CLADDING POWER STRIPPER

WHAT IS THE CLADDING POWER STRIPPER

The cladding power stripper (CPS) is an optical passive component commonly used in high-power fiber laser engines and fiber amplifiers. The main purpose of the CPS is to remove the residual pump light remaining in the fiber cladding and eliminate the laser light that is reflected from the processing components.

As shown in Figure 1, it depicts a schematic diagram of a cladding power stripper (CPS). The incoming signal from the left side of the diagram represents the forward signal, which corresponds to the pump light source. The incoming signal from the right side represents the backward signal, which indicating the reflected light. It can be observed that the cladding light in CPS, composed of both the forward and backward signals (represented by the gray and black arrows), can be effectively removed by the CPS. Simultaneously, the light in the core can pass through the CPS without encountering any obstruction. The term "Backward signal" refers to the laser light reflected from the surface of the processing parts. It is important to note that double-clad fibers (DCF) are commonly used in CPS, high-power fiber laser systems, and high-power fiber amplifiers.



THE TESTING PARAMETERS OF THE CLADDING POWER STRIPPER

The cladding power stripper has three important testing parameters that are described below:

  1. Signal insertion loss: The parameter refers to the power loss of the signal caused by the CPS. A higher signal insertion loss indicates a greater cost expenditure. The formula is defined as follows: Signal insertion loss (dB) = -10log10(P1⁄P0), where P0 represents the signal output power without the CPS, and P1 represents the signal output power with the CPS. It is typically expressed in decibels (dB).
  2. Cladding attenuation ：The parameter defines the amount of attenuation caused by the cladding power stripper. The formula is defined as follows: Cladding attenuation (dB) -10log10(P1 ⁄ P0), where Pin refers to the input cladding power and Pout refers to the output cladding optical power. It is typically expressed in decibels (dB). The parameter shows varying effects depending on the NA (Numerical Aperture) of the testing light source, with larger NA values resulting in higher cladding attenuation.
  3. Power handling capability: The parameter indicates the ability of the CPS to strip optical power. It represents the power stripping capability of the CPS for removing optical power. The power handling capacity is influenced by the heat dissipation performance of the CPS case. A casing with better heat dissipation will result in a higher power handling capability.



APPLICATION AND PRODUCT INTRODUCTION OF CLADDING POWER STRIPPERS (CPS):

The primary application of cladding power strippers is in high-power fiber laser engines and high-power fiber amplifiers. Figure 4 below illustrates the schematic structure of a high-power fiber laser engine, where the CPS is represented by the green-colored component.

The cladding power stripper itself does not generate heat, but the stripped light may generate heat upon interaction with the surrounding medium. Therefore, it is important to design the power handling capability of the CPS based on its packaging dimensions.