PPLN Chip Plus
With its technology core in nonlinear grating fabrication (i.e. PPLN Chips) for nonlinear frequency mixing, HC Photonics extends its core to linear grating fabrication (i.e. VPH/FBG) for linear wavelength management. Those linear grating components could provide complementary functions (such as selected wavelength reflection, locking, filtering, coupling, pulse stretch, pulse compression, sensing, etc.) to PPLN nonlinear grating components, thus we also categorize them as PPLN Chips Plus in our product family.
Volume Phase Holographic (VPH)
Fiber Bragg Grating (FBG)
Volume Phase Holographic (VPH) Gratings
Volume Phase Holographic Gratings diffract light through the refractive index modulations within a thin layer of material. They are designed to work at different wavelengths by adjusting the thickness and the index modulation of the medium and are commonly used as transmission gratings. Our VPH delivers high peak diffraction efficiency (> 90% typical) to increase optical signal for most applications.
Key features
• Gratings for spectrometer, tunable filter, pulse stretch/compression, etc.
• Tunable center wavelength
• High efficiency and smooth efficiency variation with wavelength
• Reduced polarization sensitivity
• Reduced surface reflection
• Easy cleaning & handling
• Customization available
VPH Manufacturing Process
VPHs are recorded by means of two beams interference. It creates a fringe pattern (ultraviolet light) to which the emulsion layer is exposed. VPHs are then formed by the development of emulsions.
Robust and Easy to Clean
VPHs are properly sealed and protected by glass plates. Therefore, our VPHs can be handled and cleaned like any other glass optical component. This is very different from ruled gratings which can be easily damaged by moisture, fingerprints, aerosols, or the slightest contact with any abrasive material.
Fiber Bragg Grating (FBG)
A Fiber Bragg Grating (FBG) is a periodic refractive index variation of the fiber core along the fiber length, which is formed by exposure of the core to an intense optical interference pattern. This refractive index variation makes a FBG act like a dielectric mirror that reflects certain wavelengths and transmits others.
Key features
• Standard off-the-shelf items for your “quick plug-in” applications
• PMF (Polarization-Maintaining Fibers) FBG
• Uniform/Chirped FBG available
• Customization available
FBG Manufacturing Process
FBGs are manufactured by exposing the core of a specially prepared optical fiber to a fringe pattern of ultraviolet light, generated by two beams interference.
Our grating writing technology utilizes a phase mask to generate two‐beam interference to create the fringe pattern. Various phase masks and aperture plates are available for FBG customization.FBG Customization
By actively controlling the period of the fringe pattern, fundamental grating characteristics such as
- Center wavelength
Bandwidth/Wavelength range
- Reflectivity
can be tuned to fit specific applications need
Matched Fiber Bragg Grating pair (Fiber Bragg Grating mirrors)
Two separate FBGs can be made with matched center wavelength for your specific applications (ex. fiber laser).
FBG Recoating and Packaging
Various types of FBG recoating and packaging are available
- Recoating: Low index polymer
- Packaging: Standard steel or aluminum package (mechanical shock protection) for standard package size and mini-packaging size are available
- Customization is welcome upon request
Reference specifications (examples)
