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arxiv: 2606.19768 · v1 · pith:NXMBDDNB · submitted 2026-06-18 · physics.optics

μ-MOPA Architecture for Photonic Integrated Solid State Laser

Yu Guo , Yubo Wang , Haoqi Zhao , Fengyan Yang , Guangcanlan Yang , Hao Xie , Hong X. Tang This is my paper

Reviewed by Pith T0 review T1 audit T2 compute T3 formal T4 kernel 2026-06-26 16:45 UTCgrok-4.3pith:NXMBDDNBrecord.jsonopen to challenge →

classification physics.optics
keywords Nd:YAGphotonic integrationMOPAsolid state lasermicroring resonatorwaveguide amplifierDPSS laser
0
0 comments X

The pith

A μ-MOPA architecture integrates an Nd:YAG seed laser and amplifier on one photonic chip to deliver over 12 dBm output power.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper shows how to bring solid-state Nd:YAG lasers onto photonic chips using a master-oscillator-power-amplifier setup. A double-resonant microring resonator seed achieves a very low threshold of 2.9 microwatts. Separate optimization of the waveguide amplifier yields up to 46.6 decibels of gain. When combined in one device, the system produces more than 12 decibels-milliwatts of continuous-wave light. This approach addresses the difficulties of pump efficiency and power scaling that have prevented chip-scale DPSS lasers until now.

Core claim

The first photonic-integrated Nd:YAG laser-amplifier system is demonstrated with a micro-chip based master-oscillator-power-amplifier (μ-MOPA) architecture. The seed laser with a double-resonant microring resonator reaches a threshold as low as 2.9 μW. The single-pass waveguide amplifier, when optimized separately, provides up to 46.6 dB small-signal gain. Combining the low-threshold seed with cascaded waveguide amplifiers, the integrated μ-MOPA delivers more than 12 dBm of amplified continuous-wave output power. These results establish Nd:YAG waveguide integration as a practical route to compact and high-performance solid-state light sources.

What carries the argument

The μ-MOPA architecture with a double-resonant microring resonator seed laser and cascaded single-pass waveguide amplifiers, which together enable low-threshold operation and high-gain amplification in an integrated Nd:YAG platform.

If this is right

  • The seed laser operates with a threshold of only 2.9 μW, minimizing required pump power.
  • The amplifier achieves 46.6 dB small-signal gain in a single pass.
  • The full system produces over 12 dBm continuous-wave output in a fully integrated form.
  • This integration provides a route to compact solid-state light sources for precision metrology, quantum optics, and coherent communications.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The same architecture could be tested with other rare-earth gain media to reach different operating wavelengths.
  • Adding modulators or frequency converters on the same chip would create more complete on-chip optical systems.
  • Direct comparison of the integrated device against a discrete seed plus discrete amplifier would quantify any hidden integration penalties.

Load-bearing premise

The reported performance is achieved in a single fully integrated device rather than from separately optimized components whose combination does not incur additional integration losses.

What would settle it

A measurement showing that the combined on-chip device produces substantially lower power than the product of the separate seed threshold and amplifier gain figures, due to coupling or fabrication losses, would challenge the integration claim.

Figures

Figures reproduced from arXiv: 2606.19768 by Fengyan Yang, Guangcanlan Yang, Haoqi Zhao, Hao Xie, Hong X. Tang, Yubo Wang, Yu Guo.

Figure 2
Figure 2. Figure 2: For the pump mode, we extracted an intrinsic Q-factor of 122,000, corresponding to [PITH_FULL_IMAGE:figures/full_fig_p008_2.png] view at source ↗
read the original abstract

Diode-pumped solid-state (DPSS) lasers play a central role in modern photonics owing to their exceptional efficiency and ability to extend spectral coverage beyond the reach of semiconductor diodes. These attributes have enabled breakthroughs in precision metrology, quantum optics, and coherent communications. However, bringing the proven advantages of DPSS gain media such as Nd:YAG onto an integrated photonic platform has remained difficult, largely due to inefficient pump utilization and limited power-scaling in chip-scale implementations. Here, we demonstrate the first photonic-integrated Nd:YAG laser-amplifier system that overcomes these challenges with a micro-chip based master-oscillator-power-amplifier (\mu-MOPA) architecture. The seed laser, employing a double-resonant microring resonator, could reach a threshold as low as 2.9 \mu W. The single-pass waveguide amplifier, when optimized separately, provides up to 46.6 dB small-signal gain. Combining the low-threshold seed with cascaded waveguide amplifiers, the integrated \mu-MOPA delivers more than 12 dBm of amplified continuous-wave output power. These results establish Nd:YAG waveguide integration as a practical route to compact and high-performance solid-state light sources.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

1 major / 1 minor

Summary. The manuscript presents a photonic-integrated Nd:YAG laser-amplifier system using a micro-chip based master-oscillator-power-amplifier (μ-MOPA) architecture. The seed laser, employing a double-resonant microring resonator, reaches a threshold as low as 2.9 μW. The single-pass waveguide amplifier, when optimized separately, provides up to 46.6 dB small-signal gain. Combining the low-threshold seed with cascaded waveguide amplifiers, the integrated μ-MOPA is claimed to deliver more than 12 dBm of amplified continuous-wave output power. This is positioned as the first such integrated Nd:YAG laser-amplifier system addressing pump utilization and power-scaling challenges on chip.

Significance. If the monolithic integration achieves the reported performance without substantial additional losses, this would represent a meaningful advance in bringing DPSS laser advantages (efficiency, spectral coverage) to photonic integrated circuits. It could enable compact sources for precision metrology, quantum optics, and coherent communications. The low seed threshold and high reported gain are notable if verified in a single integrated device rather than separate components.

major comments (1)
  1. [Abstract] Abstract: The 46.6 dB small-signal gain is explicitly from a 'separately optimized' waveguide amplifier, with the final >12 dBm power obtained by 'combining' the seed with cascaded amplifiers. The central claim requires that this performance is preserved in the monolithic μ-MOPA without extra losses from waveguide-to-microring coupling, mode mismatch, or fabrication variations. The manuscript must provide direct evidence (e.g., measured gain or output power for the fully integrated device) that the headline numbers are not from separately optimized components.
minor comments (1)
  1. The manuscript should include fabrication details, measurement methods, error bars, and device images or schematics to allow verification of the integrated performance.

Simulated Author's Rebuttal

1 responses · 0 unresolved

Thank you for the detailed review of our manuscript on the photonic-integrated Nd:YAG μ-MOPA. We address the major comment regarding the distinction between separately optimized components and the integrated device performance below.

read point-by-point responses

  1. Referee: [Abstract] Abstract: The 46.6 dB small-signal gain is explicitly from a 'separately optimized' waveguide amplifier, with the final >12 dBm power obtained by 'combining' the seed with cascaded amplifiers. The central claim requires that this performance is preserved in the monolithic μ-MOPA without extra losses from waveguide-to-microring coupling, mode mismatch, or fabrication variations. The manuscript must provide direct evidence (e.g., measured gain or output power for the fully integrated device) that the headline numbers are not from separately optimized components.

    Authors: We thank the referee for highlighting this important point. The 46.6 dB small-signal gain is indeed reported from a separately optimized single-pass waveguide amplifier to demonstrate the capability of the Nd:YAG waveguide platform. However, the >12 dBm amplified output power is measured directly from the fully integrated μ-MOPA, where the low-threshold seed laser is monolithically combined with cascaded waveguide amplifiers on the same chip. The manuscript's results section presents experimental data for this integrated configuration, confirming that the system achieves the reported power levels. While integration introduces some additional considerations such as coupling losses, these are accounted for in the measured output, and the performance is preserved sufficiently to exceed 12 dBm. If the referee suggests, we can add a dedicated subsection or figure caption to explicitly contrast the separate and integrated measurements. revision: partial

Circularity Check

0 steps flagged

No circularity: experimental demonstration with no derivation chain

full rationale

This paper reports fabrication and measurement of an integrated Nd:YAG μ-MOPA device. The abstract and description contain no mathematical derivations, parameter fittings, uniqueness theorems, or self-citations used as load-bearing premises. Performance figures (threshold, gain, output power) are presented as measured results from the fabricated system, not as outputs of any equation that reduces to its own inputs. The distinction between separately optimized amplifier gain and the integrated result is stated explicitly without circular reduction. No steps meet the criteria for circularity.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

Experimental demonstration paper. No free parameters, mathematical axioms, or invented entities are introduced in the abstract. Claims rest on the unverified assumption that fabricated devices match the reported metrics.

pith-pipeline@v0.9.1-grok · 5758 in / 1036 out tokens · 33779 ms · 2026-06-26T16:45:43.813178+00:00 · methodology

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Reference graph

Works this paper leans on

69 extracted references · 1 canonical work pages · 1 internal anchor

  1. [1]

    The SiN photonic circuit patterns and bonding regions are defined by electron-beam lithography using FOx-16 (Dow-Corning) as the etching mask

    Device fabrication. The SiN photonic circuit patterns and bonding regions are defined by electron-beam lithography using FOx-16 (Dow-Corning) as the etching mask. The Si 3N4 layer is then etched with a fluorine-based inductively coupled plasma reactive ion etching process [48], followed by mask removal using buffered oxide etch. To ensure high surface qua...

  2. [2]

    On-chip Nd:YAG amplifier characterization is performed using the setup shown in Extended Data Fig

    Characterization of the waveguide amplifier. On-chip Nd:YAG amplifier characterization is performed using the setup shown in Extended Data Fig. 1a. The 808-nm pump is provided by a commercial Ti:sapphire laser (SolsTiS, M Squared), while a laser diode (Aerodiode, 1064LD-2-0-0) centered at 1.064µm serves as the signal source. The pump and signal are combin...

  3. [3]

    Laser characterization is conducted using the setup shown in Extended Data Fig

    Integrated microring lasers measurement. Laser characterization is conducted using the setup shown in Extended Data Fig. 2a, employing the same pump light sources as used for the waveguide amplifier measurements. 13 A fiber-based variable optical attenuator (VOA) is placed before coupling light into the chip, enabling linear control of the pump power for ...

  4. [4]

    Fan, T. Y. & Byer, R. L. Diode laser-pumped solid-state lasers.IEEE J. Quantum Electron. 24, 895–912 (2002)

    2002

  5. [5]

    Byer, R. L. Diode laser—pumped solid-state lasers.Science239, 742–747 (1988)

    1988

  6. [6]

    1 (springer, 2013)

    Koechner, W.Solid-state laser engineering, vol. 1 (springer, 2013)

    2013

  7. [7]

    Express25, 20437–20453 (2017)

    Hakobyan, S.et al.Full stabilization and characterization of an optical frequency comb from a diode-pumped solid-state laser with ghz repetition rate.Opt. Express25, 20437–20453 (2017)

    2017

  8. [8]

    J., Hakobyan, S., Schilt, S

    G¨ urel, K., Wittwer, V. J., Hakobyan, S., Schilt, S. & S¨ udmeyer, T. Carrier envelope offset frequency detection and stabilization of a diode-pumped mode-locked Ti:sapphire laser.Opt. Lett.42, 1035–1038 (2017)

    2017

  9. [9]

    S., Phillips, C

    Mayer, A. S., Phillips, C. R. & Keller, U. Watt-level 10-gigahertz solid-state laser enabled by self-defocusing nonlinearities in an aperiodically poled crystal.Nat. Commun.8, 1673 (2017)

    2017

  10. [10]

    Commun.13, 2584 (2022)

    Fritsch, K.et al.Dual-comb thin-disk oscillator.Nat. Commun.13, 2584 (2022)

    2022

  11. [11]

    R.et al.Coherently averaged dual-comb spectroscopy with a low-noise and high- power free-running gigahertz dual-comb laser.Opt

    Phillips, C. R.et al.Coherently averaged dual-comb spectroscopy with a low-noise and high- power free-running gigahertz dual-comb laser.Opt. Express31, 7103–7119 (2023)

    2023

  12. [12]

    & Gloria, A

    De Santis, R., Russo, T. & Gloria, A. An analysis on the potential of diode-pumped solid-state lasers for dental materials.Mater. Sci. Eng. C.92, 862–867 (2018)

    2018

  13. [13]

    Liu, B.et al.Principles and clinical applications of transcutaneous laser-assisted drug delivery: A narrative review.Scars, Burns & Healing10(2024)

    2024

  14. [14]

    Liu, H.et al.Review of laser-diode pumped Ti: sapphire laser.Microw. Opt. Technol. Lett. 63, 2135–2144 (2021)

    2021

  15. [15]

    & Van Uitert, L

    Geusic, J., Marcos, H. & Van Uitert, L. Laser oscillations in Nd-doped yttrium aluminum, yttrium gallium and gadolinium garnets.Appl. Phys. Lett.4, 182–184 (1964)

    1964

  16. [16]

    C., Seamans, J

    Tidwell, S. C., Seamans, J. F., Hamilton, C. E., Muller, C. H. & Lowenthal, D. D. Efficient, 15-W output power, diode-end-pumped Nd:YAG laser.Opt. Lett.16, 584–586 (1991)

    1991

  17. [17]

    Express13, 8725–8729 (2005)

    Qi, Y.et al.Nd:YAG ceramic laser obtained high slope-efficiency of 62% in high power applications.Opt. Express13, 8725–8729 (2005)

    2005

  18. [18]

    Lett.31, 405–408 (2019)

    Zhang, L.et al.A near 60% efficiency single-slab Nd:YAG high-power laser with adjustable pulse duration.IEEE Photonics Technol. Lett.31, 405–408 (2019)

    2019

  19. [19]

    & Petermann, K

    Huber, G., Kr¨ ankel, C. & Petermann, K. Solid-state lasers: status and future.J. Opt. Soc. 16 Am. B27, B93–B105 (2010)

    2010

  20. [22]

    Lett.46, 2127–2130 (2021)

    Yin, D.et al.Electro-optically tunable microring laser monolithically integrated on lithium niobate on insulator.Opt. Lett.46, 2127–2130 (2021)

    2021

  21. [23]

    Photon.18, 829–835 (2024)

    Liu, Y.et al.A fully hybrid integrated erbium-based laser.Nat. Photon.18, 829–835 (2024)

    2024

  22. [24]

    Lett.47, 1427–1430 (2022)

    Luo, Q.et al.Integrated ytterbium-doped lithium niobate microring lasers.Opt. Lett.47, 1427–1430 (2022)

    2022

  23. [25]

    Appl.14, 18 (2025)

    Singh, N.et al.Sub-2W tunable laser based on silicon photonics power amplifier.Light Sci. Appl.14, 18 (2025)

    2025

  24. [26]

    Photon.18, 1010–1023 (2024)

    Lu, X.et al.Emerging integrated laser technologies in the visible and short near-infrared regimes.Nat. Photon.18, 1010–1023 (2024)

    2024

  25. [27]

    & Tang, H

    Wang, Y., Guo, Y., Holguin-Lerma, J., Vezzoli, M. & Tang, H. X. Wafer-scale fabrication of a titanium-sapphire laser substrate by thermal diffusion.ACS Photonics11, 3303–3308 (2024)

    2024

  26. [28]

    Liu, Y.et al.A photonic integrated circuit–based erbium-doped amplifier.Science376, 1309–1313 (2022)

    2022

  27. [29]

    Bradley, J. D. & Pollnau, M. Erbium-doped integrated waveguide amplifiers and lasers.Laser Photonics Rev.5, 368–403 (2011)

    2011

  28. [30]

    Photon.1–7 (2025)

    Veisz, L.et al.Waveform-controlled field synthesis of sub-two-cycle pulses at the 100 TW peak power level.Nat. Photon.1–7 (2025)

    2025

  29. [31]

    Lett.43, 1562–1565 (2018)

    Deng, W.et al.High-efficiency 1064 nm nonplanar ring oscillator Nd:YAG laser with diode pumping at 885 nm.Opt. Lett.43, 1562–1565 (2018)

    2018

  30. [32]

    J.et al.Integrated multi-wavelength control of an ion qubit.Nature586, 538–542 (2020)

    Niffenegger, R. J.et al.Integrated multi-wavelength control of an ion qubit.Nature586, 538–542 (2020)

    2020

  31. [33]

    A.et al.Biological measurement beyond the quantum limit.Nat

    Taylor, M. A.et al.Biological measurement beyond the quantum limit.Nat. Photon.7, 229–233 (2013)

    2013

  32. [34]

    Menazea, A. A. & Abdelghany, A. Precipitation of silver nanoparticle within silicate glassy matrix via Nd:YAG laser for biomedical applications.Radiat. Phys. Chem.174, 108958 (2020)

    2020

  33. [35]

    Med.55, 257–267 (2023)

    Kranz, S.et al.Optical coherence tomography-guided Nd:YAG laser treatment and follow-up 17 of basal cell carcinoma.Lasers Surg. Med.55, 257–267 (2023)

    2023

  34. [36]

    Med.(2025)

    Shi, J.et al.Therapeutic effects of Q-switched 1064 nm Nd:YAG laser on rosacea in a mouse model: Inflammation and angiogenesis modulation.Lasers Surg. Med.(2025)

    2025

  35. [37]

    D., Dhanashekar, M

    Gurusami, K., Chandramohan, D., Kumar, S. D., Dhanashekar, M. & Sathish, T. Strengthening mechanism of Nd: YAG laser shock peening for commercially pure titanium (CP-TI) on surface integrity and residual stresses.Mater. Today Proc.21, 981–987 (2020)

    2020

  36. [38]

    & Genna, S

    Leone, C. & Genna, S. Heat affected zone extension in pulsed Nd:YAG laser cutting of CFRP. Compos. B Eng.140, 174–182 (2018)

    2018

  37. [39]

    Lett.49, 1397–1400 (2024)

    Li, H.et al.Heterogeneous integration of an on-chip Nd:YAG whispering gallery mode laser with a lithium-niobate-on-insulator platform.Opt. Lett.49, 1397–1400 (2024)

    2024

  38. [40]

    & Chen, F

    Li, H., Wang, Z., Wang, L., Tan, Y. & Chen, F. Optically pumped milliwatt whispering-gallery microcavity laser.Light: Sci. Appl.12, 223 (2023)

    2023

  39. [41]

    Bogaerts, W.et al.Silicon microring resonators.Laser Photonics Rev.6, 47–73 (2012)

    2012

  40. [43]

    E.et al.Monolithically integrated erbium-doped polycrystalline Al 2O3 waveguide amplifier on silicon photonics platform.Opt

    Osornio-Martinez, C. E.et al.Monolithically integrated erbium-doped polycrystalline Al 2O3 waveguide amplifier on silicon photonics platform.Opt. Express33, 23491–23502 (2025)

    2025

  41. [44]

    Lett.47, 4786–4789 (2022)

    Liang, Y.et al.Ultra-low loss SiN edge coupler interfacing with a single-mode fiber.Opt. Lett.47, 4786–4789 (2022)

    2022

  42. [45]

    Brunetti, G., Heuvink, R., Schreuder, E., Armenise, M. N. & Ciminelli, C. Silicon nitride spot size converter with very low loss over the C-band.IEEE Photon. Technol. Lett.35, 1215–1218 (2023)

    2023

  43. [46]

    Bao, R.et al.An erbium-doped waveguide amplifier on thin film lithium niobate with an output power exceeding 100 mW.Laser Photonics Rev.19, 2400765 (2024)

    2024

  44. [47]

    Lett.50, 3624–3627 (2025)

    Wei, Z.et al.Erbium-doped lithium niobate waveguide amplifier enhanced by an inverse- designed on-chip reflector.Opt. Lett.50, 3624–3627 (2025)

    2025

  45. [48]

    Lett.48, 1810–1813 (2023)

    Zhang, Y.et al.On-chip ytterbium-doped lithium niobate waveguide amplifiers with high net internal gain.Opt. Lett.48, 1810–1813 (2023)

    2023

  46. [49]

    Lett.48, 4344–4347 (2023)

    Zhang, Z.et al.Erbium-ytterbium codoped thin-film lithium niobate integrated waveguide amplifier with a 27 dB internal net gain.Opt. Lett.48, 4344–4347 (2023)

    2023

  47. [50]

    Singh, N.et al.Watt-class silicon photonics-based optical high-power amplifier.Nat. Photon. 19, 307–314 (2025). 18

    2025

  48. [51]

    & Tang, H

    Wang, Y., Guo, Y., Zhou, Y., Xie, H. & Tang, H. X. Heterogeneous sapphire-supported low-loss photonic platform.Opt. Express32, 20146–20152 (2024)

    2024

  49. [53]

    C., Jacobs, S

    Brown, D. C., Jacobs, S. D. & Nee, N. Parasitic oscillations, absorption, stored energy density and heat density in active-mirror and disk amplifiers.Appl. Opt.17, 211–224 (1978)

    1978

  50. [54]

    Jia, D.et al.High-efficiency edge couplers enabled by vertically tapering on lithium-niobate photonic chips.Appl. Phys. Lett.123, 263502 (2023)

    2023

  51. [55]

    He, L.et al.Low-loss fiber-to-chip interface for lithium niobate photonic integrated circuits. Opt. Lett.44, 2314–2317 (2019)

    2019

  52. [56]

    Photon.19, 709–717 (2025)

    Siddharth, A.et al.Ultrafast tunable photonic-integrated extended-DBR pockels laser.Nat. Photon.19, 709–717 (2025)

    2025

  53. [57]

    & Garc´ ıa-Blanco, S

    Mu, J., Dijkstra, M., Korterik, J., Offerhaus, H. & Garc´ ıa-Blanco, S. M. High-gain waveguide amplifiers in Si 3N4 technology via double-layer monolithic integration.Photonics Res.8, 1634–1641 (2020)

    2020

  54. [58]

    & Pollnau, M

    Yang, J., van Dalfsen, K., W¨ orhoff, K., Ay, F. & Pollnau, M. High-gain Al2O3: Nd 3+ channel waveguide amplifiers at 880 nm, 1060 nm, and 1330 nm.Appl. Phys. B101, 119–127 (2010)

    2010

  55. [59]

    & Garc´ ıa-Blanco, S

    Jongebloed, B., Osornio-Martinez, C., Wang, K., Dijkstra, M. & Garc´ ıa-Blanco, S. Fiber-to- fiber gain in Nd-doped aluminium oxide waveguide amplifiers.Opt. Express34, 4522–4534 (2026)

    2026

  56. [60]

    W.et al.High-power red, orange, and green Pr 3+: LiYF 4 lasers.Opt

    Metz, P. W.et al.High-power red, orange, and green Pr 3+: LiYF 4 lasers.Opt. Lett.39, 3193–3196 (2014)

    2014

  57. [61]

    J., Payne, S

    Atherton, L. J., Payne, S. A. & Brandle, C. D. Oxide and fluoride laser crystals.Annu. Rev. Mater. Res.23, 453–502 (1993)

    1993

  58. [62]

    High-pulse-energy integrated mode-locked lasers based on a Mamyshev oscillator

    Qiu, Z.et al.High-pulse-energy integrated mode-locked lasers based on a Mamyshev oscillator. Preprint at https://arxiv.org/abs/2509.05133 (2025)

    work page internal anchor Pith review Pith/arXiv arXiv 2025

  59. [63]

    Guo, Q.et al.Ultrafast mode-locked laser in nanophotonic lithium niobate.Science382, 708–713 (2023). 19 a c 0 1 2 3 30 35 40 45 50 55 Conversion efficiency η (%) Signal input power (mW) Ppump = 13.4 mW Ppump = 8.4 mW Ppump = 4.4 mW FPC WDM 808/1064 nm WDM 808/1064 nm FPC Pump dump PM 808 nm CW pump 1064 nm signal OSA PM 1060 1062 1064 1066 1068 1070 −60 −...

    2023

  60. [64]

    A., Vezzoli, M., Guo, Y

    Wang, Y., Holgu´ ın-Lerma, J. A., Vezzoli, M., Guo, Y. & Tang, H. X. Photonic-circuit- integrated titanium: sapphire laser.Nat. Photon.17, 338–345 (2023)

    2023

  61. [65]

    Liu, J.-M.Photonic Devices(Cambridge University Press, 2005)

    2005

  62. [66]

    & Shiao, H.-P

    Wang, C.-Y., Shih, H.-H., Wang, S.-C., Tu, Y.-K. & Shiao, H.-P. Novel 0.98/1.55µm dichroic coupler based on lithium niobate.Fiber Integr. Opt.11, 375–383 (1992)

    1992

  63. [67]

    Rep.13, 22720 (2023)

    Thottoli, A.et al.Highly efficient and selective integrated directional couplers for multigas sensing applications.Sci. Rep.13, 22720 (2023)

    2023

  64. [68]

    & Chen, Y.-F

    Cho, C., Tuan, P., Yu, Y., Huang, K.-F. & Chen, Y.-F. A cryogenically cooled Nd:YAG monolithic laser for efficient dual-wavelength operation at 1061 and 1064 nm.Laser Phys. Lett.10, 045806 (2013)

    2013

  65. [69]

    M., Olsson, A

    Becker, P. M., Olsson, A. A. & Simpson, J. R.Erbium-doped fiber amplifiers: fundamentals and technology(Elsevier, 1999)

    1999

  66. [70]

    Yang, J.et al.Titanium: sapphire-on-insulator integrated lasers and amplifiers.Nature630, 853–859 (2024)

    2024

  67. [71]

    Devor, D. P. & DeShazer, L. G. Evidence of Nd:YAG quantum efficiency dependence on nonequivalent crystal field effects.Opt. Commun.46, 97–102 (1983)

    1983

  68. [72]

    & O’Sullivan, M.Fiber Optic Measurement Techniques(Academic Press, 2009)

    Hui, R. & O’Sullivan, M.Fiber Optic Measurement Techniques(Academic Press, 2009)

    2009

  69. [73]

    The use of fast fourier transform for the estimation of power spectra: A method based on time averaging over short, modified periodograms.IEEE Trans

    Welch, P. The use of fast fourier transform for the estimation of power spectra: A method based on time averaging over short, modified periodograms.IEEE Trans. Audio Electroacoust. 15, 70–73 (1967). 14

    1967