Click here to find helpful information about our technology and products. You can also find FAQs pertaining to VBG setup and use here.
Fiber Optic Packaging FAQs
Other ordering FAQs
Do you offer low power (100 mW) laser diodes in the near infrared (800 – 900 nm) that are frequency stabilized using VBG?
– Currently we offer broad-area single emitters on C-mounts that are 1, 2 or 3 Watts in output power and are wavelength-stabilized. Wavelengths are from around 750 nm to upper 900’s of nm. Single-mode lasers with lower power are also available. Typical packaging options are 9 mm and 5.6 mm TO cans and free-space butterfly package. In either case the lasers are available with circular beam output.
How should I determine the optimum reflectivity of the VBG when I use it for wavelength stabilization?
– We don’t have an exact formula for this. We can tell you that with fast axis collimation only and focal length of that lens ranging from 0.1 mm to 0.9 mm it is sufficient to have a VBG with approximately 30 – 40% intrinsic reflectivity (i.e. measured with light collimated on both axis). When slow axis is collimated as well it may be sufficient to use VBG with 10 – 20% reflectivity. Please note that the result will strongly depend on the characteristics of the laser diode.
Is there a possibility to tune the reflectivity peak by changing the temperature or other parameters? What is the dLambda/dTemp coefficient?
– Yes. The easiest thing is to tune by temperature. The temperature tuning coefficient for our VBG elements is 0.01 nm/K. It is also possible to tune the wavelength in much wider range by rotation. In addition, please note also that we offer gratings with transverse wavelength “chirp” where the Bragg wavelength of the grating varies across its clear aperture. These gratings can be used very efficiently for wavelength tuning.
Is there any angular dependence of the peak wavelength? If yes, please give details.
– The peak wavelength changes with angle as follows: λ = λc*sqrt(1-sinθ^2/n^2), where λc is the cut-off wavelength, θ is the angle of incidence in air and n is the refractive index of glass.
What is the damage threshold and long-time stability for these VGBs (example: laser diode bar with emitter 1 umx10 mm, power 50 W)?
– The gratings have been tested with ~ 50 MW/cm2 cw power density at 1064 nm without any damage. They have also been shown to survive when operating at ~ 200 MW/cm2 with Q-switched (ns pulse duration) lasers.
What is the optimum reflectivity when used for the above purpose (stabilizing the wavelength of laser diodes used in pumping solid-state lasers)?
– It depends on the front facet coating, the design of the laser chip as well as the collimation optics.
What is the typical thickness of the VGB itself in the glass wafer in order to achieve the near 100% reflectivity?
– The Bragg grating penetrates the entire volume of glass. So the entire 1 mm of glass thickness is the Bragg grating. In 1 mm of glass we have achieved approximately 93% reflectivity at around 800 nm. We recommend gratings with thickness of > 4 mm in order to achieve reflectivity of > 99.5%.
What is the useful range of wavelengths?
– In general, it is anywhere between 350 and 3000 nm, depending on how much loss you are willing to tolerate. As part of the research, we have actually made recordings at wavelengths from 480 nm to the 1550 nm range. Our wavelength locking products, however, are offered in the 630 to 1064 nm range. There are some standard wavelengths in that range that are offered with faster delivery times and at lower prices then others: 785 nm, 808 nm, nm and 976 nm.
How can I pay for my order?
– PD-LD, Inc, accepts all major credit cards. In addition we accept prepayment for orders. If you would like to apply for terms with PD-LD, Inc and your order is above $1000.00 please contact us at 609-564-7900.
How do I place an order?
– To place your order, you may fill in our contact form, fax your request to the attention of Sales at 609-564-7901, email us at info@PD-LD.com or phone us at 609-564-7900. Please include your Billing/Shipping address, PO number, and method of shipment, part number and quantity you would like to order.
do I receive a quote for a product I am interested in?
– In order to receive a quote you may either fill in our contact form, fax your request to the attention of Sales at 609-564-7901, email us at info@PD-LD.com or phone us at 609-564-7900. Please include the part number and quantity required.