Semiconductor Laser Driver Layout for Low-Inductance Waveforms
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Solution Overview
Problem
The integration of a laser diode array and a driver IC in existing optical modules results in high wiring inductance, leading to distorted drive waveforms, particularly in ToF systems operating at high frequencies.
Innovation Solution
A semiconductor laser driving apparatus with a substrate incorporating a laser driver and a semiconductor laser, connected via wiring with 0.5 nanohenries or less, and a shield to suppress electromagnetic interference, reducing leakage and improving signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the laser diode array and driver IC are integrated and electrically connected using multiple wires in a conventional optical module, then the integration is achieved, but the wiring inductance becomes large causing drive waveform distortion
Solution Approach 1:
The patent merges the driver IC and laser diode array into a single integrated optical module housed in one case, eliminating the need for external wire connections. This consolidation reduces wiring inductance to minimal levels, preventing drive waveform distortion while maintaining functional integration of both components
Solution Approach 2:
The patent extracts and eliminates the problematic external wiring connections between the driver IC and laser diode array. By integrating both components within the same housing and using internal trace connections instead of external wires, the harmful inductance is removed while preserving the necessary electrical connectivity
2Power
If multiple wires are used to connect the driver IC and laser diode array, then electrical connection is established, but wiring inductance increases leading to signal distortion at high frequencies
Solution Approach 1:
The patent replaces the mechanical wire-based electrical connection system with an integrated circuit board trace connection system. This substitution eliminates the high inductance characteristic of external wires while maintaining electrical connectivity, thereby preserving signal integrity at high frequencies up to hundreds of megahertz
3Device complexity
If conventional wiring methods are used without shielding, then the structure is simple, but electromagnetic waves leak to the outside causing interference
Solution Approach 1:
The patent employs a shield structure in the form of a thin conductive film or shell that covers the optical module housing. This shield effectively blocks electromagnetic waves from leaking outward while maintaining the compact and relatively simple overall structure of the integrated module
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces wiring inductance and prevents electromagnetic interference, stabilizing the drive waveform and enhancing signal quality in high-frequency operations.
Implementation Method 1
a shield that suppresses flow of electromagnetic waves to/from an outside for at least one of the semiconductor laser and the laser driver
Data Source
AI summary
To reduce the wiring inductance when establishing electrical connection between a semiconductor laser and a laser driver in a semiconductor laser driving apparatus. A semiconductor laser driving apparatus includes a substrate, a laser driver, and a semiconductor laser. The substrate incorporates the laser driver. The semiconductor laser is mounted on one surface of the substrate. Connection wiring electrically connects the laser driver and the semiconductor laser to each other with a wiring inductance of 0.5 nanohenries or less. A shield suppresses flow of electromagnetic waves to/from an outside of the semiconductor laser driving apparatus for at least one of the semiconductor laser and the laser driver.