Options, feasibility, and availability of 2 /spl times/ 4 90/spl deg/ hybrids for coherent optical systems

Seimetz, Matthias; Weinert, C.M.

doi:10.1109/jlt.2005.863251

Cited by 101 publications

(44 citation statements)

References 11 publications

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“…These hybrids have been realized in all-fibre, 31 planar waveguide, [32][33][34] and free-space bulk optics 35 formats. Out of these, optical hybrids based on photonic light wave circuits offer compactness, low cost, and stable operation.…”

Section: B Wavelength Encoder Unitmentioning

confidence: 99%

Towards the development of a hybrid-integrated chip interferometer for online surface profile measurements

Kumar

Martin

Jiang

2016

Review of Scientific Instruments

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Non-destructive testing and online measurement of surface features are pressing demands in manufacturing. Thus optical techniques are gaining importance for characterization of complex engineering surfaces. Harnessing integrated optics for miniaturization of interferometry systems onto a silicon wafer and incorporating a compact optical probe would enable the development of a handheld sensor for embedded metrology applications. In this work, we present the progress in the development of a hybrid photonics based metrology sensor device for online surface profile measurements. The measurement principle along with test and measurement results of individual components has been presented. For non-contact measurement, a spectrally encoded lateral scanning probe based on the laser scanning microscopy has been developed to provide fast measurement with lateral resolution limited to the diffraction limit. The probe demonstrates a lateral resolution of ∼3.6 μm while high axial resolution (sub-nanometre) is inherently achieved by interferometry. Further the performance of the hybrid tuneable laser and the scanning probe was evaluated by measuring a standard step height sample of 100 nm.

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Section: B Wavelength Encoder Unitmentioning

confidence: 99%

Towards the development of a hybrid-integrated chip interferometer for online surface profile measurements

Kumar

Martin

Jiang

2016

Review of Scientific Instruments

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“…As a result, any optical hybrid based on 4 Â 4-MMIs will most likely exhibit this kind of self-compensating effect, independently of the technology. However, it might not be necessarily true for other types of hybrids, such as those based on directional couplers and waveguide phase shifters [4] or interleavedchirped AWGs [5], which would require additional investigation. Note also that this improvement is independent of the relative power between the LO and the signal since it only depends on the optical response of the hybrid (that is, the relative phases and amplitudes between the different input and output ports).…”

Section: System Level Evaluationmentioning

confidence: 99%

“…90 optical hybrids are undoubtedly one of the key building blocks that comprise an integrated coherent receiver. Although several configurations for these devices have been proposed and demonstrated so far [4], [5], MMI-based 90 optical hybrids have recently attracted considerable research attention since they offer superior performance in terms of size, operation bandwidth, and polarization independence. By means of a careful design, devices operating over the full C band while keeping low common-mode rejection ratios (CMRRs $ À20 dBe) and phase errors ðÁ err $ AE5 Þ have been demonstrated, both in InP and SOI technologies [5]- [13].…”

Section: Introductionmentioning

confidence: 99%

Dual Photonic Generation Ultrawideband Impulse Radio by Frequency Shifting in Remote-Connectivity Fiber

Beltrán

Llorente

2011

J. Lightwave Technol.

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A numerical study of the impact that manufacturing tolerances have on the performance of an InP 4 Â 4 MMI working as a 90 optical hybrid is presented, including simultaneous variations of width, thickness, and refractive index over the C and L bands. Simulation results for different figures of merit, such as optical common-mode rejection ratios (CMRRs) and phase errors, are provided for both nominal and worst case scenarios. Additionally, system simulations are performed to compute imbalance-induced power penalty. Our results indicate that the combined effect of realistic foundry tolerances on device performance is significant. In particular, a fourfold reduction is predicted between nominal ('40 nm) and worst cases ('10 nm) when optical CMRRs and phase errors are compared against Optical Internetworking Forum specifications. By contrast, a much greater bandwidth is expected at the system level (! 40 nm) if a power penalty of less than 1 dB ð@BER ¼ 10 À3 Þ is to be allowed. In fact, worst case power penalties lower than 0.25 dB are predicted over the full C band, which further proves the great potential of integrated 4 Â 4 MMIs as wide-bandwidth devices for mass production of coherent receivers using state-ofthe-art integration technologies.

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“…When used in WDM systems, coherent receivers offer tunability and enable very small channel spacing, since channel separation can be performed by high-selective electrical filtering. The main challenges for the practical realization of coherent receivers are the implementation of high-speed analog-to-digital converters, real-time carrier synchronization, electronic equalizers as well as the low cost fabrication of the optical key components like the optical 2 Â 4 90 -hybrid (Seimetz, Weinert, 2006). Figure 1 illustrates the constellation diagrams of some selected higher-order modulation formats.…”

Section: State Of the Artmentioning

confidence: 99%

Next generation optical networks based on higher-order modulation formats, coherent receivers and electronic distortion equalization

Seimetz

Freund

2008

Elektrotech. Inftech.

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Die Untersuchung von höherwertigen Modulationsverfahren und innovativen Systemkonzepten zur Steigerung der spektralen Effizienz in optischen Transportnetzen ist derzeit ein wichtiges Forschungsthema. Schlüsseltechnologien zur Erreichung hoher spektraler Effizienz bei gleichzeitig großer Übertragungsreichweite sind insbesondere kohärente Empfänger und digitale elektronische Entzerrer Der Artikel gibt einen Überblick über den Stand der weltweiten Forschungsaktivitäten auf diesem Gebiet

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Options, feasibility, and availability of 2 /spl times/ 4 90/spl deg/ hybrids for coherent optical systems

Cited by 101 publications

References 11 publications

Towards the development of a hybrid-integrated chip interferometer for online surface profile measurements

Towards the development of a hybrid-integrated chip interferometer for online surface profile measurements

Dual Photonic Generation Ultrawideband Impulse Radio by Frequency Shifting in Remote-Connectivity Fiber

Next generation optical networks based on higher-order modulation formats, coherent receivers and electronic distortion equalization

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