Invention Grant
US09054485B1 Asymmetric edge compensation of both anode and cathode terminals of a vertical-cavity surface-emitting laser (VCSEL) diode
有权
垂直腔表面发射激光器(VCSEL)二极管的阳极和阴极端子的非对称边缘补偿
- Patent Title: Asymmetric edge compensation of both anode and cathode terminals of a vertical-cavity surface-emitting laser (VCSEL) diode
- Patent Title (中): 垂直腔表面发射激光器(VCSEL)二极管的阳极和阴极端子的非对称边缘补偿
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Application No.: US14488444Application Date: 2014-09-17
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Publication No.: US09054485B1Publication Date: 2015-06-09
- Inventor: Kwan Ting Ng
- Applicant: Hong Kong Applied Science & Technology Research Institute Company Limited
- Applicant Address: HK Hong Kong
- Assignee: Hong Kong Applied Science & Technology Research Institute Company, Ltd.
- Current Assignee: Hong Kong Applied Science & Technology Research Institute Company, Ltd.
- Current Assignee Address: HK Hong Kong
- Agency: gPatent LLC
- Agent Stuart T. Auvinen
- Main IPC: H01S3/13
- IPC: H01S3/13 ; H01S5/042 ; H01S5/183

Abstract:
A laser driver circuit compensates for non-linear behavior of Vertical-Cavity Surface-Emitting Laser (VCSEL) devices. A VCSEL has an internal parasitic capacitance that is charged while the VCSEL is on. When the VCSEL turns off, this internal parasitic capacitor discharges, keeping the VCSEL on longer, increasing the physical turn-off or fall time. The laser driver circuit compensates for the slower fall time by modulating both anode and cathode terminals of the VCSEL as the VCSEL is turned on and off. Both plates of the internal parasitic capacitor are discharged at turn off, cutting the parasitic discharge time in half. A cathode driver transistor modulates the cathode voltage while a source-follower transistor modulates the anode voltage. A modulating current may be switched using a current mirror structure. Multiple source-follower transistors may be selectable in parallel, with switches to select the total anode current, allowing for programmable compensation of the fall time.
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