Ultra-narrow laser spectral width measurement and calibration instrument
By designing an ultra-narrow laser spectral width measurement and calibration instrument, and utilizing the optical path composed of optical devices and spectral difference calculation, the problem of the laser spectrum measurement method being affected by the environment was solved, and the accurate calibration and stability of the laser spectrum were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NORTH CHINA UNIVERSITY OF TECHNOLOGY
- Filing Date
- 2023-04-14
- Publication Date
- 2026-06-02
AI Technical Summary
The accuracy of existing laser spectrum measurement methods for ultra-narrow lasers is affected by factors such as ambient temperature, vibration, and frequency instability, resulting in inaccurate calibration.
An ultra-narrow laser spectral width measurement and calibration instrument was designed. It utilizes an optical path composed of optical devices such as a 3dB optical coupler, an erbium-doped fiber amplifier, and a polarization controller, combined with an adjustable Faraday polarization mirror and a spectral analyzer, to measure the full width at half maximum (FWHM) of the ultra-narrow laser by calculating the spectral difference, thereby achieving accurate calibration.
It improves the accuracy and stability of ultra-narrow laser spectrum measurements and enables rapid and accurate correction of laser spectrum jitter.
Smart Images
Figure CN116593000B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the fields of laser communication and optoelectronic technology, and in particular to an ultra-narrow laser spectral width measurement and calibration instrument. Background Technology
[0002] With the rapid development of internet applications, the demand for high-speed, broadband communication is becoming increasingly urgent. Ultra-dense wavelength division multiplexing (UWDM) optical communication technology is an important means to further improve system transmission capacity. The construction of UWDM optical communication systems relies on various high-performance optoelectronic devices, among which ultra-narrow linewidth lasers are key components for reducing channel spacing and increasing the number of multiplexed channels. However, due to the very narrow spectral linewidth of ultra-narrow linewidth lasers, traditional laser spectral linewidth measurement methods based on phase discrimination, frequency discrimination, and coherence are easily affected by environmental temperature, vibration, frequency instability, and coherence degradation, resulting in reduced accuracy in ultra-narrow laser spectral width measurements and making it impossible to quickly and accurately correct laser spectral jitter. Summary of the Invention
[0003] The technical problem to be solved by this invention is to overcome the shortcomings of existing laser spectrum measurement methods and to propose an ultra-narrow laser spectral width measurement and calibration instrument.
[0004] The technical solution of the present invention:
[0005] An ultra-narrow laser spectral width measurement and calibration instrument includes: an ultra-narrow laser source under test, a 3dB optical coupler, an erbium-doped fiber amplifier, a polarization controller, a polarization beam splitter, first to fourth optical circulators, a first fiber grating reflector, a second fiber grating reflector, a first polarization-maintaining fiber, a second polarization-maintaining fiber, a first optical isolator, a second optical isolator, a 1:9 optical coupler, a first adjustable Faraday polarization mirror, a second adjustable Faraday polarization mirror, a 3×3 optical coupler, a spectrum analyzer, and a digital signal processor.
[0006] The connections of the various devices are as follows:
[0007] The output port of the ultra-narrow laser source under test is connected to the first port of a 3dB optical coupler. The second port of the 3dB optical coupler is connected to the third port of a 3×3 optical coupler. The third port of the 3dB optical coupler is connected to the input port of an erbium-doped fiber amplifier. The output port of the erbium-doped fiber amplifier is connected to the input port of a polarization beam splitter via a polarization controller. The fast-axis output port of the polarization beam splitter is connected to the first port of a first optical circulator. The second port of the first optical circulator is connected to one end of a first fiber grating reflector. The other end of the first fiber grating reflector is connected to the third port of a second optical circulator. The third port of the first optical circulator is connected to the first port of the second optical circulator. The second port of the second optical circulator is connected to one end of a first polarization-maintaining fiber. The other end of the first polarization-maintaining fiber is connected to the input port of a first optical isolator. The output port of the first optical isolator is connected to the output port of a 1:9 optical coupler. The input port of the 1:9 optical coupler is connected to the fourth port of the 3×3 optical coupler. The 90% output port of the 1:9 optical coupler is connected to the first port of the third optical circulator. The second port of the third optical circulator is connected to one end of the second fiber grating reflector. The other end of the second fiber grating reflector is connected to the third port of the fourth optical circulator. The third port of the third optical circulator is connected to the first port of the fourth optical circulator. The second port of the fourth optical circulator is connected to one end of the second polarization-maintaining fiber. The other end of the second polarization-maintaining fiber is connected to the input port of the second optical isolator. The output port of the second optical isolator is connected to the fifth port of the 3×3 optical coupler. The first and second ports of the 3×3 optical coupler are connected to the first and second adjustable Faraday polarization mirrors, respectively. The sixth port of the 3×3 optical coupler is connected to the input port of the spectrometer. The output port of the spectrometer is connected to the digital signal processor.
[0008] The length ratio of the second polarization-maintaining fiber to the first polarization-maintaining fiber should be greater than 10:1.
[0009] The reflectivity adjustment range of the first and second adjustable Faraday polarization mirrors is 0% to 100%. When the reflectivity of the first adjustable Faraday polarization mirror is adjusted to 100% and the emissivity of the second adjustable Faraday polarization mirror is adjusted to 0%, the spectral distribution measured by the spectrometer is denoted as S1(λ). When the reflectivity of the first adjustable Faraday polarization mirror is adjusted to 0% and the emissivity of the second adjustable Faraday polarization mirror is adjusted to 100%, the spectral distribution measured by the spectrometer is denoted as S2(λ). Using a digital signal processor, the difference between S1(λ) and S2(λ) is calculated and denoted as: S(λ) = S1(λ) - S2(λ), thereby allowing the measurement of the full width at half maximum (FWHM) of the ultra-narrow laser spectrum.
[0010] The reflection spectrum range of the first fiber grating reflector and the second fiber grating reflector should include the output wavelength of the ultra-narrow laser source under test. By adjusting the reflectivity of the first fiber grating reflector and the second fiber grating reflector, fine-tuning correction of the ultra-narrow laser spectral width can be achieved. Attached Figure Description
[0011] Figure 1 Ultra-narrow laser spectral width measurement and calibration instrument. Implementation
[0012] The present invention will now be further described with reference to the accompanying drawings.
[0013] like Figure 1 An ultra-narrow laser spectral width measurement and calibration instrument includes: an ultra-narrow laser source under test 1, a 3dB optical coupler 12, an erbium-doped fiber amplifier 2, a polarization controller 3, a polarization beam splitter 4, first to fourth optical circulators 31, 32, 33, and 34, a first fiber grating reflector 51, a second fiber grating reflector 52, a first polarization-maintaining fiber 61, a second polarization-maintaining fiber 62, a first optical isolator 71, a second optical isolator 72, a 1:9 optical coupler 6, a first adjustable Faraday polarization mirror 81, a second adjustable Faraday polarization mirror 82, a 3×3 optical coupler 7, a spectrum analyzer 9, and a digital signal processor 10.
[0014] The connections of the various devices are as follows:
[0015] The output port of the ultra-narrow laser source 1 under test is connected to the first port of a 3dB optical coupler 12. The second port of the 3dB optical coupler 12 is connected to the third port of a 3×3 optical coupler 7. The third port of the 3dB optical coupler 12 is connected to the input port of an erbium-doped fiber amplifier 2. The output port of the erbium-doped fiber amplifier 2 is connected to the input port of a polarization beam splitter 4 via a polarization controller 3. The fast-axis output port of the polarization beam splitter 4 is connected to the first port of a first optical circulator 31. The second port of the first optical circulator 31 is connected to one end of a first fiber grating reflector 51. The other end of the first fiber grating reflector 51 is connected to the third port of a second optical circulator 32. The third port of the first optical circulator 31 is connected to the first port of the second optical circulator 32. The second port of the second optical circulator 32 is connected to one end of a first polarization-maintaining fiber 61. The other end of the first polarization-maintaining fiber 61 is connected to the input port of a first optical isolator 71. The output port of the first optical isolator 71 is connected to the output port of a 1:9 optical coupler 6. The 10% output port of the 1:9 optical coupler 6 is connected to the fourth port of the 3×3 optical coupler 7. The 90% output port of the 1:9 optical coupler 6 is connected to the first port of the third optical circulator 33. The second port of the third optical circulator 33 is connected to one end of the second fiber grating reflector 52. The other end of the second fiber grating reflector 52 is connected to the third port of the fourth optical circulator 34. The third port of the third optical circulator 33 is connected to the first port of the fourth optical circulator 34. The second port of the fourth optical circulator 34 is connected to one end of the second polarization-maintaining fiber 62. The other end of the second polarization-maintaining fiber 62 is connected to the input port of the second optical isolator 72. The output port of the second optical isolator 72 is connected to the fifth port of the 3×3 optical coupler 7. The first and second ports of the 3×3 optical coupler 7 are connected to the first and second Faraday polarization mirrors 81 and 82, respectively. The sixth port of the 3×3 optical coupler 7 is connected to the input port of the spectrometer 9. The output port of the spectrometer 9 is connected to the digital signal processor 10.
[0016] The length ratio of the second polarization-maintaining fiber 62 to the first polarization-maintaining fiber 61 should be greater than 10:1.
[0017] The reflectivity adjustment range of the first and second Faraday polarization mirrors 81 and 82 is 0% to 100%. When the reflectivity of the first Faraday polarization mirror 81 is adjusted to 100% and the reflectivity of the second Faraday polarization mirror 82 is adjusted to 0%, the spectral distribution measured by the spectrometer is denoted as S1(λ). When the reflectivity of the first Faraday polarization mirror 81 is adjusted to 0% and the emissivity of the second Faraday polarization mirror 82 is adjusted to 100%, the spectral distribution measured by the spectrometer is denoted as S2(λ). The difference between S1(λ) and S2(λ) is calculated using the digital signal processor 10 and denoted as: S(λ) = S1(λ) - S2(λ), thereby allowing the measurement of the full width at half maximum (FWHM) of the ultra-narrow laser spectrum.
[0018] The reflection spectrum range of the first fiber grating reflector 51 and the second fiber grating reflector 52 should include the output wavelength of the ultra-narrow laser source under test. By adjusting the reflectivity of the first fiber grating reflector 51 and the second fiber grating reflector 52, the fine-tuning correction of the ultra-narrow laser spectrum can be achieved.
Claims
1. A measurement and calibration instrument for ultra-narrow laser spectral width, characterized in that, The ultra-narrow laser spectral width measurement and calibration instrument includes: an ultra-narrow laser source under test (1), a 3dB optical coupler (12), an erbium-doped fiber amplifier (2), a polarization controller (3), a polarization beam splitter (4), first to fourth optical circulators (31), (32), (33), (34), a first fiber grating reflector (51), a second fiber grating reflector (52), a first polarization-maintaining fiber (61), a second polarization-maintaining fiber (62), a first optical isolator (71), a second optical isolator (72), a 1:9 optical coupler (6), a first adjustable Faraday polarization mirror (81), a second adjustable Faraday polarization mirror (82), a 3×3 optical coupler (7), a spectrum analyzer (9), and a digital signal processor (10). The connections of the components constituting this ultra-narrow laser spectral width measurement and calibration instrument are as follows: The output port of the ultra-narrow laser source under test (1) is connected to the first port of the 3dB optical coupler (12), the second port of the 3dB optical coupler (12) is connected to the third port of the 3×3 optical coupler (7), the third port of the 3dB optical coupler (12) is connected to the input port of the erbium-doped fiber amplifier (2), the output port of the erbium-doped fiber amplifier (2) is connected to the input port of the polarization beam splitter (4) via the polarization controller (3), the polarization fast axis output port of the polarization beam splitter (4) is connected to the first port of the first optical circulator (31), and the first optical circulator... The second port of the shaper (31) is connected to one end of the first fiber grating reflector (51), the other end of the first fiber grating reflector (51) is connected to the third port of the second optical circulator (32), the third port of the first optical circulator (31) is connected to the first port of the second optical circulator (32), the second port of the second optical circulator (32) is connected to one end of the first polarization-maintaining fiber (61), the other end of the first polarization-maintaining fiber (61) is connected to the input port of the first optical isolator (71), and the output port of the first optical isolator (71) is connected to the output port of the 1:9 optical coupler (6). The input port of the 1:9 optical coupler (6) is connected to the fourth port of the 3×3 optical coupler (7). The 90% output port of the 1:9 optical coupler (6) is connected to the first port of the third optical circulator (33). The second port of the third optical circulator (33) is connected to one end of the second fiber grating reflector (52). The other end of the second fiber grating reflector (52) is connected to the third port of the fourth optical circulator (34). The third port of the third optical circulator (33) is connected to the first port of the fourth optical circulator (34). The fourth optical circulator (34) The second port is connected to one end of the second polarization-maintaining fiber (62), the other end of the second polarization-maintaining fiber (62) is connected to the input port of the second optical isolator (72), the output port of the second optical isolator (72) is connected to the fifth port of the 3×3 optical coupler (7), the first and second ports of the 3×3 optical coupler (7) are connected to the first and second Faraday polarization mirrors (81) and (82) respectively, the sixth port of the 3×3 optical coupler (7) is connected to the input port of the spectrometer (9), and the output port of the spectrometer (9) is connected to the digital signal processor (10).
2. The ultra-narrow laser spectral width measurement and calibration instrument according to claim 1, characterized in that: The length ratio of the second polarization-maintaining fiber (62) to the first polarization-maintaining fiber (61) should be greater than 10:
1.
3. The ultra-narrow laser spectral width measurement and calibration instrument according to claim 1, characterized in that: The reflectivity adjustment range of the first and second Faraday polarization mirrors (81) and (82) is 0% to 100%. When the reflectivity of the first Faraday polarization mirror (81) is adjusted to 100% and the emissivity of the second Faraday polarization mirror (82) is adjusted to 0%, the spectral distribution measured by the spectrometer is denoted as S1(λ). When the reflectivity of the first Faraday polarization mirror (81) is adjusted to 0% and the reflectivity of the second Faraday polarization mirror (82) is adjusted to 100%, the spectral distribution measured by the spectrometer is denoted as S2(λ). The difference between S1(λ) and S2(λ) is calculated using the digital signal processor (10) and denoted as: S(λ) = S1(λ) - S2(λ), so that the full width at half maximum (FWHM) of the ultra-narrow laser spectrum can be measured.
4. The ultra-narrow laser spectral width measurement and calibration instrument according to claim 1, characterized in that: The reflection spectrum range of the first fiber grating reflector (51) and the second fiber grating reflector (52) should include the output wavelength of the ultra-narrow laser source (1) under test. Adjusting the reflectivity of the first fiber grating reflector (51) and the second fiber grating reflector (52) can achieve fine-tuning correction of the ultra-narrow laser spectrum.