Reflective modular a 'missing link'

CIP Technologies in Britain has released what is believed to be the first commercial reflective electro-absorption modulator.

The launch provides developers of access network and other communications applications with the means to implement innovative system architectures.

Among many potential applications for the reflective electro-absorption modulator (R-EAM) are 10 Gbps wavelength division multiplexing passive optical networks and a simple means of linking radio antennas to a high-speed optical cable — to extend the coverage of high data rate wireless technologies.

The InP (indium phosphide) device, the R-EAM-1550-LS, has been designed to suit high volume production.

It operates in the C band (1550 nm) and has a low optical insertion loss of 3.5 dB typical. It will also operate with low drive voltages and has low polarisation dependent loss (0.3 dB typical).

Numerous design features on the die have been incorporated to optimise manufacturability and yield and simplify coupling to optical fibre.

This economy is aided by the device's need for only a single optical fibre connection. The device also dissipates very little power and will operate uncooled in some configurations, reducing the total electrical power for many target applications.

One of the biggest potential applications for R-EAMs is in fibre-to-the-home/premises access network architectures. The component provides high-speed transmission capability by reflecting and modulating a 'seed' light that is transmitted to the network and will comfortably operate at data rates up to 10 Gbps as will be needed in next-generation optical access networks.

Light from the multi-wavelength seed source can be split into different wavelengths for use in different segments of the network by means of an arrayed waveguide grating — a readily available component.

The architecture allows a R-EAM to deliver dedicated multi-gigabit optical data transmission facilities for clients without the expense of a tuneable waveguide source. In addition to minimising the costs of the bidirectional fibre-optic assembly required for client premises, this approach allows one standard BIDI to be manufactured and installed for all users.

The R-EAM-1550-LS expands the architectural possibilities of WDM-PON to users requiring operation at 10 Gbps.

A second major application for R-EAMs can be found in wireless networks where it makes possible to extend the coverage of a wireless access point with a network of remote antennas.

A single fibre-optic cable could support 32 antennas operating on different wavelengths for example, providing a low-cost means of extending the coverage of short-range, high data rate wireless technologies around a building or plant.

Because of the passive way in which R-EAMs can operate, the cost of remote nodes in this application could be small, as in their simplest form they can be fabricated with just a R-EAM and a simple antenna and operate without any need for local power.

As it will also operate as a photodiode, these passive nodes can provide both uplink and downlink capabilities.