公开(公告)号：US11843418B2

公开(公告)日：2023-12-12

申请号：US17476969

申请日：2021-09-16

Applicant: Cisco Technology, Inc.

Inventor： Daniel Micusik ,  Sachidanandam Sundarraju ,  Jan Sundermeyer ,  Juergen Hauenschild

IPC: H04B10/69

CPC classification number: H04B10/69

Abstract: A method and apparatus that cancels or reduces DC offset in a fully-differential optical receiver. The method includes receiving differential optical signals, converting, with photodetectors, the differential optical signals to differential current signals representative of the differential optical signals, converting, using a transimpedance amplifier, the differential current signals to differential intermediate voltage signals, amplifying, using a main amplifier, the differential intermediate voltage signals to generate differential output voltage signals, and cancelling a DC component of the differential output voltage signals using a fully differential DC cancellation circuit. Output offset may also be cancelled or reduced using digital control.

公开(公告)号：US20230084591A1

公开(公告)日：2023-03-16

申请号：US17476969

申请日：2021-09-16

Applicant: Cisco Technology, Inc.

Inventor： Daniel Micusik ,  Sachidanandam Sundarraju ,  Jan Sundermeyer ,  Juergen Hauenschild

IPC: H04B10/69

Abstract: A method and apparatus that cancels or reduces DC offset in a fully-differential optical receiver. The method includes receiving differential optical signals, converting, with photodetectors, the differential optical signals to differential current signals representative of the differential optical signals, converting, using a transimpedance amplifier, the differential current signals to differential intermediate voltage signals, amplifying, using a main amplifier, the differential intermediate voltage signals to generate differential output voltage signals, and cancelling a DC component of the differential output voltage signals using a fully differential DC cancellation circuit. Output offset may also be cancelled or reduced using digital control.

公开(公告)号：US12170525B2

公开(公告)日：2024-12-17

申请号：US17993163

申请日：2022-11-23

Applicant: Cisco Technology, Inc.

Inventor： Juergen Hauenschild ,  Sachidanandam Sundarraju ,  Jan Louis Sundermeyer

IPC: H03M1/66 ,  H01S5/183 ,  H01S5/50

Abstract: An interface circuit that interfaces a digital-to-analog converter (DAC) to a vertical-cavity surface emitting laser. The apparatus includes a first cascode amplifier that receives as input positive and negative differential outputs of the DAC and provides a positive amplified output and a negative amplified output, and a second cascode amplifier having a positive input and a negative input. The positive input of the second cascode amplifier being coupled to the positive amplified output of the first cascode amplifier. The second cascode amplifier is configured to generate a positive amplified current and a negative amplified current at a negative amplified output. The positive amplified current and the negative amplified current are combined and a resulting output current is provided as input to an anode of the laser. A transformer is coupled between the negative amplified output of the first cascode amplifier and the negative input of the second cascode amplifier.

公开(公告)号：US20240171194A1

公开(公告)日：2024-05-23

申请号：US17993163

申请日：2022-11-23

Applicant: Cisco Technology, Inc.

Inventor： Juergen Hauenschild ,  Sachidanandam Sundarraju ,  Jan Louis Sundermeyer

IPC: H03M1/66 ,  H01S5/183 ,  H01S5/50

CPC classification number: H03M1/66 ,  H01S5/183 ,  H01S5/5027

Abstract: An interface circuit that interfaces a digital-to-analog converter (DAC) to a vertical-cavity surface emitting laser. The apparatus includes a first cascode amplifier that receives as input positive and negative differential outputs of the DAC and provides a positive amplified output and a negative amplified output, and a second cascode amplifier having a positive input and a negative input. The positive input of the second cascode amplifier being coupled to the positive amplified output of the first cascode amplifier. The second cascode amplifier is configured to generate a positive amplified current and a negative amplified current at a negative amplified output. The positive amplified current and the negative amplified current are combined and a resulting output current is provided as input to an anode of the laser. A transformer is coupled between the negative amplified output of the first cascode amplifier and the negative input of the second cascode amplifier.