Voltage controlled attenuator
AssigneeJDS Fitel Inc.
InventorsCarey Marcel Garrett, Chenjun Fan, Darko Cugalj, David Gransden
Life of this patent
Estimating the term…
Abstract
A voltage controlled attenuator for an optical telecommunication system comprises an optical attenuator placed between an input and an output lens for obstructing the path of an incoming light beam. The attenuator has variable attenuation (reflection, absorption, etc.) which is controlled for maintaining a preset power of the outgoing light beam. To this end, a fraction of the outgoing signal is diverted to an output detector by reflecting off an end face of a lens, and processed for obtaining a control signal representative of the output power. The control signal actuates a dc motor which displaces the attenuator to a position corresponding to a preset output power.
Claims25
An attenuating device comprising:
- a first lens for receiving an incoming light beam and for directing said light beam along a first beam path;
- a second lens disposed along said first beam path having an input face arranged so that substantially most of said light beam incident upon said input face passes therethrough said second lens as an outgoing light beam, while a smaller, predetermined portion of said light beam is reflected off an end face thereof along a reflected beam path;
- optical detection means disposed to receive said predetermined portion for detecting the intensity of said predetermined portion;
- and controllable attenuating means located between said first lens and said second lens, and being in or movable in said optical path for varying the attenuation of said outgoing light beam.
A miniature package comprising:
- a first lens for receiving an incoming light beam and for transmitting a light beam along a first beam path;
- a second lens disposed along said first beam path for receiving said light beam and reflecting a small fraction of said light beam off said input face along a second beam path;
- optical detection means disposed in said second path for receiving said fraction and detecting the intensity of said fraction;
- controllable attenuating means arranged in said first path for attenuating the intensity of said light beam;
- a dc motor receiving said control signal and rotating a central shaft accordingly;
- a disk fixed to said central shaft for rotation therewith and having a pin fixed on the surface of said disk;
- a lever with a first end coupled to said pin and hinged at the other end;
- and
- means for attaching said optical attenuator to said lever for moving said attenuating means.
An optical attenuator for integration into an optical fiber transmission system comprising:
- an input lens for receiving an incoming light beam at an input end and transmitting a collimated beam at an output end;
- an attenuating element placed in or movable in the path of said collimated beam for providing an attenuated light beam;
- an output lens for receiving said attenuated beam, transmitting an outgoing light beam, said output lens being provided with reflective means for reflecting a predetermined fraction of said outgoing light beam;
- and
- driving means for displacing said attenuating element to a target position in response to a control signal obtained from said fraction.
Dependencies are inferred from the claim text.