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i l St. Petersburg Polytechnic University Journal. Physics and Mathematics. 2022 Vol. 15, No. 3.3 Научно-технические ведомости СПбГПУ. Физико-математические науки. 15 (3.3) 2022
EXPERIMENTAL TECHNIQUE AND DEVICES
Conference materials UDC 538.9
DOI: https://doi.org/10.18721/JPM.153.373
Integrated optical transceiver based on III-V microdisk laser and photodiode
N. V. Kryzhanovskaya 1 2H, E. I. Moiseev 1 2, A. S. Dragunova 1 2, M. V. Maximov 2, S. A. Mintairov 3, N. A. Kaluzhnyy 3, F. I. Zubov 2, M. M. Kulagina 3, J. A. Guseva 3, A. I. Likhachev 3, A. E. Zhukov 1
1 National Research University Higher School of Economics, St Petersburg, Russia;
2 Alferov University, St. Petersburg, Russia;
3 Ioffe Institute, St. Petersburg, Russia H nkryzhanovskaya@hse.ru
Abstract. In this work, we study III-V p-i-n photodetectors and disk microlasers in terms of their static and small-signal modulation frequency response. InGaAs/GaAs quantum well-dots (QWDs) are used as the active region of the devices to provide operation wavelength around 1.1 ^m, high optical and frequency response and temperature stability of characteristics. 30 |^m-in-diameter microdisk lasers revealed CW output power level of 15—22 mW and error-free 10 Gbit/s data transmission at 30 eC without temperature stabilization. The microdisk laser and the p-i-n photodiode were heterogeneously integrated on a silicon substrate by Au-Au thermocompression bonding to form a compact transceiver. Detection of microlaser emission by the closely placed p-i-n photodiode is studied. The absolute value of the responsivity of the waveguide detector as high as 0.68 A/W for the unbiased device is demonstrated. The efficiency of the optical link at the level of 1.4% is achieved. Approaches to obtain higher efficiency of the optical link are discussed.
Keywords: microdisk laser, waveguide detector, transceiver, quantum well-dots
Funding: The fabrication of the microlaser and photodiode is supported by the Russian Science Foundation grant 18-12-00287, https://rscf.ru/project/18-12-00287/. The study of the laser's output power was implemented in the framework of the Basic Research Program at the National Research University Higher School of Economics (HSE University).
Citation: Kryzhanovskaya N. V., Moiseev E. I., Dragunova A. S., Maximov M. V., Mintairov S. A., Kaluzhnyy N. A., Zubov F. I., Kulagina M. M., Guseva J. A., Likhachev A. I., Zhukov A. E., Integrated optical transceiver based on III-V microdisk laser and photodiode. St. Petersburg State Polytechnical University Journal. Physics and Mathematics, 15 (3.3) (2022) 371-375. DOI: https://doi.org/10.18721/jPM.153.373
This is an open access article under the CC BY-NC 4.0 license (https://creativecommons. org/licenses/by-nc/4.0/)
Материалы конференции УДК 538.9
DOI: https://doi.org/10.18721/JPM.153.373
Интегральный оптический трансивер на базе Ш-У микродискового лазера и фотодиода
Н. В. Крыжановская 1 2Н, Э. И. Моисеев 1 2, А. С. Драгунова 1 2, М. В. Максимов 2, С. А. Минтаиров 3, Н. А. Калюжный 3, Ф.И. Зубов 2, М. М. Кулагина 3, Ю. А. Гусева 3, А. И. Лихачев 3, А. Е. Жуков 1
1 Национальный исследовательский университет «Высшая школа экономики», Санкт-Петербург, Россия; 2 Академический университет им. Ж. И. Алферова, Санкт-Петербург, Россия;
© Kryzhanovskaya N. V., Moiseev E. I., Dragunova A. S., Maximov M. V., Mintairov S. A., Kaluzhnyy N. A., Zubov F. I., Kulagina M. M., Guseva J. A., Likhachev A. I., Zhukov A. E., 2022. Published by Peter the Great St.Petersburg Polytechnic University.
3 Физико-технический институт им. А.Ф. Иоффе, Санкт-Петербург, Россия н nkryzhanovskaya@hse.ru
Аннотация. В данной работе мы исследуем p-i-n фотодетекторы III-V и дисковые микролазеры с точки зрения их статических характеристик и возможности малосигнальной частотной модуляции. Микродисковый лазер и p-i-n фотодиод были интегрированы на кремниевой подложке с помощью термокомпрессионного соединения Au-Au для формирования компактного приемопередатчика. Исследовано детектирование излучения микролазера с помощью близко расположенного p-i-n фотодиода.
Ключевые слова: микродисковый лазер, волноводный детектор, приемопередатчик, квантовые яма-точки
Финансирование: Изготовление микролазера и фотодиода выполнено при поддержке гранта РНФ 18-12-00287, https://rscf.ru/project/18-12-00287/. Исследование выходной мощности лазера выполнено в рамках Программы фундаментальных исследований НИУ ВШЭ.
Ссылка при цитировании: Крыжановская Н. В., Моисеев Э. И., Драгунова А. С., Максимов М. В., Минтаиров С. А., Калюжный Н. А., Зубов Ф. И., Кулагина М. М., Гусева Ю. А., Лихачев А. И., Жуков А. Е. Интегральный оптический трансивер на базе III-V микродискового лазера и фотодиода // Научно-технические ведомости СПбГПУ. Физико-математические науки. 2022. Т. 15. № 3.3. C. 371-375. DOI: https:// doi.org/10.18721/JPM.153.373
Статья открытого доступа, распространяемая по лицензии CC BY-NC 4.0 (https:// creativecommons.org/licenses/by-nc/4.0/)
Introduction
Semiconductor resonators with disk geometry supporting whispering gallery modes (WGMs) are a promising basis for creating energy-efficient and small-sized coherent light sources suitable for various applications [1]. For a number of practical applications, it is desirable to combine a semiconductor WGM microlaser with a photodetector to form a transceiver. For example, such transceivers with an open optical channel available for external action can be used as various types of microsensors (biosensor, nanoparticle detection), galvanic isolation, contactless control, etc [2]. Such an optical component that includes a laser source, a photodetector, and (optionally) an additional passive element (e.g., optical waveguide) should be fabricated on silicon-on-insulator substrates using complementary metal-oxide-semiconductor (CMOS) technologies for further signal processing. Formation of photonic waveguides and optical modulators integrated over CMOS circuits have been already demonstrated [3, 4]. III-V semiconductor lasers have been grown directly on silicon substrate [5], but rather high growth temperature (above 500 °C) is not compatible with CMOS processing. Direct bonding of III-V active devices on silicon platform offers an acceptable low temperature process that is compatible with CMOS fabrication. Moreover, III-V devices can be transferred onto pre-determined sites on the Si-based wafer without selective-area overgrowth. In this work, we report on the design, fabrication and characterization of an optical transceivers based on III-V microdisk lasers and photodetector bonded onto silicon substrate.
Materials and Methods
In this work, we use semiconductor microdisk (MD) laser as a light source for a compact transceiver. MD lasers demonstrate low energy-to-data ratio (1.5 pJ/bit for the 10-^m in diameter laser) and in the plane output emission, which facilitates the integration of such microlasers with other planar optoelectronic elements even in the far field. For light detection we used a waveguide p-i-n photodiode. Metal-organic vapor phase epitaxy was used to grow the epitaxial structures of the p-i-n photodiode and the laser on an n±GaAs substrate misoriented by 6° toward [111] direction. The active region of the photodiode consists of ten stacked InGaAs/GaAs quantum
© Крыжановская Н. В., Моисеев Э. И., Драгунова А. С., Максимов М. В., Минтаиров С. А., Калюжный Н. А., Зубов Ф. И., Кулагина М. М., Гусева Ю. А., Лихачев А. И., Жуков А. Е., 2022. Издатель: Санкт-Петербургский политехнический университет Петра Великого.
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Experimental technique and devices
well-dots structures, with a plane quantum dot density in excess of 1*10n cm-2. MD laser with a mesa diameter D of 30 ^m were formed by photolithography and dry etching (STE ICPe68). The photodiode was made in the form of a parallelepiped cleaved along {110} crystallographic planes. The length and the width of the photodiode were 200 ^m and 50 ^m, respectively. Top p-contact was formed using a 0.1 ^m thick AgMn/Ni/Au alloy. As an n-contact, we used the metallization of the AuGe and Ni alloy, deposited by thermal evaporation on the back side of the substrate. The light-absorbing edges of the photodiode structures were formed by cleaving crystals without applying additional anti-reflective coatings.
Fig. 1. Photo of the microlaser and photodiode bonded onto the Si substrate
Microlaser and photodiode were bonded onto Si substrate using Au-Au thermocompressive bonding (Fig. 1). The distance between the MD sidewall and the PD was as small as 25 ^m.
Results and Discussion
First, the microdisk laser and the p-i-n photodiode were fabricated and studied separately. The microlaser demonstrates single-mode emission near 1.1 ^m. As detected by an external Ge power meter, the free space output optical power increases almost linearly up to 12 mW limited by the thermal roll-over at 120 mA (Fig. 2). In 30 ^m in diameter bonded microdisk laser the maximum -3-dB modulation frequency of 8.2 GHz was found. The InGaAs/GaAs QWDs p-i-n photodiodes with low dark current (2.1 ^A/cm2) and sensitivity up to 1.12 ^m spectral range were demonstrated.
Fig. 2. Light-current characteristic of the bonded 30 ^m in diameter disk microlaser obtained at 20 °C.
Inset: photocurrent of the photodiode integrated with microlaser at different laser pumping current
Next, the microlaser and photodetector were integrated onto Si substrate using Au-Au thermocompressive bonding. Epi-side down bonding of the microdisk laser to a silicon substrate significantly (~ 2 times) decreases the thermal resistance and improves continuous-wave and dynamic characteristics. The photocurrent of the photodiode integrated with microlaser versus the MD pumping current and PD reverse bias were studied (inset in Fig. 2). The maximum link efficiency determined as the ratio of the photodiode photocurrent increment to the increment of the microlaser bias current was up to 1.4%.
Since the active region of the photodiode consists of ten stacked InGaAs/GaAs quantum well-dots structures it can be used as an amplifying medium for the light transferring in the photodiode waveguide. We have measured the photocurrent of the PD integrated with the microlaser versus the MD pumping current also applying pumping current to PD. To test the amplification effect, we excluded photocurrent induced by the PD emission itself (Fig. 3). We observe the increase of the photodiode photocurrent with the maximum photocurrent increment value ~ 40 ^A. Obviously, such a small increment is caused not so much by amplification as by the gradual transparency of the InGaAs/GaAs quantum well-dots active region.
100
Current (mA)
Fig. 3. Photocurrent of the PD integrated with microlaser versus the MD pumping current obtained
at various PD photocurrents
Conclusion
To conclude, we have studied microdisk laser and the p-i-n photodiode integrated on a silicon substrate by Au-Au thermocompression bonding to transceiver. The maximum link efficiency determined as the ratio of photocurrent increment to the increment of the microlaser bias current was to complicate far-field intensity distribution of the microdisk laser only a the emission falls on the receiving area of the photodetector. The response by the directional MD laser emission output and proper vertical alignment and the waveguide PD.
Acknowledgments
Electron-microscopy studies were performed using the equipment of the "Materials Science and Diagnostics in Advanced Technologies" Federal Center for Collective Use.
heterogeneously form a compact the photodiode up to 1.4%. Due small fraction of can be improved of the MD laser
REFERENCES
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2. Toropov N., Cabello G., Serrano M. P., Gutha R. R., Vollmer F., Review of biosensing with whispering-gallery mode lasers, Light: Science and Application. 10 (2021) article number 42.
3. Vlasov Y. A., McNab S. J., Losses in single-mode silicon-on-insulator strip waveguides and bends, Optics Express. 12 (8) (2004) 1622-1631.
4. Liu A., Jones R., Liao L., Samara-Rubio D., Rubin D., Cohen O., Nicolaescu R., Paniccia M., A high-speed silicon optical modulator based on a metal-oxide-semiconductor capacitor, Nature. 427 (2004) 615-618.
5. Cao V., Park J.-S., Tang M., Zhou T., Seeds A., Chen S, Liu H., Recent Progress of Quantum Dot Lasers Monolithically Integrated on Si Platform, Frontiers in Physics: Optics and photonics. 10 (2022) 839953. doi: 10.3389/fphy.2022.839953.
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Experimental technique and devices
THE AUTHORS
KRYZHANOVSKAYA Natalia V.
nataliakryzh@gmail.com ORCID: 0000-0002-4945-9803
fedyazu@mail.ru
ORCID: 0000-0002-3926-8675
ZUBOV Fedor I.
MOISEEV Eduard I.
emoiseev@hse.ru
ORCID: 0000-0003-3686-935X
KULAGINA Marina M. Marina.Kulagina@mail.ioffe.ru
ORCID: 0000-0002-8721-185X
DRAGUNOVA Anna S.
anndra@list.ru
ORCID: 0000-0002-0181-0262
GUSEVA Yulia A.
Guseva.Julia@mail.ioffe.ru ORCID: 0000-0002-7035-482X
MAXIMOV Mikhail V.
LIKHACHEV Alexey I.
lihachev_alexey@bk.ru ORCID: 0000-0003-1639-3382
maximov.mikh@gmail.com ORCID: 0000-0002-9251-226X
KALYUZHNYY Nikolay A.
Nickk@mail.ioffe.ru ORCID: 0000-0001-8443-4663
ZHUKOV Alexey E.
zhukale@gmail.com ORCID: 0000-0002-4579-0718
MINTAIROV Sergey A. mintairov@scell.ioffe.ru ORCID: 0000-0002-6176-6291
Received 08.08.2022. Approved after reviewing 21.08.2022. Accepted 24.08.2022.
© Peter the Great St. Petersburg Polytechnic University, 2022
