CN-122000786-A - Hybrid integrated semiconductor laser and bandwidth boosting method

Abstract

The invention provides a hybrid integrated semiconductor laser and a bandwidth improving method, and relates to the field of optoelectronic devices. The hybrid integrated semiconductor laser comprises a semiconductor laser chip and a silicon nitride external cavity chip, wherein an optical feedback regulation structure is integrated in the silicon nitride external cavity chip to realize active control of feedback light, so that photon-photon resonance and detuning loading effects are introduced, and the modulation bandwidth of the direct-tuning laser is cooperatively improved. The hybrid integrated semiconductor laser provided by the invention has the advantages of simple structure, high preparation yield, capability of carrying out secondary promotion of bandwidth on a finished laser, flexible regulation and control, easiness in integration and wide applicability.

Inventors

• Na Quanxin
• ZHANG NAN
• LIU ZIMING
• ZHUANG DONGWEI
• Xie Qijie
• WANG LI
• WU MENGQI
• WANG LEI

Assignees

• 鹏城实验室

Dates

Publication Date

20260508

Application Date

20260123

Claims (9)

1. 1. The hybrid integrated semiconductor laser is characterized by comprising a semiconductor laser chip and a silicon nitride external cavity chip, wherein an optical feedback regulation structure is integrated on the silicon nitride external cavity chip, the optical feedback regulation structure is used for regulating the intensity and the phase of an optical signal from the silicon nitride external cavity chip to the semiconductor laser chip, the optical feedback is weak feedback, and the weak feedback duty ratio is less than or equal to 10 percent so as to introduce a photon-photon resonance effect and a detuning loading effect into the semiconductor laser chip to improve the modulation bandwidth of the semiconductor laser chip.
2. 2. The hybrid integrated semiconductor laser of claim 1, wherein the optical feedback modulation structure comprises a first tapered waveguide, a straight waveguide, a phase shift heater, a multimode interferometer, a micro-ring and a micro-ring heater, wherein the phase shift heater is integrated on the straight waveguide and is used for modulating the feedback optical phase, and the micro-ring heater is arranged on the micro-ring and is used for modulating the resonance wavelength of the micro-ring.
3. 3. The hybrid integrated semiconductor laser of claim 2, wherein the multimode interference coupler is configured to split an optical signal incident on the silicon nitride chip into two paths for coupling into waveguides on upper and lower sides of the micro-ring, respectively, and the coupling strength between the micro-ring and the waveguides on both sides is uniform.
4. 4. The hybrid integrated semiconductor laser of claim 2, wherein the perimeter of the micro-ring is set in the range of 1-5mm to match the resonant frequency of the micro-ring to the target photon-photon resonant frequency.
5. 5. The hybrid integrated semiconductor laser of claim 1, wherein the optical feedback conditioning structure comprises a first tapered waveguide, a straight waveguide, a phase shift heater, a directional coupler, a mach-zehnder interferometer, a sagnac loop, and a mach-zehnder interferometer heater integrated on one arm of the mach-zehnder interferometer for controlling feedback light intensity by interference effects.
6. 6. The hybrid integrated semiconductor laser of claim 2 or 5, wherein the semiconductor laser chip is coupled to the silicon nitride external cavity chip by the first tapered waveguide structure, and wherein the light exiting end surface of the semiconductor laser chip is cut with an 8 ° tilt angle to reduce reflection.
7. 7. The hybrid integrated semiconductor laser of claim 1, wherein the semiconductor laser chip is a direct modulation laser chip comprising at least a DFB laser, a DBR laser, and the operating band of the direct modulation laser chip covers at least either the C-band or the O-band.
8. 8. A bandwidth boosting method based on the hybrid integrated semiconductor laser of any one of claims 1 to 7, comprising: The optical feedback regulation structure regulates and controls the phase and intensity of the optical signal fed back to the semiconductor laser chip, and the photon-photon resonance effect is excited to provide basic gain for bandwidth improvement; The detuning loading effect on the laser is realized by utilizing the reflectivity difference of the silicon nitride external cavity chip under different wavelengths in combination with the frequency chirp characteristic generated in the direct modulation process of the semiconductor laser chip; And the inherent bandwidth limitation of the semiconductor laser chip is relieved through the synergistic effect of the photon-photon resonance effect and the detuning loading effect so as to improve the modulation bandwidth of the semiconductor laser chip.
9. 9. The bandwidth boost method of claim 8, wherein the small signal-3 dB modulation bandwidth of the hybrid integrated semiconductor laser is higher than the inherent bandwidth of the semiconductor laser chip.

Description

Hybrid integrated semiconductor laser and bandwidth boosting method Technical Field The invention belongs to the technical field of optoelectronic devices, and particularly relates to a hybrid integrated semiconductor laser and a bandwidth improving method. Background With the explosive growth of cloud computing, internet of things, artificial intelligence and other services, network data capacity and transmission rate demands continue to rise, and 400G/800G Ethernet technology is becoming a mainstream scheme of next-generation data centers. In this context, directly modulating a semiconductor laser as an irreplaceable light source for a data center, and improving the modulation bandwidth and rate of the directly modulated laser becomes a key challenge. However, conventional direct-tuning lasers are limited by relaxation oscillation and chip parasitic parameters, and the bandwidth is often difficult to break through by 25GHz. Although the bandwidth is improved by introducing a detuning loading effect and a photon-photon resonance effect in the prior art, the schemes generally adopt a monolithically integrated composite cavity structure, have the problems of low yield, sensitivity to chip structural parameters and environmental changes and the like, and are not widely applied in the commercial field. At present, commercial direct-tuning lasers still mainly depend on a traditional bandwidth lifting mode, and because bandwidth is difficult to break through, the requirements of the market on communication speed are continuously improved, so that the stock backlog of low-bandwidth laser chips is serious. On the other hand, the hybrid integration technology can use the silicon nitride-based waveguide structure as an external cavity of a laser, and the technology has been applied to the fields of coherent optical communication of a narrow linewidth laser, frequency modulation continuous wave laser radar, large-range tuning of laser wavelength and the like. However, most researches still focus on realizing narrow linewidth and wavelength tuning by using a silicon nitride external cavity, only a few researches try to improve the bandwidth of a direct-tuning laser by using the external cavity, and the schemes are generally based on a complex mechanism of self-injection locking, so that the problem that the feedback light intensity is difficult to accurately regulate and control is precisely key to realizing photon-photon resonance effect. In summary, the prior art has the disadvantages of complex structure, low yield, inflexible feedback control, and the like. Therefore, a hybrid integrated solution with simple structure, flexible regulation and control, high yield and capability of effectively improving the bandwidth of the direct-tuning laser is needed. Disclosure of Invention In view of the above, the invention provides a hybrid integrated semiconductor laser and a bandwidth increasing method, which aim to flexibly introduce photon-photon resonance and detuning loading effects by utilizing an optical feedback regulation structure in a silicon nitride external cavity chip so as to achieve the increase of the bandwidth of a finished laser. The technical scheme of the invention is realized as follows: The embodiment of the invention provides a hybrid integrated semiconductor laser, which comprises a semiconductor laser chip and a silicon nitride external cavity chip, wherein an optical feedback regulation structure is integrated on the silicon nitride external cavity chip, the optical feedback regulation structure is used for regulating the intensity and the phase of an optical signal from the silicon nitride external cavity chip to the semiconductor laser chip, the optical feedback is weak feedback, and the weak feedback duty ratio is less than or equal to 10 percent so as to introduce a photon-photon resonance effect and a detuning loading effect into the semiconductor laser chip to improve the modulation bandwidth of the semiconductor laser. In an embodiment, the optical feedback regulation structure comprises a first conical waveguide, a straight waveguide, a phase shift heater, a multimode interferometer, a micro-ring and a micro-ring heater, wherein the phase shift heater is integrated on the straight waveguide and is used for regulating the phase of feedback light, and the micro-ring heater is arranged on the micro-ring and is used for regulating the resonance wavelength of the micro-ring. In one embodiment, the multimode interference coupler is used for dividing the optical signal incident to the silicon nitride chip into two paths so as to be respectively coupled into the waveguides on the upper side and the lower side of the micro-ring, and the coupling strength between the micro-ring and the waveguides on the two sides is consistent. In one embodiment, the perimeter of the micro-ring is set in the range of 1-5mm to match the resonant frequency of the micro-ring to the target photon-photon resonant frequenc