Micro Prism

A prism is a solid glass object given a specific geometric shape for the purpose of dispersing, deviating, rotating or displacing a beam of light. A micro prism, as the name suggests, is a very small version of an optical prism. Though there are many types of prisms, micro prisms are generally used to direct light in fiber optic communications, particularly in optical switches. Two types of micro prisms prove useful for these and other applications.

What Makes Micro Prisms Important?

Micro prisms provide an efficient way to change a beam of light’s directory inside an assembly or fiber optic device. When light goes through one of the faces on the prism, it’s refracted. Depending on the design of the prism, the light may be propelled in various angles before exiting the prism. The main purpose of a micro prism in fiber optics is to direct beams of light from one optical channel to another with high precision. Though micro prisms are small, they bring several big advantages to optics projects that employ them, including:

  • Precise deviation: The faces and angles of a prism are carefully engineered to meet precise calculations. When light enters the prism, it deviates the intended degree with a high level of consistency. The light will reach its destination uninterrupted more reliably than in systems using mirrors or multiple components, since these alternatives require perfect alignment to function.
  • High reflectivity: Micro prisms have high reflectivity, which helps minimize signal loss. At Shanghai Optics, for example, we make micro prisms with reflectivity greater than 95 percent per face for 1550 nm wavelengths.
  • Small size: The small size of micro prisms makes it possible to direct light with high accuracy while maintaining a relatively small device size. A micro prism takes up very little space inside an assembly or optic switch, which helps keep the technology compact and efficient.

All these benefits make a micro prism ideal for use as a circulator, interleaver or MEMS for fiber optic applications.

Micro Penta Prism

General Specifications
Material: BK7 Grade A optical glass, Corning Fused Silica 7980, JGS1, JGS2
90 degree Deviation Tolerance:Standard series: < 5 arc seconds
Precision series: <2 arc seconds
Flatness:Standard series: l/4 l at 632.8 nm
Precision series: l/8 l at 632.8 nm
Reflectivity: R > 95% per face from @1550 nm
Surface Quality: 40-20 scratch and dig
Working Wavelength: 1310, 1550, 1590 nm


Micro Right-Angle Prism

General Specifications
Dimension Tolerance: +0.0, -0.1 mm
Clear Aperture: > 90%
Flatness: l/2 l@632.8 nm
Surface Quality: 40-20 scratch and dig
Reflectivity: R>95% per face @ center wavelength
Working Wavelength: 1310, 1550, 1590 mm
Bevel: 0.1 mm to 0.2 mm


How Micro Prisms Are Produced

A micro prism’s performance is closely related to its design and manufacturing. In general, micro prisms are cut and ground out of optical glass, polished to meet precise specifications, given an outer coating and checked for defects. We make two types at Shanghai Optics coated or uncoated according to customer’s needs.

  • Penta micro prisms: The penta micro prism takes the shape of a pentagon, featuring seven faces and a stable light deviation of 90 degrees, regardless of where light enters the prism. We make our micro penta prisms using a variety of substrate materials, including BK7 Grade-A optical glass, Corning Fused Silica 7980, JGS1 and JGS2.
  • Right-angle micro prisms: Right-angle micro prisms take the shape of a right triangle, with two parallel triangular faces and three rectangular faces. These prisms can deviate light 90 degrees or 180 degrees, depending on which face the light initially enters. Our right-angle micro prisms have a bevel between 0.1 and 0.2 mm.

Though these prisms feature different shapes, they share many of the same physical properties, including reflectivity, surface quality and working wavelength. S.O. can make custom micro prisms using a number of different materials and coatings, including coatings for different UV, visible and IR wavelengths upon request.

Order Custom Micro Prisms From S.O.

Right-angle and penta micro prisms have a number of applications in fiber optics and beyond. Many of these applications require prisms that are tailored to unique specifications and fine-tuned for perfect performance. At Shanghai Optics, we manufacture micro prisms that meet both of these requirements. To ensure that our custom optical switch prisms meet your specifications, our production staff members follow ISO 9001 standards and use state-of-the-art metrology equipment to test performance. See how we can help with your current optics project by requesting a quote or contacting one of our friendly representatives for more information.


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