Differential photoelectric receiver circuit

• US 6,707,023 B2
• Filed: 06/06/2001
• Issued: 03/16/2004
• Est. Priority Date: 06/13/2000
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Hartley, Lee F., Fong, Kai D.
• Primary Examiner(s): PYO, KEVIN K
• Application Number:
  US09/681,793
• Publication Number:
  US 20010050333A1
• Time in Patent Office: 1,014 Days
• Field of Search: 250/214.A, 250/214.LA, 250/214.AG, 250/214.C, 250/214.R, 330/59, 330/110, 330/308
• US Class Current: 250/214.00A
• CPC Class Codes: H03F 3/087 with IC amplifier blocks H03F3/085 takes precedence
• CPC Class Codes: H03K 17/785 controlling field-effect transistor switches

Abstract

A photoelectric receiver circuit for converting an optical signal to an electrical signal, includes first and second transimpedance amplifiers, a photodiode having a first end connected to an inverting input of the first transimpedance amplifier and a second end connected to an inverting input of the second transimpedance amplifier, and a differential amplifier having inputs AC coupled to outputs of the first and second transimpedance amplifiers. Such that when higher and lower voltages are respectively applied to the non-inverting inputs of the first and second transimpedance amplifiers, a substantially constant bias voltage is maintained on the photodiode.

Claims

1. A photoelectric receiver circuit for converting an optical signal to an electrical signal, comprising:

first and second transimpedance amplifiers,

a photodiode having a first end connected to an inverting input of the first transimpedance amplifier and a second end connected to an inverting input of the second transimpedance amplifier,

a differential amplifier having inputs, AC coupled, to outputs of the first and second transimpedance amplifiers, and

wherein when higher and lower voltages are respectively applied to the non-inverting inputs of the first and second transimpedance amplifiers, a substantially constant bias voltage is maintained on the photodiode.

2. The photoelectric receiver circuit of claim 1 in which the transimpedance amplifiers each comprise an operational amplifier having an inverting input, a non-inverting input and an output, and a feedback resistor connected between the inverting input and the output.

3. The photoelectric receiver circuit of claim 2 comprising a DC current source supplyinq a DC current to the inverting input of each operational amplifier.

4. The photoelectric receiver circuit of claim 2 wherein at least one of the feedback resistors is a variable resistor.

5. The photoelectric receiver circuit of claim 4 wherein both of the feedback resistors are variable resistors.

6. The photoelectric receiver circuit of claim 3 wherein the level of DC current applied to each inverting input is controlled by the output of the respective transimpedance amplifiers through a low pass filter.

7. An optical transceiver comprising a photoelectric receiver circuit for converting an optical signal to an electrical signal, the photoelectric receiver circuit comprising:

first and second transimpedance amplifiers,

a photodiode having a first end connected to an inverting input of the first transimpedance amplifier and a second end connected to an inverting input of the second transimpedance amplifier, and

a differential amplifier having inputs, AC coupled, to outputs of the first and second transimpedance amplifiers,

two voltages for applying a bias voltage to the photodiode,

wherein when higher and lower voltages are respectively applied to the non-inverting inputs of the first and second transimpedance amplifiers, a substantially constant bias voltage is maintained on the photodiode.

8. The optical transceiver of claim 7 in which the transimpedance amplifiers each comprise an operational amplifier having an inverting input, a non-inverting input and an output, and a feedback resistor connected between the inverting input and the output.

9. The optical transceiver of claim 8 comprising a DC current source supplying a DC current to the inverting input of each operational amplifier.

10. The optical transceiver of claim 8 wherein at least one of the feedback resistors is a variable resistor.

11. The optical transceiver of claim 10 wherein both of the feedback resistors are variable resistors.

12. The optical transceiver of claim 9 wherein the level of DC current applied to each inverting input is controlled by the output of the respective transimpedance amplifiers through a low pass filter.