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Multicolor Fluorescence Detection for Droplet Microfluidics Using Optical Fibers

Multicolor Fluorescence Detection for Droplet Microfluidics Using Optical Fibers

Published on: May 5, 2016

Coherent detection in optical fiber systems.

Ezra Ip¹, Alan Pak Tao Lau, Daniel J F Barros

¹Stanford University, 366 Packard Building, 350 Serra Mall, Stanford, CA 94305-9515, USA. wavelet@stanford.edu

|June 11, 2008

Summary

This summary is machine-generated.

Coherent detection in optical fiber systems offers high performance by utilizing all four degrees of freedom (DOF). Digital signal processing (DSP) enables compensation for impairments, paving the way for 100 Gbit/s receivers.

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Area of Science:

Optical Communications
Signal Processing

Background:

Higher performance demands in optical fiber systems drive renewed interest in coherent detection.
Review of noncoherent, differentially coherent, coherent, and hybrid detection methods.

Purpose of the Study:

Compare modulation methods encoding information in various degrees of freedom (DOF).
Highlight polarization-multiplexed quadrature-amplitude modulation for maximizing spectral and power efficiency.
Discuss the role of digital signal processing (DSP) in coherent receivers.

Main Methods:

Utilizing dual-polarization homodyne or heterodyne downconversion to recover signals in four DOF.
Employing Nyquist rate sampling for signal downconversion.
Applying finite impulse response filters for compensating linear impairments like chromatic dispersion and polarization-mode dispersion.
Implementing feedforward methods for carrier phase recovery.

Main Results:

Polarization-multiplexed quadrature-amplitude modulation maximizes spectral and power efficiency by using all four DOF.
DSP enables quasi-exact compensation of linear impairments and partial compensation of nonlinear impairments.
DSP-based compensation allows receivers to adapt to time-varying impairments and utilize advanced forward-error-correction codes.
Both single- and multi-carrier systems with coherent detection offer similar spectral and power efficiency.

Conclusions:

Coherent detection, particularly with DSP, is crucial for advancing optical fiber systems.
DSP-based coherent receivers are expected to become practical at bit rates up to 100 Gbit/s with technological advancements.