Microring resonators side coupled to signal waveguides provide compact, narrow band, and large free spectral range optical channel dropping filters. Higher order filters with improved passband characteristics and larger out-of-band signal rejection are realized through the coupling of multiple rings. The analysis of these devices is approached by the novel method of coupling of modes in time. The response of filters comprised of an arbitrarily large dumber of resonators may be written down by inspection, as a continued fraction. This approach simplifies both the analysis and filter synthesis aspects of these devices.

Microring resonator channel dropping filters

The very broad bandwidth of low-loss optical transmission in a single-mode fiber and the recent improvements in single-frequency tunable lasers have stimulated significant advances in dense wavelength division multiplexed optical networks This technology, including wavelength-sensitive optical switching and routing elements and passive optical elements, has made it possible to consider the use of wavelength as another dimension, in addition to time and space, in network and switch design The independence of optical signals at different wavelengths makes this a natural choice for multiple-access networks, for applications which benefit from shared transmission media, and for networks in which very large throughputs are required Recent progress in multiwavelength networks are reviewed, some of the limitations which affect the performance of such networks are discussed, and examples of several network and switch proposals based on these ideas are presented Discussed also are critical technologies that are essential to progress in this field >

Dense wavelength division multiplexing networks: principles and applications

Wavelength multiplexers, demultiplexers and routers based on optical phased arrays play a key role in multiwavelength telecommunication links and networks. In this paper, a detailed description of phased-array operation and design is presented and an overview is given of the most important applications.

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PHASAR-based WDM-devices: Principles, design and applications

An overview of emerging all-optical networks is given. The characteristics and alternative architectures for single-hop systems are discussed. The characteristics of lightwave technology that facilitate the design of wavelength-division-multiplexing (WDM) networks are reviewed, and it is explained how WDM local networks can be built based on the single-hop and multihop approaches. Various categories of single-hop systems are discussed: experimental systems, systems based on no pretransmission coordination, and systems based on pretransmission coordination, which also require a separate control channel. A simple classification for single-hop systems is provided. >

WDM-based local lightwave networks. I. Single-hop systems

We review photonic applications of dielectric whispering-gallery mode (WGM) resonators-tracing the growth of the technology from experiments with levitating droplets of aerosols to ultrahigh-Q solid state crystalline and integrated on-chip microresonators.

Optical resonators with whispering-gallery modes-part II: applications

A wide free-spectral-range (FSR) waveguide double-ring resonator (DRR) is investigated for use in optical frequency-division multiplexing (OFDM) transmission systems. It consists of two ring resonators with different radii and three directional couplers. The FSR is determined by the least common multiple of the FSRs of the two ring resonators. In order to determine the parameters of the DRR, transmission equations of the DRR, which have different radii, are derived by using the scattering matrix. The dependence of the transmittance characteristics of the DRR on the amplitude coupling coefficients of directional couplers and on the propagation loss of the ring waveguides is studied. The design guidelines for OFDM transmission systems are described. >

A wide-FSR waveguide double-ring resonator for optical FDM transmission systems

Polarization-independent frequency conversion over a 1-THz range by fiber four-wave mixing is demonstrated using a polarization diversity technique. The power of the converted light varies less than 0.2 dB. Bit-error-rate (BER) performance of frequency-shift-keying (FSK) direct detection at 622 Mb/s confirms the feasibility of the technique. >

Polarization independent frequency conversion by fiber four-wave mixing with a polarization diversity technique

The influence of fiber four-wave mixing on multichannel transmissions is investigated We present strict and approximate theoretical treatments for evaluating power penalty with intensity-modulated/direct-detection (IM/DD) and FSK/direct detection A comparison of calculations shows that both methods yield the same result in the small penalty region Using these treatments, power penalty and allowable fiber input power are derived for various system conditions It is shown that the power penalty is not uniquely determined by the crosstalk level for CW lights, depending on the demodulation scheme and channel spacing, especially in the zero-dispersion wavelength region >

Crosstalk and power penalty due to fiber four-wave mixing in multichannel transmissions

A 100-channel optical frequency-division multiplexing (FDM) transmission/distribution experiment at 622 Mb/s is demonstrated for a fiber length of 50 km. The feasibility of a polarization-insensitive waveguide frequency selection switch for 10-GHz intervals and a frequency-shift-keying (FSK) direct-detection scheme employing a Mach-Zehnder filter is verified. The demodulation circuit employs a Mach-Zehnder filter and a balanced receiver, which utilizes optical power more efficiently than the Fabry-Perot filter. No receiver sensitivity degradation is observed due to interchannel crosstalk of the 128-channel tunable waveguide frequency selection switch (FS-SW) or fiber four-wave mixing for transmissions over a 50-km-long nondispersion-shifted (NDS) fiber and a 26-km-long dispersion-shifted (DS) fiber. >

A 100-channel optical FDM transmission/distribution at 622 Mb/s over 50 km

A wide-band guided-wave periodic multi/demultiplexer with a ring resonator for optical frequency-division-multiplexing (FDM) transmission systems is demonstrated. This periodic multi/demultiplexer consists of a Mach-Zehnder interferometer and ring resonator. It has a flat wide bandwidth and sharp cutoff regions. The authors describe theoretical analysis, design method, and experimental results of the multi/demultiplexer. The fabricated periodic multi/demultiplexer with a ring resonator has 5-GHz channel frequency separation at the 1.55- mu m wavelength region. Measured average loss was 4.8-dB and the average crosstalk was -13.2 dB. At 0.5-dB loss up from the minimum loss level, a width of 4.0 GHz was measured. This '0.5-dB bandwidth' is 1.8 times wider than that of the conventional Mach-Zehnder type periodic multi/demultiplexer. >

Kazuhiro Oda

Papers

A wide-FSR waveguide double-ring resonator for optical FDM transmission systems

Polarization independent frequency conversion by fiber four-wave mixing with a polarization diversity technique

Crosstalk and power penalty due to fiber four-wave mixing in multichannel transmissions

A 100-channel optical FDM transmission/distribution at 622 Mb/s over 50 km

A wide-band guided-wave periodic multi/demultiplexer with a ring resonator for optical FDM transmission systems