| 1. |
- Anand, Srinivasan, et al.
(författare)
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High aspect ratio etching and characterization of 2D-photonic crystals in InP/InGaAsP/InP heterostructures
- 2004
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Ingår i: Photonics. - : SPIE - International Society for Optical Engineering. - 0819451703 ; , s. 78-89
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Konferensbidrag (refereegranskat)abstract
- We report on the fabrication and characterization of 2D photonic crystals (PhCs) in InP/InGaAsP/InP heterostructures. It is demonstrated that Ar/C12 based chemically assisted ion beam etching (CAIBE) is a very promising method to obtain high aspect ratio etching of PhCs in the InP-based materials. With this process, it is possible to obtain PC-holes as deep as 3 microns even for feature (PhC-hole) sizes as small as 200-250 nm. The optical characteristics of the fabricated PhC-based elements/devices such as line-defect waveguides, in-plane resonant cavities and drop-filter based on contra-directional coupling will be reported. The devices were measured using end-fire coupling and the obtained results were simulated using the 2D finite difference time domain (FDTD) method including an effective loss-approximation. The etched PhC-waveguides show low transmission losses, less than 1 dB/100 mum. A quality factor of 400 for a 6 micron long cavity with 6-hole mirrors is obtained. Finally, drop-functionality in a PhC-based filter using contra-directional coupling is demonstrated.
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| 2. |
- Irmscher, Stefan, et al.
(författare)
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High-speed electro-absorption modulators for fiber-optic communications
- 2004
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Ingår i: Photonics. - : SPIE - International Society for Optical Engineering. - 0819451703 ; , s. 29-41
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Konferensbidrag (refereegranskat)abstract
- Features such as large bandwidth, low drive voltage, compact size, and feasibility for monolithic laser integration make electro-absorption modulators (EAM) attractive candidates for ultra high-speed fiber-optical time division multiplexing (TDM). EAM with traveling-wave (TW) electrodes have successfully been demonstrated as a way to considerably increase the modulation bandwidth without sacrificing modulation efficiency. However, for reasonable modulation efficiency a low characteristic impedance (25Omega) has to be accepted. Termination with a matched load is necessary to benefit from the TW configuration. Thus, TWEAM with continuous impedance-matched transmission lines (TML) provide very high bandwidths, but suffer from high electrical return loss when using a 50Omega driver. A solution to this problem is to split up the modulator and insert passive TML segments between the active parts. The passive segments can be designed for a higher characteristic impedance than the active modulator parts with their inherently low impedance. In this way, the impedance seen at the electrical modulator input can be tailored for values that deliver optimum performance in combination with the available driving electronics (usually 50Omega). Only little bandwidth is sacrificed with the segmented design. Recently; we have demonstrated state-of-the-art performance of segmented TWEAM. These devices exhibit low electrical return loss (<-15dB) and a flat small signal modulation response in the characterized frequency range of 0.04 to 50GHz. 50Gb/s operation is demonstrated. An extinction of 10dB with 3Vp-p is achieved at 40Gb/s.
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