Apparatus and methods for noise-feedback controlled optical systems
First Claim
1. An apparatus operable in an environment exhibiting significant variation in temperature, the apparatus comprising:
- an optical signal transmitter; and
an optical signal receiver for receiving an optical signal from the transmitter, the receiver including a photodiode for converting the optical signal to an electrical signal;
the receiver further including a feedback loop for monitoring the electrical signal outputted by the photodiode, computing a ratio of noise energy for high and low signal in the monitored signal, using the ratio to determine when temperature-induced breakdown is imminent, and adjusting gain of the photodiode as a function of the ratio to prevent breakdown;
wherein the feedback loop adjusts the gain without using measured temperature of the environment.
1 Assignment
0 Petitions
Accused Products
Abstract
Apparatus and methods for noise-feedback controlled optical systems are disclosed. In one aspect, an apparatus includes a receiver adapted to receive an optical signal and to convert the optical signal to a corresponding electrical signal, and a control circuit coupled to the receiver. The control circuit includes a monitoring component adapted to monitor a noise level of at least a portion of the electrical signal and to adjust a gain of the receiver based on the noise level. In an alternate aspect, an optical system includes a transmitter, a receiver, and a monitoring component adapted to monitor a noise level of at least a portion of the electrical signal and to adjust at least one of an amplification of the transmitter and a gain of the receiver based on the noise level.
-
Citations
25 Claims
-
1. An apparatus operable in an environment exhibiting significant variation in temperature, the apparatus comprising:
-
an optical signal transmitter; and an optical signal receiver for receiving an optical signal from the transmitter, the receiver including a photodiode for converting the optical signal to an electrical signal; the receiver further including a feedback loop for monitoring the electrical signal outputted by the photodiode, computing a ratio of noise energy for high and low signal in the monitored signal, using the ratio to determine when temperature-induced breakdown is imminent, and adjusting gain of the photodiode as a function of the ratio to prevent breakdown; wherein the feedback loop adjusts the gain without using measured temperature of the environment. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. An optical system, comprising:
-
a transmitter configured to transmit an optical signal; a receiver including an avalanche photodiode configured to receive the optical signal and to output an electrical signal; and a feedback loop for increasing dynamic range of the receiver when an optical signal is high and preventing temperature-induced breakdown of the avalanche photodiode, the feedback loop monitoring a noise level of at least a portion of the electrical signal including determining a presence or absence of the optical signal at the receiver, computing at least one of a high state means and a low state means of the electrical signal, computing an average noise energy for the high-state A, computing an average noise energy for the low-state −
A, and computing a ratio of the average noise energies for the high- and low-states A, −
A, andpreventing temperature-induced breakdown, including using the ratio as an indicator of temperature-induced breakdown, and reducing at least one of an optical amplification of the transmitter and a gain of the receiver when the ratio is greater than a predetermined threshold, the threshold indicating that breakdown of the photodiode is imminent. - View Dependent Claims (12, 13)
-
-
14. An aircraft comprising:
-
a fuselage; a propulsion system operatively coupled to the fuselage; and an optical system configured to transmit signals, the optical system including; a transmitter configured to transmit an optical signal, the transmitter including an optical amplifier; a receiver configured to receive the optical signal and to output an electrical signal; and a monitoring component to provide a feedback loop to increase a dynamic range of the receiver when an optical signal is high without measuring a temperature of the surrounding environment of the receiver, the monitoring component to; monitor a noise level of at least a portion of the electrical signal, and reduce at least one of an amplification of the transmitter and a gain of the receiver when a ratio of an average energy of a high-state A of the electrical signal and an average energy of a low-state A of the electrical signal is greater than a predetermined threshold, the threshold value being at a point where a breakdown voltage of the receiver is eminent. - View Dependent Claims (15, 16, 17, 18, 19)
-
-
20. A method comprising:
-
receiving an optical signal in an environment exhibiting significant variation in temperature; using a photodiode to convert the optical signal to a corresponding electrical signal; monitoring the electrical signal outputted by the photodiode; computing a ratio of noise energy for high and low signal in the monitored signal; using the ratio as an indicator of imminent temperature-induced breakdown of the photodiode; and preventing breakdown of the photodiode by adjusting gain of the photodiode without monitoring the temperature of surrounding environment when the ratio indicates that temperature-induced breakdown is imminent. - View Dependent Claims (21, 22, 23, 24, 25)
-
Specification