Reflectivity and Phase (GDD) control
· A wavelength range 600 nm to 1000 nm is
· Silver mirrors have a naturally flat phase at
600 nm to 1000 nm and work reasonably well.
The down-side is the relatively high 3% loss
…nm/˚C Bragg Mirror Reflectivity 5 10-98 >99.9 % Reflectivity Tolerance 1 -5 — +5 % Grating Slant Angle — Features & Benefits
* Increases spectral brightness of lasers
* Reduces thermal dependence of lasers
* Reduces unwanted spectral components
* Ultra-narrow bandwidth
* Low loss
* Highly stable…
…laser diode in an external cavity laser (HECL) configuration was detailed by Accuwave Corporation in 19932. Reflection mode VHGs (also called Volume Bragg gratings (VBGs), Bragg mirrors, bulk Bragg gratings, or 3-D Bragg gratings) utilize a photosensitive bulk material in which a periodic change…
…has a physical
dimension of 13×3×14 mm. The thickness of 14 mm results in a narrow reflective bandwidth
of ~ 0.013 nm (~7 GHz). The reflection band is centered at 763.8 nm and the reflectivity is
about 25%. The light-passing surfaces on microlenses and VBG are all AR coated.
…produce different lines, the first step in determining the operating wavelength is to use cavity mirrors that are highly reflective
only at the desired wavelength. The low reflectivity of the mirrors at all the other lines will prevent these from reaching the threshold for laser action.
…uniform distribution of RF energy along the
electrodes (see Figure 2-4).
One of the 100% reflecting end mirrors partially covers the electrode
area. The gap at the end of the mirror forms the output path for the
laser beam. The beam exiting in this gap passes through a zinc
anticipate that the concept can also be applied to arrays and stacks of high power laser diodes.
776 778 780 782 784 786 788
…and spectral bandwidth of the FBG reflectance can be precisely controlled by varying grating parameters. Specifically, these include the grating period, depth of refractive-index modulation, and FBG length. The most obvious use for FBGs is as integrated mirrors or spectrally selective filters. They…
…at 980 nm is split by the first beamsplitter so that part of its intensity is reflected off the OPSL
chip and part is reflected from a super-flat reference mirror. A second beamsplitter recombines
these reflected beams in a configuration called a Mach-Zehnder interferometer. The recombined…
such nontraditional highly aspheric/freeform optics. With traditional optics, you
1220s: Development of glass.
1222: Broad sheet glass was first produced
in Sussex, England.
1500s: Development of mirrors. The method
of making mirrors out of plate glass was
4. Micromirror array
A DLP micromirror array 1264 x 768 from Texas Instruments was obtained from a
commercial projector. The mirror pixel size was not specified but was estimated to be 10 m
x 10 m. The DLP is connected to the board by a flexible cable, which enabled alignment of
…to separate the diffracted
beam and the residual surface reflections, resulting in a clean, ASE-free output.
Wavelength Stabilized Laser Diode ASE Filter
Specular Re ection
ASE Filtered Laser Beam
Transmitted ASE Light
2nd ASE Filter or
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