DFB Laser DC-Coupled Output Scheme for High-Temperature Headroom
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Solution Overview
Problem
Conventional DFB laser power supply configurations face challenges with insufficient headroom voltage at high temperatures, leading to reduced output power and eye opening margin, which affects high-speed data transmission quality.
Innovation Solution
A low-cost, high-performance DFB laser DC-coupled output power configuration scheme using an external or internal power configuration unit with a fixed voltage difference between the DFB laser and the optical transceiver integrated chip, employing a DC voltage source and a voltage difference generating component like resistors or Schottky diodes to optimize power supply voltages, ensuring a minimum voltage of 2.7V for the transmitting unit, thereby improving bandwidth and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional 3.3V power supply is used for both the transmitting unit and DFB laser, then the circuit is simple and cost-effective, but the headroom voltage becomes insufficient at high temperatures causing reduced output power and eye opening margin
Solution Approach 1:
The power supply system is segmented into two independent voltage domains: a 3.3V power supply for the DFB laser and a separately generated power supply for the transmitting unit. This segmentation allows each subsystem to operate at its optimal voltage level, preventing the headroom voltage insufficiency that occurs when a single 3.3V supply is used for both, while maintaining circuit simplicity through modular design.
Solution Approach 2:
The transmitting unit is provided with a dedicated power supply voltage that is locally optimized for its operating requirements, rather than sharing the generic 3.3V supply. This local quality approach ensures that the transmitting unit receives sufficient headroom voltage for high-speed switching at elevated temperatures, while the DFB laser continues to operate from the stable 3.3V supply.
2Reliability
If an external DC/DC boost module is added to increase the DFB laser power supply voltage, then the headroom voltage is sufficient for high-speed operation, but the device complexity and cost increase
Solution Approach 1:
Instead of boosting the DFB laser voltage to 4V as in conventional solutions, this invention inverts the approach by providing the transmitting unit with a higher voltage supply than the DFB laser. The DFB laser operates at the standard 3.3V, while the transmitting unit receives an optimized voltage that provides sufficient headroom for high-speed operation, eliminating the need for complex DC/DC boost modules.
Solution Approach 2:
The invention uses a voltage difference generating component that creates a scaled or offset copy of the reference voltage to generate the transmitting unit's power supply voltage. This copying approach provides a stable, temperature-compensated voltage supply without requiring complex DC/DC conversion circuits, thereby reducing device complexity while maintaining sufficient headroom voltage.
3Speed
If the power supply voltage for the transmitting unit is increased to provide sufficient headroom, then high-speed switching is maintained at high temperatures, but the power consumption increases
Solution Approach 1:
The invention optimizes the power consumption by carefully selecting and adjusting the voltage parameter for the transmitting unit. Rather than using a significantly higher voltage that would increase power consumption, the voltage is increased just enough to provide the necessary headroom for high-speed switching at high temperatures. The voltage difference generating component enables precise parameter control to achieve the minimum required voltage increase.
Solution Approach 2:
The invention applies partial action by providing voltage increase only where and when needed - specifically for the transmitting unit during high-temperature operation. The DFB laser continues to operate at the standard 3.3V without unnecessary voltage increase, thereby minimizing overall power consumption while ensuring the transmitting unit has sufficient headroom voltage for high-speed switching when required.
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
This configuration enhances the eye diagram performance under high temperature conditions, reduces power consumption, and lowers the overall cost by maintaining high-quality data transmission without the need for external boost modules.
Implementation Method 1
employing a DC voltage source and a voltage difference generating component like resistors or Schottky diodes to optimize power supply voltages
Implementation Method 2
a voltage difference generating component like resistors or Schottky diodes
Implementation Method 3
the laser driver (Laser Diode Driver) turns on or off the laser according to a logic value of the data stream and uses an optical fiber to transmit the optical signal
Data Source
AI summary
A DFB laser DC-coupled output power configuration scheme belongs to the field of laser drivers in optical communication integrated circuits. The present invention solves the existing problems in the conventional DFB laser power supply configuration scheme. The power configuration scheme of the present invention utilizes an external or internal power configuration unit to provide two electric DC power supplies with a fixed voltage difference for the transmitting unit TX of the DFB laser and the optical transceiver integrated chip, and at the same time optimizes the transmitting unit TX. The optimization scheme is that: the transistors in the transmitting unit TX are all low-voltage high-speed tubes, the transmitting unit TX includes a negative capacitance structure composed of capacitors C1 and C2, serving as an auxiliary structure for improving bandwidth. After optimization, the minimum voltage of the power supply voltage port TVCC of the transmitting unit TX is 2.7V.