Silicon-based large-range tunable external cavity laser

Abstract

The utility model discloses a silicon-based large-range tunable external cavity laser, which comprises two reflection-type semiconductor optical amplifiers with adjacent gain bands, and the two reflection-type semiconductor optical amplifiers are respectively connected to two input ends of an optical switch through a silicon-based light spot size converter. One output end of the optical switch is connected with the input end of the first micro-ring filter through the phase shifter, the output end of the first micro-ring filter is connected with the input end of the second micro-ring filter, and the output end of the second micro-ring filter is connected with the input end of the adjustable Sagnac reflector. And the output port of the Sagnac reflector is a laser emitting port. According to the utility model, the reflection type semiconductor optical amplifiers of two adjacent gain wave bands are integrated at the two input ends of the optical switch, so that the gain puffing range of the laser is greatly enlarged, the wavelength range of the laser is expanded, and the loop loss is effectively reduced by utilizing the thermo-optic effect of a silicon substrate.

Description

Technical Field

[0001] The utility model relates to the field of integrated optics of optical communication, in particular to a silicon-based wide-range tunable external cavity laser. Background Art

[0002] In the field of integrated optics, silicon-based photonic devices have developed rapidly in recent years due to their compatibility with CMOS, large refractive index, good thermo-optical and carrier dispersion effects. Due to the material properties of silicon indirect bandgap, silicon-based light sources have always been the main problem affecting their development. At present, external cavity lasers of III-V and silicon-based hybrid integration have become a common technical idea for realizing narrow linewidth tunable lasers.

[0003] The invention patent with application number 201910567777.9 discloses a wavelength-tunable directly modulated silicon-based external cavity laser. The reflective semiconductor optical amplifier of the directly modulated external cavity laser is connected to a phase shifter through a silicon-based spot size converter, and then connected to the input end of a narrow passband filter. The output end of the narrow passband filter is connected to the input end of a micro-ring modulator. The download end of the micro-ring modulator is connected to the input end of a first reflector, and the through end of the micro-ring modulator is connected to a second reflector. The above invention forms a filtering structure through the vernier effect of a narrow passband filter and a micro-ring modulator to obtain a wide tuning range and narrow linewidth laser, and modulate the output light at the same time. However, for the application of silicon-based external cavity lasers in large-capacity wavelength division multiplexing systems, it is necessary to further expand their tunable range. Utility Model Content

[0004] The utility model provides a silicon-based wide-range tunable external cavity laser, which realizes the routing of the internal optical path of the laser through two reflective semiconductor optical amplifiers in adjacent gain bands and an optical switch, thereby realizing the expansion of the tunable range of the external cavity laser, thereby solving the technical problem that the application of silicon-based external cavity lasers in large-capacity wavelength division multiplexing systems requires further expansion of the tunable range.

[0005] In order to achieve the above object, the technical solution of the utility model is implemented as follows:

[0006] A silicon-based wide-range tunable external cavity laser comprises a first reflective semiconductor optical amplifier, a second reflective semiconductor optical amplifier, a first spot size converter, a second spot size converter, an optical switch, a phase shifter, a first microring filter, a second microring filter and an adjustable Sagnac reflector.

[0007] The first spot size converter, the second spot size converter, the optical switch, the phase shifter, the first micro-ring filter, the second micro-ring filter and the adjustable Sagnac reflector are arranged on the same silicon substrate.

[0008] The output end of the first reflective semiconductor optical amplifier is connected to the input end of the first spot size converter, the output end of the first spot size converter is connected to one input end of the optical switch, the output end of the second reflective semiconductor optical amplifier is connected to the input end of the second spot size converter, the output end of the second spot size converter is connected to another input end of the optical switch, one output end of the optical switch is connected to the input end of the first microring filter through a phase shifter, the output end of the first microring filter is connected to the input end of the second microring filter, the output end of the second microring filter is connected to the input end of the adjustable Sagnac reflector, and the output port of the adjustable Sagnac reflector is a laser output port.

[0009] The first reflective semiconductor optical amplifier and the second reflective semiconductor optical amplifier both have a high reflectivity end (reflectivity>90%) at one end and a low reflectivity end (reflectivity≤0.005%) at the other end, and the low reflectivity end is the output end of the first reflective semiconductor optical amplifier and the second reflective semiconductor optical amplifier.

[0010] The first spot size converter and the second spot size converter both adopt a structure including an inverted cone coupler or a suspended waveguide coupler.

[0011] The optical switch is composed of an equal-arm Mach-Zehnder interferometer (MZI).

[0012] The phase shifter is a thermo-optical phase shifter.

[0013] The first micro-ring filter and the second micro-ring filter have different radii.

[0014] The first micro-ring filter and the second micro-ring filter are both narrow passband filters.

[0015] The adjustable Sagnac reflector is composed of a Mach-Zehnder interferometer and a U-shaped waveguide. A thermo-optical phase shifter is integrated on one arm of the Mach-Zehnder interferometer, and the coupling ratios of the input and output couplers are both 50:50.

[0016] The first spot size converter, the second spot size converter, the optical switch, the phase shifter, the first microring filter, the second microring filter and the adjustable Sagnac reflector can all be implemented by silicon waveguides.

[0017] The first reflective semiconductor optical amplifier, the second reflective semiconductor optical amplifier and the silicon chip are aligned by a method including butt coupling, flip-chip or bonding.

[0018] The wavelength tunable function of the laser is achieved by thermal tuning of a narrow passband filter composed of a first microring filter and a second microring filter and an adjustable Sagnac reflector, and the expansion of the tunable range is achieved by optical path switching of two adjacent gain bands of reflective semiconductor optical amplifiers (a first reflective semiconductor optical amplifier 101 and a second reflective semiconductor optical amplifier 102).

[0019] Compared with the prior art, the utility model has the following beneficial effects:

[0020] 1. The utility model integrates reflective semiconductor optical amplifiers of two adjacent gain bands at two input ends of an optical switch, thereby greatly increasing the gain range of the laser and thus extending the tunable range of the external cavity laser.

[0021] 2. The utility model utilizes the thermo-optical effect of silicon, which can effectively reduce the circuit loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 This is a schematic diagram of an embodiment of the silicon-based widely tunable external cavity laser of the utility model.

[0024] In the figure, 101 is a first reflective semiconductor optical amplifier, 102 is a second reflective semiconductor optical amplifier, 103 is a first spot size converter, 104 is a second spot size converter, 105 is an optical switch, 106 is a phase shifter, 107 is a first micro-ring filter, 108 is a second micro-ring filter, and 109 is an adjustable Sagnac reflector. DETAILED DESCRIPTION

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

[0026] like Figure 1As shown, the silicon-based widely tunable external cavity laser includes a first reflective semiconductor optical amplifier 101, a second reflective semiconductor optical amplifier 102, a first spot size converter 103, a second spot size converter 104, an optical switch 105, a phase shifter 106, a first microring filter 107, a second microring filter 108 and an adjustable Sagnac reflector 109.

[0027] The first spot size converter 103, the second spot size converter 104, the optical switch 105, the phase shifter 106, the first micro-ring filter 107, the second micro-ring filter 108 and the adjustable Sagnac reflector 109 are arranged on the same silicon substrate.

[0028] The output end of the first reflective semiconductor optical amplifier 101 is connected to the input end of the first spot size converter 103, the output end of the first spot size converter 103 is connected to one input end of the optical switch 105, the output end of the second reflective semiconductor optical amplifier 102 is connected to the input end of the second spot size converter 104, the output end of the second spot size converter 104 is connected to another input end of the optical switch 105, one output end of the optical switch 105 is connected to the input end of the first micro-ring filter 107 through the phase shifter 106, the output end of the first micro-ring filter 107 is connected to the input end of the second micro-ring filter 108, the output end of the second micro-ring filter 108 is connected to the input end of the adjustable Sagnac reflector 109, and the output port 110 of the adjustable Sagnac reflector 109 is a laser output port.

[0029] In this embodiment, the optical switch 105 is a 2×2 optical switch.

[0030] The first reflective semiconductor optical amplifier 101 and the second reflective semiconductor optical amplifier 102 both have a high reflectivity end (reflectivity>90%) at one end and a low reflectivity end (reflectivity≤0.005%) at the other end. The low reflectivity end is the output end of the first reflective semiconductor optical amplifier 101 and the second reflective semiconductor optical amplifier 102.

[0031] Furthermore, the first spot size converter 103, the second spot size converter 104, the optical switch 105, the phase shifter 106, the first microring filter 107, the second microring filter 108 and the adjustable Sagnac reflector 109 can all be implemented by silicon waveguides. The first reflective semiconductor optical amplifier 101, the second reflective semiconductor optical amplifier 102 and the silicon chip are aligned by docking coupling. In actual implementation, they can also be aligned by flip-chip, bonding and the like.

[0032] Furthermore, the first spot size converter 103 and the second spot size converter 104 are both inverted cone couplers. In actual implementation, other structures with spot size conversion function such as cone couplers may also be used.

[0033] Furthermore, by switching the optical switch 105 , the on and off states of the first reflective semiconductor optical amplifier 101 and the second reflective semiconductor optical amplifier 102 are quickly adjusted.

[0034] Furthermore, the optical switch 105 is composed of an equal-arm Mach-Zehnder interferometer (MZI), and uses silicon-based thermo-optical effect to achieve optical path switching.

[0035] Furthermore, the phase shifter 106 is a thermo-optical phase shifter.

[0036] Furthermore, the radius of the first micro-ring filter 107 and the radius of the second micro-ring filter 108 are slightly different, forming a vernier filtering effect.

[0037] Furthermore, by adjusting the phase shifter 106, the first microring filter 107 and the second microring filter 108, the resonant wavelength of the laser Fabry-Perot cavity and the vernier effect are aligned to achieve mode selection, thereby achieving continuous adjustment of the laser output wavelength.

[0038] Further, the free spectral ranges of the first microring filter 107 and the second microring filter 108 are:

[0039]

[0040] Where λ is the resonant wavelength of the microring, Δλ is the wavelength interval between adjacent resonant peaks, and n g is the waveguide group refractive index of the microring, L r is the circumference of the microannulus.

[0041] The first micro-ring filter 107 and the second micro-ring filter 108 are both narrow passband filters. The free spectral range FSR1 of the first micro-ring filter 107 and the free spectral range FSR2 of the second micro-ring filter 108 are slightly different, and a vernier effect filter can be formed. 滤波 for:

[0042]

[0043] The filter resonant wavelengths can be adjusted individually via their respective phase shifters.

[0044] Specifically, the wavelength tunable function of the laser is achieved by thermal tuning of a narrow passband filter composed of a first microring filter 107 and a second microring filter 108 and an adjustable Sagnac reflector 109, and the expansion of the tunable range is achieved by optical path switching of two adjacent gain bands of reflective semiconductor optical amplifiers (a first reflective semiconductor optical amplifier 101 and a second reflective semiconductor optical amplifier 102).

[0045] Furthermore, the adjustable Sagnac reflector 109 is composed of a Mach-Zehnder interferometer (MZI) and a U-shaped waveguide, a thermo-optical phase shifter is integrated on one arm of the Mach-Zehnder interferometer, and the coupling ratios of the input and output couplers are both 50:50.

[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

Claims

1. A silicon-based widely tunable external cavity laser, characterized in that: It comprises a first reflective semiconductor optical amplifier (101), a second reflective semiconductor optical amplifier (102), a first spot size converter (103), a second spot size converter (104), an optical switch (105), a phase shifter (106), a first microring filter (107), a second microring filter (108), and an adjustable Sagnac reflector (109); The first spot size converter (103), the second spot size converter (104), the optical switch (105), the phase shifter (106), the first micro-ring filter (107), the second micro-ring filter (108) and the adjustable Sagnac reflector (109) are arranged on the same silicon substrate; The output end of the first reflective semiconductor optical amplifier (101) is connected to the input end of the first spot size converter (103), the output end of the first spot size converter (103) is connected to an input end of an optical switch (105), the output end of the second reflective semiconductor optical amplifier (102) is connected to the input end of the second spot size converter (104), the output end of the second spot size converter (104) is connected to another input end of the optical switch (105), one output end of the optical switch (105) is connected to the input end of the first micro-ring filter (107) through a phase shifter (106), the output end of the first micro-ring filter (107) is connected to the input end of the second micro-ring filter (108), the output end of the second micro-ring filter (108) is connected to the input end of an adjustable Sagnac reflector (109), and the output port (110) of the adjustable Sagnac reflector (109) is a laser output port.

2. The silicon-based widely tunable external cavity laser according to claim 1, characterized in that: The first reflective semiconductor optical amplifier (101) and the second reflective semiconductor optical amplifier both have one end with a high reflectivity end and the other end with a low reflectivity end, and the low reflectivity end is the output end of the first reflective semiconductor optical amplifier (101) and the second reflective semiconductor optical amplifier.

3. The silicon-based widely tunable external cavity laser according to claim 2, characterized in that: The first light spot size converter (103) and the second light spot size converter (104) both adopt a structure including an inverted cone coupler or a suspended waveguide coupler.

4. The silicon-based widely tunable external cavity laser according to claim 3, characterized in that: The optical switch (105) is composed of an equal-arm Mach-Zehnder interferometer.

5. The silicon-based widely tunable external cavity laser according to claim 4, characterized in that: The phase shifter (106) is a thermo-optical phase shifter.

6. The silicon-based widely tunable external cavity laser according to claim 5, characterized in that: The first micro-ring filter (107) and the second micro-ring filter (108) have different radii.

7. The silicon-based widely tunable external cavity laser according to claim 6, characterized in that: The first micro-ring filter (107) and the second micro-ring filter (108) are both narrow passband filters.

8. The silicon-based widely tunable external cavity laser according to claim 7, characterized in that: The adjustable Sagnac reflector (109) is composed of a Mach-Zehnder interferometer and a U-shaped waveguide, a thermo-optical phase shifter is integrated on one arm of the Mach-Zehnder interferometer, and the coupling ratios of the input and output couplers are both 50:

50.

9. The silicon-based widely tunable external cavity laser according to claim 1 or 8, characterized in that: The first spot size converter (103), the second spot size converter (104), the optical switch (105), the phase shifter (106), the first micro-ring filter (107), the second micro-ring filter (108) and the adjustable Sagnac reflector (109) can all be implemented by silicon waveguides.

10. The silicon-based widely tunable external cavity laser according to claim 9, characterized in that: The first reflective semiconductor optical amplifier (101), the second reflective semiconductor optical amplifier (102) and the silicon chip are aligned by a method including butt coupling, flip-chip or bonding.

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