Output power monitoring in an optical preamplifier
OwnerJerzy Domagala, Scott A. Schubeinventors
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Abstract
Tapless output power monitoring is used when amplifying and converting an optical signal to an electrical signal, e.g., in a communications receiver of an optical transmission system. An optical preamplifier amplifies an intensity-modulated optical input signal to produce an amplified intensity-modulated optical signal. An optical-to-electrical (O-E) converter demodulates and converts the amplified intensity-modulated optical signal into an electrical output signal. A current monitor monitors a DC bias current of the optical-to-electrical (O-E) converter and produces a feedback signal proportional to the DC bias current. The optical preamplifier adjusts the gain of the amplified optical signal based on the feedback signal.
Claims20
A method for tapless output power monitoring in an optical preamplifier including an optical-to-electrical (O-E) converter for demodulating and converting an intensity-modulated optical signal into an electrical output signal, said method comprising:
- monitoring a DC bias current in said O-E converter while said O-E converter demodulates and converts said intensity-modulated optical signal, wherein said DC bias current is directly related to average optical power incident on said O-E converter;
- and
- producing a feedback signal proportional to said DC bias current, wherein said feedback signal is used to adjust said optical preamplifier to provide a substantially constant output power to said O-E converter.
A method for converting an intensity-modulated optical input signal into an electrical output signal, said method comprising:
- amplifying said intensity-modulated optical input signal to produce an amplified intensity-modulated optical signal;
- demodulating and converting said amplified intensity-modulated optical signal into said electrical output signal using an optical-to-electrical (O-E) converter;
- monitoring a DC bias current of said O-E converter used to convert said amplified intensity-modulated optical signal into said electrical output signal;
- producing a feedback signal proportional to said DC bias current;
- and
- adjusting power of said amplified intensity-modulated optical signal based on said feedback signal.
A system for converting an intensity-modulated optical input signal into an electrical output signal, said system comprising:
- means for amplifying said intensity-modulated optical input signal to produce an amplified intensity-modulated optical signal;
- means for demodulating and converting said amplified intensity-modulated optical signal into said electrical output signal;
- means for producing an output power feedback signal without tapping into a portion of said amplified intensity-modulated optical signal;
- and
- means for adjusting power of said amplified intensity-modulated optical signal based on said output power feedback signal.
An optical preamplifier comprising:
- an optical gain medium for receiving an intensity-modulated optical input signal and producing an amplified intensity-modulated optical signal;
- an optical-to-electrical (O-E) converter for demodulating and converting said amplified intensity-modulated optical signal into an electrical output signal;
- a pump laser for pumping said optical gain medium;
- pump bias control circuitry for controlling said pump laser;
- and
- a current monitor for monitoring a DC bias current of said O-E converter and for producing a feedback signal proportional to said DC bias current, wherein said feedback signal is provided to said pump bias control circuitry for adjusting the gain of said optical gain medium.
An optical communications receiver comprising:
- an optical preamplifier for receiving an intensity-modulated optical input signal and producing an amplified intensity-modulated optical signal;
- an optical-to-electrical (O-E) converter for demodulating and converting said amplified intensity-modulated optical signal into an electrical output signal;
- and
- a current monitor for monitoring a DC bias current of said O-E converter and for producing a feedback signal proportional to said DC bias current, wherein said feedback signal is provided to said optical preamplifier for adjusting the gain of said optical preamplifier such that said amplified intensity-modulated optical signal has substantially constant output power.
Dependencies are inferred from the claim text.