Nortel Networks Corporation

Other

Oclaro Technology Limited

Ii-Vi Laser Enterprise Gmbh

Jonathan Stuart Drake

Barrie Flintham

Nadhum Kadhum Zayer

James Regan

Jonathan W Gill

Wenfei Hu

Graeme A Henderson

According to a first aspect of the present invention there is provided an apparatus for performing power equalization and phase correction of two signals (). The apparatus comprises a first hybrid coupler () configured to operate as a power combiner, and a second hybrid coupler () configured to operate as a power divider, wherein the apparatus is configured to provide an output () of the first hybrid coupler as an input () to the second hybrid coupler.

Apparatus for power equalisation and phase correction

There is disclosed an electronic apparatus comprising a chip within a casing. A thermoelectric cooler has thermal connections to the chip and the casing and is configured to transport heat from the chip to the casing. A temperature measuring device is provided for determining the temperature of the chip. A control system is configured to maintain the chip at a target temperature by controlling current supplied to the thermoelectric cooler in response to the measured temperature. A temperature selection system is configured to select the chip target temperature dynamically on the basis of the casing temperature.

Component temperature control

An optical amplifier comprises a doped fiber and a pump source for providing pump light to the fiber. A power measurement circuit is provided for measuring the output power of the amplifier and a disable circuit is controlled to disable the pump source in response to the output power of an output pulse exceeding a predetermined limit. In this way, power surges can be avoided. Preferably, the predetermined limit takes into account the duration of the output pulse, so that the disable circuit can be tailored to pulse power versus pulse duration standardised limits.

Optical amplifier pump control

An optical amplifier comprises: at least first and second amplifier stages, each stage comprising a doped fiber and a pump source for providing pump light to the fiber. The input and output power of the amplifier is measured to enable automatic gain control. The input and output power is processed in order to derive target pump source levels for achieving a substantially constant gain, and the temporal response of the gain control loop is varied in dependence on the target pump source levels. The response time of the gain control loop is thus matched to the open loop gain of the amplifier, taking into account the combination and settings of the amplifier stages.

Optical amplifier gain control

An optical amplifier comprises a pumped doped fiber with a power measurement circuit for measuring the input and output power of the amplifier. Automatic gain control is implemented, and the calculation of output power for the AGC loop takes into consideration the temperature provided by a temperature measurement device. This enables a flatter gain response to be achieved over varying input power, which enables an increase in the dynamic range of the amplifier and thereby a possible increase in system capacity of a WDM system using the amplifier.

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Devon, United Kingdom

Jonathan Stuart Drake