公开(公告)号：US20210250099A1

公开(公告)日：2021-08-12

申请号：US17135593

申请日：2020-12-28

Applicant: Fujitsu Optical Components Limited

Inventor： Tetsuji YAMABANA ,  Tsuyoshi MORISHITA

IPC: H04B10/50 ,  H04B10/564 ,  H04B10/556

Abstract: Controller and control method are provided. In particular, a controller is disclosed as being configured to hold intensities of a monitor signal, which changes according to an output from a region in a device, before and after altering a state of a portion in the region and control the state of the portion based on a difference between the held intensities.

公开(公告)号：US20220404678A1

公开(公告)日：2022-12-22

申请号：US17742812

申请日：2022-05-12

Applicant: Fujitsu Optical Components Limited

Inventor： Tetsuji YAMABANA

IPC: G02F1/21 ,  G02F1/025 ,  G02F1/225 ,  G02B6/293

Abstract: In an optical transmitter having an electro-optic modulator with first child MZI and a second child MZI nested to form a parent MZI, and a processor that controls the bias voltages of electro-optic modulator. In the first section of a control loop, the processor simultaneously superimposes different dither signals onto the first bias voltage of the first child MZI and 1.0 the second bias voltage of the second child MZI, and extracts the first phase error information for the first child MZI and the first-round third phase error for the parent MZI from a first monitoring result. In the second section of the control loop, the processor simultaneously superimposes different dither signals onto the first and second bias voltages, and extracts the second phase error information for the second child MZI and the second-round third phase error for the parent MZI from a second monitoring result.

公开(公告)号：US20230102995A1

公开(公告)日：2023-03-30

申请号：US17877259

申请日：2022-07-29

Applicant: Fujitsu Optical Components Limited

Inventor： Tetsuji YAMABANA ,  Koji Terada

IPC: H04B10/564 ,  H04B10/40 ,  H04B10/516 ,  H04B10/61

Abstract: An optical coherent transceiver includes a transmitter and a receiver that share laser light. The transmitter includes a pair of parent MZIs in a modulator, which are parent MZIs configured to perform quadrature modulation on the laser light according to a bias voltage, and two pairs of child MZIs in the modulator, which are child MZIs configured to perform phase modulation on the laser light according to the bias voltage. The transmitter includes a control circuit configured to control the bias voltage to be applied to the parent MZIs and the child MZIs. The control circuit is configured to, when turning light output of the transmitter off, with input of a data signal being set off, control the bias voltage such that a phase difference between the parent MZIs is around 90 degrees and a phase difference between the child MZIs in each of the pairs is 180 degrees.