1x2 Multimode Fiber Optic Couplers
|Center Wavelength||850 nm|
|Wavelength Range||±40 nm|
|Ports||1 x 2|
|Operating Temperature||-40 to 85 °C (Unconnectorized Fiber)|
20 to 70 °C (Connectorized Fiber)
|Fiber Length||1.0 m|
|Damage Threshold||300 mW|
- 50:50, 90:10, or 99:1 Coupling Ratios
- Operating Wavelength: 850 ± 40 nm CW
- Ø50 µm or Ø62.5 µm Graded-Index Fibers
- Polarization Insensitive
- Stocked Unterminated or with FC/PC Connectors
- Alternative Terminations Available by Custom Order
- Maximum Average Power: 300 mW
- Contact Us for Custom Wavelength and Connector Options
Thorlabs offers an array of multimode 1x2 fiber couplers with Ø50 µm or Ø62.5 µm graded-index fibers operating at 850 ± 40 nm. These couplers are available with 50:50, 90:10, or 99:1 split ratios, either unterminated or terminated with FC/PC connectors. All splitters include Ø900 µm protective jacketing. Our multimode 1x2 couplers are fully bidirectional, allowing them to be used as couplers (combiners) or splitters. These multimode couplers offer low insertion loss and excellent environmental and mechanical stability, making them ideal solutions for combining and splitting signals in multimode fiber systems, such as monitoring optical signals with minimum loss. See the Chromatic Operation tab for information about using these couplers at other wavelengths.
Alternative Fiber Coupler Options
Thorlabs' multimode 1x2 couplers have a specified operating wavelength range of 850 ± 40 nm. However, the splitting ratio remains nearly constant over a much greater wavelength range, as shown in the plots below. Click here to download the coupling data shown below.
Explanation of Selected Specifications
This tab provides a brief explanation of how we determine several key specifications for our 1x2 couplers. The legs of the coupler are defined as shown in the diagram below.
Figure does not represent a specific coupling ratio (for demonstrational purposes only)
Excess loss in dB is determined by the ratio of the total output power to the total input power:
Pport1 is the input power at port 1 and Pport2+Pport3 is the total output power from Ports 2 and 3. All powers are expressed in mW.
Directivity (or Return Loss)
The return loss in fiber optic couplers is typically referred to as the directivity and can be calculated in units of dB using the following equation:
The fraction in the logarithm is the ratio of the input power at port 1 to any output power detected at port 2. This output is the result of some back reflection at the junction of the legs of the coupler and represents a loss in the total light output at ports 2 and 3. All powers are expressed in mW.
The insertion loss is determined by the ratio of the input power to the output power from one leg of the coupler. It can be generally written as
where the powers are in mW and the resulting insertion loss is in dB. To use a more specific example, the insertion loss of a signal from Port 1 to Port 2 may be written as
and the insertion loss from Port 1 to Port 3 as
Insertion loss is reversable, as discussed in the Reverse Operation tab.
Insertion loss can also be easily calculated with the power expressed in units of dBm. The power in mW is related to the power in dBm using the equation:
Then, the insertion loss in dB can be calculated as follows: