VCSEL (vertical cavity surface emitting laser) drive circuit

Abstract

The invention discloses a VCSEL (vertical cavity surface emitting laser) drive circuit used for supplying sufficient drive current and voltage to a VCSEL. The VCSEL drive circuit comprises an input buffer, a three-stage amplifier circuit, a current switch circuit and a bias current source circuit. The input buffer is used for impedance matching and adjustment of operating level of the circuit. The three-stage amplifier circuit is used for amplifying input signals, and providing sufficient gain to allow the current switch tube to obtain sufficient voltage swing in a given input signal amplitude range so as to push a current switch to effectively operate. A bias current source is DC-coupled to a cathode of the VCSEL through an off-chip inductor and provides proper direct bias current for the VCSEL, the effect of output alternating current on bias current can be reduced, and photoelectric conversion efficiency of the VCSEL is maximized. One differential output end of the current switch is connected with a power source, and the other differential output end of the current switch is connected to the cathode of the VCSEL. The magnitude of modulation current can be controlled by adjusting Vmod end voltage. The magnitude of direct bias current can also meet requirements of different VCSEL tube threshold currents by adjusting Vbias end voltage.

Description

technical field [0001] The invention is used in an optical transmitter of an optical communication system to realize the function of driving a vertical cavity surface emitting laser, and belongs to the technical field of optical communication devices. Background technique [0002] The International Technology Roadmap for Semiconductors (ITRS) points out that the growth rate of chip performance has far exceeded the growth rate of interconnect performance. The traditional electrical interconnection between chips has problems such as limited bandwidth, serious crosstalk, and high power consumption, and cannot meet the system application requirements of large-capacity data transmission, new-generation communication equipment, and high-performance computers. As a new interconnection method, optical interconnection has many incomparable advantages of electrical interconnection, such as high bandwidth, low power consumption, small delay, and anti-interference. At present, the band...

AI Technical Summary

Problems solved by technology

For the second circuit, each channel needs to use 4 on-chip inductors, and the number of 12-channel parallel channel inductors is as high as 48. Due to the large area of ​​on-chip inductors, considering the cost and chip area, this method is also not advisable.

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