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ONET1101L: The additional power consumption issue caused by impedance matching of onet1101L

Adah-Zhao
Prodigy 70 points
Part Number: ONET1101L

Tool/software:

onet1101L,The chip output is stated on the datasheet as having a 25 ohm impedance, which means that an impedance matching network needs to be used for impedance matching in the output section. After reviewing the information and actual measurements, adding low resistance resistors for matching will increase additional power consumption. This means that the current I supply to the laser diode will be lost by the resistor.Does this mean that the chip's nominal 100mA bias current and 85mA modulation current cannot achieve full power when actually used in a load?

But impedance matching of the load is necessary. According to actual measurements, with a current of 70mA, only about 45mA is effectively used. Is there any way to avoid such a large loss? This has a serious impact on performance

  • 0
    TI__Guru* 93670 points

    Hi Adah,

    Figure 13 and 10 show modulation and bias current versus register setting. Device is able to deliver 80mA and 100mA bias current respectively.

    1). Note figures 19 and 20 of the data sheet. Frerrite beads are attached at the output MOD+/-. This means modulation current is dumped into the output structure of the device.

    2). There is AC coupling Cap so there is no DC current path into the laser diode.

    Regards, Nasser