Jingcheng Zhang

US Patent:

8051665, Nov 8, 2011

Filed:

Dec 12, 2007

Appl. No.:

11/955292

Inventors:

Ziv Lipkin - Cupertino CA, US
Jingcheng Zhang - Saratoga CA, US

Assignee:

Finisar Corporation - Sunnyvale CA

International Classification:

F25B 21/02

US Classification:

62 37, 62 32

Abstract:

A temperature control system is provided for efficiently controlling the temperature of an optical transmitter such as a laser diode. The temperature control system of the present invention reduces power consumption and achieves a higher efficiency by employing a voltage controller and a high-efficiency DC-DC step-down converter between the TEC controller, which drives the thermoelectric cooler, and the microcontroller, which governs the optical transmitter operation. The voltage controller converts an analog voltage command signal into a current-based command signal, which is then sent to the DC-DC step-down converter. The DC-DC converter produces a stepped-down voltage which it supplies to the TEC controller. The TEC controller receives the stepped-down voltage input from the DC-DC converter and outputs a corresponding current signal to the thermoelectric cooler. Because the current signal output by the TEC controller is proportional to the voltage signal it receives from the DC-DC converter, the current signal is reduced in magnitude.

US Patent:

60552522, Apr 25, 2000

Filed:

Sep 10, 1998

Appl. No.:

9/151056

Inventors:

Jingcheng Zhang - San Jose CA

Assignee:

Photonic Solutions, Inc. - San Jose CA

International Classification:

H01S 304

US Classification:

372 34

Abstract:

Techniques for controlling the operation of a laser diode to maintain optimum operating characteristics (i. e. , fairly constant output power and extinction ratio) despite the fact that the threshold current and slope efficiency vary greatly over a the desired range of operating temperature. A laser driving circuit includes a bias current generator, a temperature-dependent modulation current generator, and a switching element for switching the modulation current on and off in accordance with a desired input pattern. The modulation current is caused to vary with temperature in a manner that compensates for the fact that the laser diode's slope efficiency varies with temperature.