Dual mode programmable optical logarithmic amplifier driver

#The present invention relates to electronic controllers for laser optical amplifiers, specifically, controllers having logarithmic amplifiers.

#Rare earth doped optical amplifiers have emerged as the predominant optical signal amplification device in nearly every aspect of optical communication networks spanning from repeaters, pre-amplifiers and power boosters to wavelength division multiplexed (WDM) systems. These amplifiers are suitable for terrestrial, transoceanic, metro/access, cable television, and local area networks. The optical amplifier boosts the optical signal directly in the optical domain without the need for converting the signal into an electrical signal. As modern telecommunication networks increasingly require robustness, flexibility, reconfigurability, and reliability, there is an ever-growing demand for automatically controlled optical amplifier devices.

#In reconfigurable dense wavelength multiplexed (DWDM) systems with optical add-drop multiplexing (OADM), the input signal power undergoes variations as the channel configurations or the operation conditions change. It would be beneficial to provide a stabilized optical amplifier device that automatically adjusts its signal gain, or its signal output power. Furthermore, it would be beneficial to have an optical amplifier which can be dynamically controlled and adjusted by a central system via a standard communication port.

#The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate the presently preferred embodiment of the invention, and, together with the general description given above and the detailed description given below, serve to explain the features of the invention. In the drawings:

#FIG. 1 is a plan view of a dual mode electronic amplifier controller according to the present invention.

#FIG. 2 is a schematic diagram of the dual mode electronic amplifier controller according to the present invention.

#In the drawings, like numerals indicate like elements throughout. A dual mode electronic amplifier controller (hereinafter “controller”) 100 is used in an optical amplifier (not shown) to control the amount of current provided to a pump laser (not shown) in the optical amplifier. Such an optical amplifier is disclosed in U.S. patent application Ser. No. 09/877,760, filed on even date, which is owned by the assignee of the present invention and is incorporated herein by reference in its entirety. As shown in FIG. 1, the controller 100 is preferably disposed on a printed circuit board 102 having approximate dimension of 6.1 mm×11.3 mm.

#Referring to FIG. 2, the controller 100 includes a first, or input logarithmic amplifier (log amp) 110, a second or output logarithmic amplifier (hereinafter “log amp”) 120, a microprocessor 130, a pump laser controller 140, a temperature sensor 150, a thermoelectric cooler (TEC) controller 160, and a power supply connection 170.

#A first signal input 112, electronically connects the input of the first log amp 110 to a first photodetector 20. The first signal input 112 taps a percentage of a preamplified input light signal, preferably approximately one percent, which is converted to a digital electronic signal, and transmits the tapped input light signal to the log amp 110. A first signal output 114 electronically connects the output of the first log amp 110 to the microprocessor 130. The first log amp 110 is electrically connected to the power supply 170 by first log amp power connections 116, 118.