelength division multiplexer (4) in a one-to-one correspondence; An optical resonant cavity is formed by a semiconductor optical amplifier in the N-channel input semiconductor optical amplifier array (3), an N×1 wavelength division multiplexer (4) and an output semiconductor optical amplifier (5). In the optical resonant cavity, optical signals of N wavelengths are simultaneously output from the N-channel input semiconductor optical amplifier array (3). At the same time, the N-channel input semiconductor optical amplifier array (3) performs optical switch control on the outputted N-channel wavelength optical signals. The optical signal of each wavelength is a single wavelength optical signal of the working wavelength at the input port of the N×1 wavelength division multiplexer (4). The optical signal is then input into the N×1 wavelength division multiplexer (4) to select the output wavelength for wavelength division multiplexing and beam combining into one channel for processing. The optical signal is then input into the output semiconductor optical amplifier (5) for loss compensation and then used for output to the selectable optical beam splitter (2). The selectable optical beam splitter (2) is mainly composed of N-way optical beam splitters (6) and a port selection semiconductor optical amplifier array (7) based on a multi-way semiconductor optical amplifier array structure, which are connected in sequence. Each output port of the N-way optical beam splitter (6) is connected to each port of the N-way input semiconductor optical amplifier array (3) in a one-to-one correspondence. The N-way optical beam splitter (6) is designed with a star coupler structure. One optical signal of different wavelengths is input to the N-way optical beam splitter (6) and is split into optical signals of different wavelengths after beam splitting. Each optical signal is switched by a corresponding semiconductor optical amplifier in the port selection semiconductor optical amplifier array (7), thereby realizing the function of routing multi-wavelength optical signals to different ports.

2. The optical transmitter-router based on a multi-wavelength laser and a selectable optical beam splitter according to claim 1, characterized in that: The multi-wavelength laser (1) is mainly composed of N-channel single-wavelength laser arrays (8) and N×1 wavelength division multiplexers (4) connected in sequence, and each output port of the N-channel single-wavelength laser array (8) is connected to each port of the N×1 wavelength division multiplexer (4) in a one-to-one correspondence; optical signals of N wavelengths are simultaneously output from the N-channel single-wavelength laser array (8), then input into the N×1 wavelength division multiplexer (4), combined into one channel through wavelength division multiplexing, and then output to the selectable optical beam splitter (2).

3. The optical transmitter-router based on a multi-wavelength laser and a selectable optical beam splitter according to claim 1, characterized in that: The N-channel input semiconductor optical amplifier array (3) / port selection semiconductor optical amplifier array (7) both adopt multi-channel semiconductor optical amplifier arrays.

4. The optical transmitter-router based on a multi-wavelength laser and a selectable optical beam splitter according to claim 3, characterized in that: The multi-channel semiconductor optical amplifier array is made of III-V semiconductor materials, and other devices except the multi-channel semiconductor optical amplifier array are made of passive materials such as silicon and silicon nitride.

5. The optical transmitter-router based on a multi-wavelength laser and a selectable optical beam splitter according to claim 1, characterized in that: An N-channel modulator array (9) is arranged between the multi-wavelength laser (1) and the selectable optical beam splitter (2), and the N-channel modulator array (9) is used to modulate each wavelength of the passing optical signal in a direct modulation manner.

6. The optical transmitter-router based on a multi-wavelength laser and a selectable optical beam splitter according to claim 3, characterized in that: The multi-channel semiconductor optical amplifier array is mainly manufactured in the following manner: First, a wafer structure is prepared which is mainly composed of a substrate, a lower cladding layer, an active layer and an upper cladding layer in order from bottom to top, wherein the refractive index of the active layer material is higher than the refractive index of the upper cladding layer and the lower cladding layer material; Then, the design pattern is transferred to the surface of the upper cladding layer by photolithography, and the upper cladding layer is removed by wet etching or dry etching to form a ridge waveguide in the upper cladding layer, and a plurality of ridge waveguides are directly prepared according to the design pattern, and then the lower cladding layer and the active layer between adjacent ridge waveguides are etched to form deep etched grooves; thereby, each ridge waveguide of the upper cladding layer is used as a semiconductor optical amplifier, and deep etched grooves are set between adjacent semiconductor optical amplifiers to separate them; Next, a silicon oxide insulating layer is deposited on the upper cladding layer and the exposed active layer. A window is then opened in the silicon oxide insulating layer and a P-type electrode connected to the upper cladding layer is made. Finally, an N-type electrode connected to the substrate is made after thinning and polishing the back side of the substrate.

7. The optical transmitter-router based on a multi-wavelength laser and a selectable optical beam splitter according to claim 6, characterized in that: Each semiconductor optical amplifier in the multi-channel semiconductor optical amplifier array has the same waveguide length and is integrally manufactured in an array manner with the same spacing. An independent P-type electrode is manufactured on each semiconductor optical amplifier, and all semiconductor optical amplifiers use a common N-type electrode. A current is applied independently to each semiconductor optical amplifier, thereby providing a light source lasing and switching function for the optical signal passing through the semiconductor optical amplifier: For the semiconductor optical amplifier in the N-channel input semiconductor optical amplifier array (3): When the applied current is greater than the threshold current, light amplification occurs, causing the number of particles in the resonant cavity to be reversed, thus achieving laser lasing. When the applied current is less than or equal to the threshold current, the light amplification effect is lower than the loss in the optical resonant cavity, the number of particles in the optical resonant cavity cannot be inverted, and the optical resonant cavity cannot achieve laser lasing; For the semiconductor optical amplifier in the port selection semiconductor optical amplifier array (7): When the applied current is less than or equal to the threshold current, the optical gain provided by each semiconductor optical amplifier is less than the loss, and the input optical signal is absorbed in the optical resonant cavity; When the applied current is greater than the threshold current, the optical gain provided by each semiconductor optical amplifier is greater than the loss, and the input optical signal is conducted in the optical resonant cavity.

8. The optical transmitter-router based on a multi-wavelength laser and a selectable optical beam splitter according to claim 6, characterized in that: The lower cladding and upper cladding of the multi-channel semiconductor optical amplifier array are made of binary compound materials, wherein the upper cladding material is P-type doped and the lower cladding material is N-type doped; The active layer adopts a multi-quantum well material composed of a quaternary compound material.

9. An optical transmitter-router based on a multi-wavelength laser and a selectable optical beam splitter according to any one of claims 1-2 and 4-8, characterized in that: All components of the multi-wavelength laser (1) and the selectable optical beam splitter (2) are integrated on the same chip by means of monolithic integration or hybrid integration.

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