What is a directional coupler in photonics?
The directional coupler is one of the fundamental building blocks in photonics circuits. It couples light from one port to another and is frequently used as a power splitting and combining component in devices like ring resonators, Mach-Zehnder interferometers and other filters.
What is a directional coupler used for?
Directional couplers are an important type of signal processing device. Their basic function is to sample RF signals at a predetermined degree of coupling, with high isolation between the signal ports and the sampled ports — which supports analysis, measurement and processing for many applications.
What are the types of directional couplers?
Directional couplers
- Coupled transmission lines.
- Branch-line coupler.
- Lange coupler.
- Wilkinson power divider.
- Hybrid coupler.
- Hybrid ring coupler.
- Multiple output dividers.
- Waveguide branch-line coupler.
What is the material of directional coupler?
Two embedded optical waveguides in close proximity form a directional coupler. The cladding material is GaAs and the core material is ion-implanted GaAs. The waveguide is excited by the two first supermodes of the waveguide structure – the symmetric and antisymmetric modes.
Is directional coupler reciprocal?
A directional coupler is a reciprocal network where in theory all ports are ideally matched and the circuit itself is theoretically lossless [7]. Directional couplers can be designed using microstrip, stripline, coax, or waveguide technology.
What is directional coupler in RF?
A directional coupler is a 4-port device that is used to sample a small amount of input signal power for measurement purposes. When an input signal travels from port 1 to port 2, a part of this signal is coupled to port 3.
What is forward directional coupler?
A Directional coupler is a device that samples a small amount of Microwave power for measurement purposes. The power measurements include incident power, reflected power, VSWR values, etc. Directional Coupler is a 4-port waveguide junction consisting of a primary main waveguide and a secondary auxiliary waveguide.
How many holes can be there in a directional coupler?
A two-hole directional coupler is designed to meet the ideal requirement of directional coupler, which is to avoid back power. Some of the power while travelling between Port 1 and Port 2, escapes through the holes 1 and 2. The magnitude of the power depends upon the dimensions of the holes.
What is the difference between coupler and combiner?
Coupler: It is to distribute the input signal proportionally to multiple outputs. Combiner: combines multiple input signals into one input.
How does coupling occur in directional coupler?
Directional couplers are four-port circuits where one port is isolated from the input port. Directional couplers generally use the distributed properties of microwave circuits. The coupling process generally occurs within a quarter-wavelength or multiple quarter-wavelength portions of the device.
What are the applications of a directiondirectional coupler?
Directional couplers are also useful since the power reflected from the probe can be continuously monitored, thereby allowing tuning and monitoring for breakdown, which is sometimes important in high-power experiments. Govind P. Agrawal, in Applications of Nonlinear Fiber Optics (Third Edition), 2021
How do you define coupling directivity and isolations?
Define coupling, directivity, and isolations as the following ratios: FIGURE 2.38. Directional coupler. Coupling denotes the fraction of input power that is coupled to port 4 from port 1. Depending on the application, the coupling factor can be as high as 30 dB.
What are the different types of couplers used in guided wave devices?
Section 2.4 extends the discussion to asymmetric, active, and birefringent couplers. Fibers with multiple cores are considered in Section 2.5. Directional couplers are the most important and effective circuits in single-mode guided-wave devices.
How high can the coupling factor of a wireless speaker be?
Depending on the application, the coupling factor can be as high as 30 dB. Directivity and isolation both signify the device’s capability to isolate forward and backward waves (leakage). It is desirable to maximize the directivity of the device as much as possible.