Изготовление и характеристика фотонного кристалла медленно волноводы Света и полостей
Summary
Использование фотонных кристаллов медленный волноводы света и полости была широко принята сообществом фотоники во многих различных приложениях. Поэтому изготовления и характеристики этих устройств представляют большой интерес. В настоящем документе излагается наша техника изготовления и два оптических методов характеристику, а именно: интерферометрических (волноводы) и резонансное рассеяние (полостей).
Abstract
Slow light has been one of the hot topics in the photonics community in the past decade, generating great interest both from a fundamental point of view and for its considerable potential for practical applications. Slow light photonic crystal waveguides, in particular, have played a major part and have been successfully employed for delaying optical signals1-4 and the enhancement of both linear5-7 and nonlinear devices.8-11
Photonic crystal cavities achieve similar effects to that of slow light waveguides, but over a reduced band-width. These cavities offer high Q-factor/volume ratio, for the realization of optically12 and electrically13 pumped ultra-low threshold lasers and the enhancement of nonlinear effects.14-16 Furthermore, passive filters17 and modulators18-19 have been demonstrated, exhibiting ultra-narrow line-width, high free-spectral range and record values of low energy consumption.
To attain these exciting results, a robust repeatable fabrication protocol must be developed. In this paper we take an in-depth look at our fabrication protocol which employs electron-beam lithography for the definition of photonic crystal patterns and uses wet and dry etching techniques. Our optimised fabrication recipe results in photonic crystals that do not suffer from vertical asymmetry and exhibit very good edge-wall roughness. We discuss the results of varying the etching parameters and the detrimental effects that they can have on a device, leading to a diagnostic route that can be taken to identify and eliminate similar issues.
The key to evaluating slow light waveguides is the passive characterization of transmission and group index spectra. Various methods have been reported, most notably resolving the Fabry-Perot fringes of the transmission spectrum20-21 and interferometric techniques.22-25 Here, we describe a direct, broadband measurement technique combining spectral interferometry with Fourier transform analysis.26 Our method stands out for its simplicity and power, as we can characterise a bare photonic crystal with access waveguides, without need for on-chip interference components, and the setup only consists of a Mach-Zehnder interferometer, with no need for moving parts and delay scans.
When characterising photonic crystal cavities, techniques involving internal sources21 or external waveguides directly coupled to the cavity27 impact on the performance of the cavity itself, thereby distorting the measurement. Here, we describe a novel and non-intrusive technique that makes use of a cross-polarised probe beam and is known as resonant scattering (RS), where the probe is coupled out-of plane into the cavity through an objective. The technique was first demonstrated by McCutcheon et al.28 and further developed by Galli et al.29
Protocol
Representative Results
Discussion
Примеры изготовления
Наш выбор электронно-лучевой сопротивление (т.е. ZEP 520A) связано с его одновременно с высоким разрешением и травления сопротивление. Мы считаем, что ZEP 520A могут быть затронуты УФ-света, излучаемого от верхнего освещения лаборатории, как таковой, мы ?…
Disclosures
The authors have nothing to disclose.
Acknowledgements
Авторы выражают благодарность д-р Маттео Галли, д-р Симон Л. Portalupi и профессор Лучио C. Andreani из Университета Павии за полезные обсуждения, связанные с техникой RS и выполнения измерений.
Materials
| Name | Company | Catalogue number | Comments (optional) |
| Acetone | Fisher Scientific | A/0520/17 | CAUTION: flammable, use good ventilation and avoid all ignition sources. |
| Isopropanol | Fisher Scientific | P/7500/15 | CAUTION: flammable, use good ventilation and avoid all ignition sources. |
| Electron Beam resist | Marubeni Europe plc. | ZEP520A | CAUTION: flammable, harmful by inhalation, avoid contact with skin and eyes. |
| Xylene | Fisher Scientific | X/0100/17 | CAUTION: flammable and highly toxic, use good ventilation, avoid all ignition sources, avoid contact with skin and eyes. |
| Microposit S1818 G2 | Chestech Ltd. | 10277866 | CAUTION: flammable and causes irritation to eyes, nose and respiratory tract. |
| Microposit Developer MF-319 | Chestech Ltd. | 10058721 | CAUTION: alkaline liquid and can cause irritation to eyes, nose and respiratory tract. |
| Hydrofluoric Acid | Fisher Scientific | 22333-5000 | CAUTION: extremely corrosive, readily destroys tissue; handle with full personal protective equipment rated for HF. |
| Microposit 1165 Remover | Chestech Ltd. | 10058734 | CAUTION: flammable and causes irritation to eyes, nose and respiratory tract. |
| Sulphuric Acid | Fisher Scientific | S/9120/PB17 | CAUTION: corrosive and very toxic; handle with personal protective equipment and avoid inhalation of vapours or mists. |
| Hydrogen Peroxide | Fisher Scientific | BPE2633-500 | CAUTION: very hazardous in case of skin and eye contact; handle with personal protective equipment. |
| Equipment | |||
| Silicon-on-Insulator wafer | Soitec | G8P-110-01 | |
| Diamond Scribe | J & M Diamond Tool Inc. | HS-415 | |
| Microscope slides | Fisher Scientific | FB58622 | |
| Beakers | Fisher Scientific | FB33109 | |
| Tweezers | SPI Supplies | PT006-AB | |
| Ultrasonic Bath | Camlab | 1161436 | |
| Spin-Coater | Electronic Micro Systems Ltd. | EMS 4000 | |
| Pipette | Fisher Scientific | FB55343 | |
| E-beam Lithography System | Raith Gmbh | Raith 150 | |
| Reactive Ion Etching System | Proprietary In-house Designed | — | |
| UV Mask Aligner | Karl Suss | MJB-3 | |
| ASE source | Amonics | ALS-CL-15-B-FA | CAUTION: invisible IR radiation. |
| Single mode fibers | Thorlabs | P1-SMF28E-FC-2 | |
| 3 dB fiber splitters | Thorlabs | C-WD-AL-50-H-2210-35-FC/FC | |
| Aspheric lenses | New Focus | 5720-C | |
| XYZ stages | Melles Griot | 17AMB003/MD | |
| Polarizing beamsplitter cube | Thorlabs | PBS104 | |
| IR detector | New Focus | 2033 | |
| 100× Objective | Nikon | BD Plan 100x | |
| Oscilloscope | Tektronix | TDS1001B | |
| Optical Spectrum Analyzer | Advantest | Q8384 | |
| IR sensor card | Newport | F-IRC2 | |
| TLS source | Agilent | 81940A | CAUTION: invisible IR radiation. |
| IR Camera | Electrophysics | 7290A | |
| IR Detector | New Focus | 2153 | |
| Digital Multimeter | Agilent | 34401A | |
| Illumination | Stocker Yale | Lite Mite | |
| Monochromator | Spectral Products | DK480 | |
| Array Detector | Andor | DU490A-1.7 | |
| GIF Fiber | Thorlabs | 31L02 |
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