Source Photonics (Chengdu) Company Limited

Xu Jiang

Yuanzhong Xu

Shuyuan Zhang

Yuan Song

A gain-variable trans-impedance amplifier (TIA) in optical device is disclosed. The TIA has an improved dynamic range for receiving electrical signals and is configured to convert current signals from an avalanche photodiode (APD) to voltage signals. A resistor element is between the input and output terminals of the TIA, wherein the resistance of the resistor element can regulate the resistance and/or impedance value of the TIA, and a switch determines or controls the resistance of the resistor element. When the power of an optical signal received by the APD is higher than a predetermined value, the resistance becomes smaller and the gain of the TIA becomes greater. When the power of the optical signal is lower than the predetermined value, the resistance becomes greater. The gain of the TIA is automatically adjusted on the basis of the intensity of received optical signals to obtain a greater dynamic operational range.

Transimpedance amplifier (TIA) having an enlarged dynamic range and optical devices using the same

A burst-mode laser control circuit and related methods thereof are disclosed. Using an APC loop with an additional burst-mode control circuit, and a switch in series with a diode and in parallel with the laser, a continuous-mode laser driver is enabled to operate in burst-mode by turning the switch on or off via external logic. Burst-mode control manages the switch, and a bandwidth-select circuit using a high or low logic level input, wherein the laser is disabled and the bandwidth-select circuit enters a fast-track mode when the external logic signal has a first level. The laser provides regular optical signals, and the bandwidth-select circuit enters a slow-track mode, thereby enabling the APC loop to operate normally, when the external logic signal has a second level. In addition to a low cost and simple implementation, the control circuit and method provide lasers with a fast response capability using one or more externally-controlled switch circuits to meet demands of PON systems for burst-mode ONUs.

Growing community of inventors

Chengdu, China

Xu Jiang