E.J. Klein

Reconfigurable optical add-drop multiplexer using microring resonators

We report a reconfigurable four-channel optical add-drop multiplexer for use in access networks. The optical add-drop multiplexer (OADM) is based on vertically coupled thermally tunable Si/sub 3/N/sub 4/--SiO/sub 2/ microring resonators (MRs) and has been realized on a footprint of 0.25 mm/sup 2/. Individual MRs in the OADM can be tuned across the full free-spectral range of 4.18 nm and have a 3-dB bandwidth of 50 GHz.

Microresonators As Building Blocks For VLSI Photonics

In the last years much effort has been taken to arrive at optical integrated circuits with high complexity and advanced functionality. For this aim high index contrast structures are employed resulting in photonic wires in conventional index guiding waveguides or in photonic bandgap structures. In both cases the number of functional elements within a given chip area can be enhanced by several orders of magnitude: VLSI photonics. In this talk optical microresonators are presented as promising basic building blocks for filtering, amplification, modulation, switching and sensing. Active functions can be obtained by monolithic integration or a hybrid approach using materials with thermo‐, electro‐ and opto‐optic properties and materials with optical gain. Examples are mainly taken from work at MESA+.

Densely integrated microring resonator based photonic devices for use in access networks

Two reconfigurable optical add-drop multiplexers, operating in the second or third telecom window, as well as a 1x4x4 reconfigurable lambda-router operating in the second telecom window, are demonstrated. The devices have a footprint less than 2 mm(2) and are based on thermally tunable vertically coupled microring resonators fabricated in Si(3)N(4)/SiO(2).

Compact wavelength-selective switch for gigabit filtering in access networks

A compact [200/spl times/200 /spl mu/m/sup 2/] wavelength-selective switch based on thermally tunable SiO/sub 2/--Si/sub 3/N/sub 4/ microring resonators has been designed and realized. The switch supports gigabit filtering applications in access networks. Spectral measurements show an ON-OFF ratio of 12 dB and a channel separation of 20 dB. The 10-Gb/s measurements on a single ring show no degradation of the modulated signal and a theoretical BER (bit-error rate) <10/sup -12/.

High-Bit-Rate Dynamically Reconfigurable WDM–TDM Access Network

The intensification of traffic in the access network requires the development of novel architectural solutions for a reconfigurable network topology and components based on optical technologies. We present a hybrid ring-shaped wavelength division multiplexing (WDM)-time division multiplexing (TDM) passive optical network (PON) that is capable of providing bandwidth on demand at high bit rates in a transparent and dynamic manner. Our cost-efficient and scalable network architecture is based on integratable components such as a wavelength-agile optical networking unit and a microring-resonator-based remote node. An appropriately modified control layer is introduced to manage the network. We also discuss the implementation of optical codes instead of time slots to take the step toward optical code division multiplexing (OCDM) WDM PONs that relieve the network of strict time scheduling of traffic and ranging. Therefore, an additional reduction of complexity in network management, improvement of network scalability, and a guarantee of fully symmetric traffic are foreseen for every user. Finally, we show a scenario for smooth migration from existing PON solutions to our WDM-TDM PON architecture.

Large-scale integrated optics using TriPleX waveguide technology: from UV to IR

We present a new class of low-loss integrated optical waveguide structures as CMOS-compatible industrial standard for photonic integration on silicon or glass. A TriPleXTM waveguide is basically formed by a -preferably rectangular- silicon nitride (Si3N4) shell filled with and encapsulated by silicon dioxide (SiO2). The constituent materials are low-cost stoichiometric LPVCD end products which are very stable in time. Modal characteristics, birefringence, footprint size and insertion loss are controlled by design of the geometry. Several examples of new applications will be presented to demonstrate its high potential for large-scale integrated optical circuits for telecommunications, sensing and visible light applications.

25 kHz narrow spectral bandwidth of a wavelength tunable diode laser with a short waveguide-based external cavity

We report on the spectral properties of a diode laser with a tunable external cavity mirror, realized as an integrated optics waveguide circuit. Even though the external cavity is short compared to that of other narrow bandwidth external cavity lasers, the spectral bandwidth of this tunable laser is as small as 25 kHz (FWHM). The side-mode suppression ratio (SMSR) is 50 dB. The laser is able to access preset wavelengths in 200 μs and can be tuned over the full telecommunications C-band (1530–1565 nm).

TriPleX waveguide platform: low-loss technology over a wide wavelength range

In this article a selection of highlights of the TriPleX™ technology of LioniX is given. The basic waveguide technology is explained with recent benchmark measurements done by University California Santa Barbara (UCSB) and University Twente (UT-TE). In order to show the low loss transparency over a wide wavelength range three examples of applications in different wavelength regimes are described in more detail. These are the Integrated Laser Beam Combiner (ILBC) of XiO Photonics in the visible light, a ringresonator sensing platform of LioniX around 850 nm and a phased array antenna with an Optical Beam Forming Network in the 1550 nm band. Furthermore it is shown that the technology is easily accessible via Multi Project Wafer Runs for which the infrastructure and design libraries are also set up.

1.25 - 10 Gbit/s Reconfigurable Access Network Architecture

In this paper we propose a novel reconfigurable access network architecture which enables the bidirectional transmission of 1.25 - 2.5 Gbit/s. Optical network units (ONUs) are equipped with a reflective semiconductor optical amplifier (RSOA) and remote nodes (RNs) are based on microring resonators - both contribute to network transparency and flexibility. We also propose ONU upgrade to serve 10 Gbit/s per end-user. Next to the theoretical description and transmission simulations some principle measurement results are presented which show the feasibility of the concept.

Wavelength-selective switch using thermally tunable microring resonators

A novel wavelength-selective switch based on thermally tunable Si/sub 3/N/sub 4/ microring resonators has been designed, realized and characterized. The switch has an ON/OFF ratio of 7.5 dB and is made out of two rings which allow nearly full dropping (83%) and can thermally be tuned over 3 nm.