CIP Launches 40GHz 'Optical Sampler'

IPSWICH, U.K. -- The Centre for Integrated Photonics has released a novel component that provides a versatile platform for optical networks employing advanced attributes such as return-to-zero data modulation, pulse shaping, and optical time division multiplexing. Providing a sampling function capable of operating at rates up to 40 GHz in the 1550 nm waveband, the indium-phosphide (InP) device can generate temporal windows of less than 5 picoseconds duration with a low polarisation loss, and fine control over both window shape and frequency. This offers a compact and much more versatile alternative to conventional component options.

Based on an electro-absorption modulator (EAM), the 40G-PS-EAM-1550 device can be used in a wide variety of optical applications. Many current optical network development projects are investigating new architectural concepts including the use of return-to-zero (RZ) data modulation. Here, a simple combination of a low-cost continuous wave laser and CIP's new device can provide narrow RZ pulse trains at rates up to 40 GHz. Pulse frequency may also be varied very widely, supporting the requirements of forward error correction (FEC) techniques.

The component is also ideal for high-speed optical analysis, for dynamic performance monitoring of network signal quality. Unlike some current diagnostic techniques - which can be complex and expensive to implement - this extremely compact device can be used to provide direct information on signal amplitude and phase, providing a solution that can be built into equipment economically.

Another emerging technique for network development is the use of OTDM (optical time division multiplexing). By employing multiple 40G-PS-EAM-1550 devices with a simple passive splitter and delay line arrangement, CIP's new device provides an elegant and cost-effective solution for implementing the full demultiplexing function required at the end of an OTDM link. Possible demultiplexing rates include 160 to 40 Gbits/sec, 160 to 10 Gbits/sec, and 40 to 10 Gbits/sec.

Among the major performance characteristics of the 40G-PS-EAM-1550 device for 1550 nm applications is the ability to generate temporal optical sampling windows with a FWHM (full wave half maximum) duration of less than 5 picoseconds, a polarisation dependent loss of typically 0.7 dB, and a modulation depth of 28 dB typical. The device's non-linear absorption characteristics additionally give engineers excellent control over output pulse shape.

Fabricated using multiple quantum well technology, the indium phosphide device is packaged with input and output fibres and is provided with a K or V style high speed electrical connector as required. It is available for immediate delivery in small quantities. It may also be provided in a custom designed package with TEC if required.

The new EAM-based device joins a comprehensive range of compound-semiconductor and planar lightwave circuit device functions for optical networking developed over many years by CIP. CIP has a long pedigree in optoelectronics and materials, having previously been part of Corning, and before that British Telecom's Photonic Technology Research Centre. The organisation has its own semiconductor fabrication plant and is able to create variants of this EAM with application-specific performance, including integrated arrays of devices, if required.

Centre for Integrated Photonics (CIP) Ltd.