Avalanche photodiode controller circuit for fiber optics transceiver

• US 20030210917A1
• Filed: 03/18/2002
• Published: 11/13/2003
• Est. Priority Date: 02/12/2002
• Status: Active Grant

• Current Assignee: II-VI Delaware, Inc. (Coherent Corp.)
• Original Assignee: Finisar Corporation (II-VI Incorporated)
• Inventors: Weber, Andreas, Stewart, James, Hofmeister, Rudolf J., Douma, Darin James, Ho, Anthony, Hosking, Stephen G., Price, Jeffrey Bryant
• Granted Patent: US 7,155,133 B2
• Time in Patent Office: Days
• US Class Current: 398/209
• CPC Class Codes: H04B 10/6911 Photodiode bias control, e.g. for compensating temperature variations
• CPC Class Codes: H04B 10/6931 Automatic gain control of the preamplifier

Abstract

A controller for controlling the reverse-bias voltage of an avalanche photodiode in a transceiver or receiver. The controller includes memory for storing information related to the avalanche photodiode, and analog to digital conversion circuitry for receiving an analog signal corresponding to the temperature of the avalanche photodiode, converting the received analog signal into a digital value, and storing the digital value in a predefined location within the memory. Control circuitry in the controller controls the operation of the avalanche photodiode in accordance with the digital value corresponding to the temperature of the avalanche photodiode and a temperature lookup table stored in the memory. A serial interface is provided to enable a host device to read from and write to locations within the memory. The invention is also implemented as a method for controlling the reverse-bias voltage of an avalanche photodiode in a transceiver or receiver and a method for calibrating a transceiver or receiver having an avalanche photodiode.

Claims

1. An optoelectronic assembly, selected from one of an optoelectronic transceiver and an optoelectronic receiver, comprising:

a housing;

an avalanche photodiode disposed within the housing;

a power supply disposed within the housing to supply a reverse-bias voltage to the avalanche photodiode; and

an integrated circuit disposed within the housing and configured to output a control signal to the power supply, wherein the control signal controls the reverse-bias voltage supplied to the avalanche photodiode.

2. The optoelectronic assembly of claim 1, further comprising a temperature sensor disposed within the housing to measure temperature of the avalanche photodiode, wherein the integrated circuit is configured to process a temperature signal received from the temperature sensor.

3. The optoelectronic assembly of claim 1, wherein the integrated circuit comprises:

memory, including one or more nonvolatile memory arrays for storing information related to the avalanche photodiode;

an interface for reading from and writing to locations within the memory in accordance with commands from a host device;

analog to digital conversion circuitry for receiving an analog signal, converting the received analog signal into a digital value, and storing the digital value in a predefined location within the memory;

logic configured to determine a control value associated with a reverse-bias voltage for the avalanche photodiode in accordance with one or more digital values stored in the memory; and

digital to analog circuitry configured to convert the control value to a control signal to control the reverse-bias voltage supplied to the avalanche photodiode.

4. The optoelectronic assembly of claim 1, wherein the integrated circuit comprises:

memory, including one or more nonvolatile memory arrays for storing information related to the avalanche photodiode;

an interface for reading from and writing to locations within the memory in accordance with commands from a host device;

a temperature sensor to measure temperature;

analog to digital conversion circuitry for receiving an analog signal from the temperature sensor, converting the received analog signal into a digital value, and storing the digital value in a predefined location within the memory;

logic configured to determine a control value associated with a reverse-bias voltage for the avalanche photodiode in accordance with one or more digital values stored in the memory; and

digital to analog circuitry configured to convert the control value to a control signal to control the reverse-bias voltage supplied to the avalanche photodiode.

5. The optoelectronic assembly of claim 1, further comprising a temperature sensor disposed within the housing to measure temperature of the avalanche photodiode, wherein the integrated circuit comprises:

memory, including one or more memory arrays for storing information related to the avalanche photodiode;

an interface for reading from and writing to locations within the memory in accordance with commands from a host device;

analog to digital conversion circuitry for receiving an analog signal from the temperature sensor, converting the received analog signal into a digital value, and storing the digital value in a predefined location within the memory;

logic configured to determine a control value associated with a reverse-bias voltage for the avalanche photodiode in accordance with one or more digital values stored in the memory; and

digital to analog circuitry configured to convert the control value to a control signal to control the reverse-bias voltage supplied to the avalanche photodiode.

6. The optoelectronic assembly of claim 5, wherein the memory includes a lookup table having a plurality of entries, and the integrated circuit is configured to determine the control value based in part on one of the plurality of entries in the lookup table.

7. The optoelectronic assembly of claim 5, wherein the integrated circuit is configured to determine the control value based in part on digital values corresponding to an analog signal received from the temperature sensor.

8. An optoelectronic assembly, selected from one of an optoelectronic transceiver and an optoelectronic receiver, comprising:

a housing;

an avalanche photodiode disposed within the housing;

a power supply disposed within the housing to supply a reverse-bias voltage to the avalanche photodiode; and

an integrated circuit disposed within the housing, wherein the integrated circuit stores at least one digital value associated with the avalanche photodiode for controlling the reverse-bias voltage supplied to the avalanche photodiode.

9. The optoelectronic assembly of claim 8, further comprising a temperature sensor disposed within the housing to measure temperature of the avalanche photodiode, wherein the integrated circuit is configured to process a temperature signal received from the temperature sensor.

10. A single-chip integrated circuit for controlling an avalanche photodiode, comprising:

memory, including one or more memory arrays for storing information related to the avalanche photodiode;

an interface for reading from and writing to locations within the memory in accordance with commands from a host device; and

control circuitry configured to generate a control signal to control a reverse-bias voltage of the avalanche photodiode in accordance with one or more digital values stored in the memory.

11. The single-chip integrated circuit of claim 10, further including

a temperature sensor for generating a temperature signal corresponding to a temperature of the avalanche photodiode;

and

analog to digital conversion circuitry configured to receive the temperature signal, convert the temperature signal into a digital temperature value and store the digital temperature value in a predefined temperature location within the memory.

12. A method for controlling an optoelectronic assembly, selected from one of an optoelectronic transceiver and an optoelectronic receiver, the optoelectronic assembly having an avalanche photodiode, the method comprising:

receiving an analog signal corresponding to a temperature of the avalanche photodiode;

converting the analog signal into a digital value;

storing the digital value in a predefined location in one or more of the memory arrays; and

generating a control signal to control a reverse-bias voltage of the avalanche photodiode in accordance with one or more digital values stored in memory.

13. A method for calibrating an optoelectronic assembly, selected from one of an optoelectronic transceiver and an optoelectronic receiver, the optoelectronic assembly having an avalanche photodiode and an integrated circuit, the method comprising determining an optimal reverse-bias voltage for the avalanche photodiode at a specified temperature by:

measuring a bit error rate for the avalanche photodiode wherein a reverse-bias voltage is set to a predetermined starting voltage;

adjusting the reverse-bias voltage until the bit error rate is minimized;

storing digital values corresponding to the adjusted reverse-bias voltage and the specified temperature in a memory in the integrated circuit within the optoelectronic assembly.

14. The method of claim 13, further comprising changing the specified temperature to a plurality of designated temperatures and determining a plurality of optimal reverse-bias voltages for the avalanche photodiode, each optimal reverse-bias voltage corresponding to one of the plurality of designated temperatures.

15. A method for calibrating an optoelectronic assembly, selected from one of an optoelectronic transceiver and an optoelectronic receiver, the optoelectronic assembly having an avalanche photodiode and an integrated circuit, the method comprising determining an optimal reverse-bias voltage for the avalanche photodiode at a specified temperature by:

increasing a reverse-bias voltage of the avalanche photodiode from a predetermined starting voltage until an avalanche breakdown occurs;

reducing the reverse-bias voltage from the reverse bias voltage at which the avalanche breakdown occurred by a predetermined offset voltage;

storing digital values corresponding to the reduced reverse-bias voltage and the specified temperature in a memory in the integrated circuit within the optoelectronic assembly.

16. The method of claim 15, further comprising changing the specified temperature to a plurality of designated temperatures and determining a plurality of optimal reverse-bias voltages for the avalanche photodiode, each optimal reverse-bias voltage corresponding to one of the plurality of designated temperatures.