Skip to product information
BP1535-20 Bandpass Filter(CWL=1535nm,FWHM=20nm)
  • BP1535-20 Bandpass Filter(CWL=1535nm,FWHM=20nm)
  • Black bandpass filter with technical specifications on a white background
BP1535-20 Bandpass Filter(CWL=1535nm,FWHM=20nm)

BP1535-20 Bandpass Filter(CWL=1535nm,FWHM=20nm)

SO3010044

Center Wavelength (CWL) // FWHM
Center Wavelength (CWL) // FWHM
CWL=1535nm // FWHM=20nm
Optical Density // Peak Transmission (Tpk)
Optical Density // Peak Transmission (Tpk)
OD3@600-2000nm // T＞90%
SO3010044-d12.5u
In stock
$115.00
$115.00
  • American Express
  • Apple Pay
  • Discover
  • Google Pay
  • JCB
  • Mastercard
  • Visa
Stock Availability

Yes. Listed filters are generally available from stock, but final availability may depend on size and quantity.

  • Most filters are kept as medium-sized coated pieces
  • Final size is usually diced before shipment
  • Preparation time may vary for urgent orders, custom sizes, or larger quantities
Custom Size & Mounting

We can usually cut optical filters to custom outer sizes, depending on available coated material.

Custom size
  • Typical custom size range: 3 × 3mm to 60 × 60mm
  • Custom sizing changes the outer dimension only
  • Thickness normally follows the original filter specification
  • Final feasibility depends on coated material size and cutting requirements
Mounting
  • Standard mounting options are
    dia12.5mm (mounted) - OD = dia12.5mm,Thickness=3.5mm,No Thread
    dia25mm (mounted) - OD = dia25mm,Thickness=3.5mm,No Thread
  • Mounted options can include non-threaded or threaded mounts
  • Custom mounting may be possible depending on quantity and mechanical requirements
Note
  • Please send the required size, quantity, mounting type, and product link before ordering.
Request Raw Data

Yes. You may request the transmission curve or related spectral data for engineering review.

Copy the link of the product page and send email to shop@syronoptics.com, you will get reply within 1 working days.
Shipment & Delivery

We ship optical products to most supported regions, with shipping cost and delivery method confirmed before payment.

Shipping cost
  • Shipping is generally USD 5–40 per parcel
  • Orders above USD 300 are eligible for free shipping
  • Final cost depends on destination, package size, order value, and shipping method
  • Shipping cost is shown during checkout or confirmed before payment
Shipping coverage
  • We generally ship to Europe, North America, Asia, the Middle East, and Oceania
  • Some countries may be unavailable depending on logistics or customs conditions
Delivery time
  • Most stocked products need 1–5 working days for preparation before shipment
  • After shipment, delivery time depends on destination and shipping method
  • Tracking information will be provided when available
Note
  • If your destination is not available during checkout, please contact us before ordering.
Payment & Quotation

You can order online, request a quotation, or use bank transfer depending on your purchasing process.

Can I request a quotation before ordering?
  • Yes, formal quotations are available before payment
  • Recommended for company purchases, larger quantities, custom sizes, or special shipping requirements
  • Please send the product link, quantity, destination country, and billing details if available
What online payment methods are available?
  • Credit card
  • Apple Pay
  • Google Pay
Do you support bank transfer?
  • Yes, bank transfer is available
  • We support multi-currency payment through local banking where available
  • Local receiving accounts may include US, UK, Germany, Singapore, and Hong Kong bank accounts
  • For payment in Chinese RMB inside Mainland China, please contact our local partner
  • VAT fapiao may be supported for eligible Mainland China transactions
Do you support company purchase orders?
  • Company purchase orders may be supported after confirmation
  • Please contact us before ordering if your organization requires PO processing, quotation, or invoice matching
Are NET payment terms available? (Pay after received)
  • NET 7 or NET 30 terms may be available for eligible organizations
  • Approval depends on company type, order value, payment history, and internal review
  • Please contact us before ordering if you need NET payment terms
Import, Duties & Customs

mport duties, taxes, and customs handling depend on your destination country and shipping method.

Are duties and taxes included?
  • For express courier services such as DHL or FedEx, duties, taxes, and customs handling are usually paid by the buyer
  • The final import cost depends on destination country, declared value, and local customs rules
  • Duties and taxes are not included unless clearly confirmed before payment
Can SyronOptics help with import clearance?
  • Import-handled delivery may be available for selected regions
  • Supported regions may include USA, Canada, United Kingdom,Europe, Mainland China, Hong Kong, Singapore, Australia, and New Zealand
  • With import-handled delivery, we help arrange clearance and local delivery
  • This option may be slower than express courier
Note
  • If you are not sure, please contact us to confirm whether import-handled delivery is supported in your region.
  • Wavelength: Center wavelength 1535nm with 20nm FWHM bandwidth for short-wave infrared spectrum transmission
  • Spectral Features: Narrow bandwidth with steep edge transitions for precise SWIR spectral isolation
  • Optical Density: OD3+ blocking outside passband for strong background suppression
  • Filter Dimension Availability: Available in standard round and square formats to fit common optical mounts

Spectral Data & AOI Review

Filter curves can shift when the filter is used at an angle.

SyronOptics can review spectral data and selected AOI examples to help check whether a filter fits the actual optical path.

LIDT Reference (1064nm)

Selected 1064nm laser damage test data is available for reference when reviewing similar laser-related filter designs.

Final suitability depends on the actual laser condition, coating design, beam size, and system setup.

Custom Size Cutting

Coated filter plates can often be cut into smaller formats for custom optical assemblies.

For narrow bandpass filters, usable area and size may depend on coating uniformity across the larger piece.

BP1535-20 Bandpass Filter - SWIR Imaging & Active Night Vision

BP1535-20 Bandpass Filter - SWIR Imaging & Active Night Vision

SWIR Imaging & Active Night Vision

  • Used in SWIR cameras to detect active illumination (laser designators or beacons) while rejecting ambient light.

Recommended Light Sources

  • Er:Glass Laser

Wavelength Match: These solid-state lasers naturally emit at exactly 1535 nm, which aligns perfectly with the center wavelength of your BP1535-20 filter. This ensures maximum signal transmission through the filter while ambient light is blocked.

  • 1535 nm Laser Diode

Application: For smaller, portable "beacons" (worn on helmets or vehicles) that do not require the extreme range of a designator, a semiconductor laser diode tuned to 1535 nm is often used.

BP1535-20 Bandpass Filter - Eye-Safe Laser Rangefinding

BP1535-20 Bandpass Filter - Eye-Safe Laser Rangefinding

Eye-Safe Laser Rangefinding

  • The 1535 nm wavelength is the industry standard for eye-safe laser rangefinders (LRF) and LIDAR systems used in military and outdoor commercial applications. Unlike 1064 nm lasers, 1535 nm is absorbed by the fluid in the eye before reaching the retina, making it much safer for human vision at higher power levels.
  • The filter is used in the receiver to block sunlight and other background noise, allowing the sensor to detect the weak reflected laser pulse.

Recommended Light Sources

  • Er:Glass Solid-State Laser
  1. Wavelength Precision: These lasers rely on an Erbium-doped phosphate glass gain medium, which naturally emits light at 1535 nm. This perfectly matches the center wavelength of your BP1535-20 filter, ensuring the receiver captures the maximum amount of signal.
  2. High Peak Power (Q-Switching): Er:Glass lasers are typically "Q-switched" (often using a passive Co:Spinel crystal). This allows them to store energy and release it in incredibly short, high-intensity pulses (lasting just a few nanoseconds). This high peak power is essential for the "Time-of-Flight" calculations used to measure long distances accurately.

Similar 1535nm Bandpass Filters

Product FAQs

What is the difference between unmounted, mounted, and threaded filter options?

For size options, unmounted and mounted filters use different size references.

Unmounted filters
  • Listed size refers to the actual filter size
  • Example: 12.5mm unmounted means the bare filter is 12.5mm in diameter
Mounted filters
  • Listed size usually refers to the outside size of the mount
  • The filter inside is typically smaller than the mount
  • Example: 12.5mm mounted means the mount outside is 12.5mm, while the filter inside is slightly smaller
  • The inside filter is usually about 1–1.5mm smaller than the mounted outer diameter
Mount type
  • Mounted does not automatically mean threaded
  • If only labeled as mounted, it usually means a smooth, non-threaded mount
  • Threaded mounts should specify a thread standard, such as M25.5 × 0.5mm or SM1
Note
  • If your system has strict requirements for outer diameter, clear aperture, thickness, or thread standard, please confirm before ordering.

How thick is the optical filter?

Filter thickness depends on whether the filter is supplied unmounted or mounted.

Unmounted filters
  • Usually 0.5mm–2mm
  • Common thicknesses: 0.5mm, 1.1mm, 1.5mm
  • Other cases may range from about 0.3mm–3mm
  • Thickness may vary by substrate, coating design, or customer requirement
Mounted filters
  • Total outside thickness depends on the mount structure
  • Non-threaded mount: usually around 3.5mm or 6mm
  • Metric threaded mount: usually around 6.5mm–7.5mm
Note
  • If your system has a strict thickness limit, please confirm the required thickness before ordering.

How is the filter fixed inside the mount?

The fixing method depends on whether the mount is threaded or non-threaded.

Non-threaded mounts
  • Filter is usually fixed with adhesive
  • The filter is secured inside the mount after assembly
  • The filter is generally not removable after mounting
Threaded mounts
  • Filter is usually held with a retaining ring
  • Adhesive is usually not required
  • The filter can usually be removed or replaced later
Note
  • If you need the filter to be removable, please request a threaded mount with retaining ring before ordering.

Can this filter be used at a non-normal angle of incidence?

Yes, but the spectrum may shift when the filter is used away from normal incidence.

Narrow bandpass filters
  • Around 10nm FWHM: small angles such as 0–5° usually have limited effect
  • At 10–15°, wavelength shift may become noticeable
  • Tight spectral systems should check AOI carefully before ordering
Wide bandpass filters
  • Around 50–100nm FWHM: usually more tolerant of angle shift
  • Around 15–20° may still be acceptable in some systems
  • Final suitability depends on the required passband and blocking range
Note
  • Non-normal incidence may also introduce polarization-related effects
  • If your system uses larger AOI, polarized light, or tight wavelength tolerance, please confirm before ordering.

Can you test the filter at different angles of incidence?

Yes. We can provide AOI (angle-of-incidence) testing at selected angles.

AOI testing options
  • Common test angles: 5°, 10°, 15°, 20°, 30°
  • Used to review wavelength shift under non-normal incidence
  • Suitable for laser, imaging, or angle-sensitive optical systems
Cost
  • USD 35 per angle
  • Minimum: 2 angles per request
Note
  • AOI testing can be requested before placing an order
  • This allows you to review measured performance before confirming system compatibility

What if I am not sure which filter fits my system?

If you are not sure, testing a sample in your own system is often the best way to confirm fit.

Sample testing
  • Available for eligible company, laboratory, university, or research-group customers
  • Usually applies to products or orders below USD 150
  • You may test first and pay only if the filter works for your system
Return after testing
  • If the filter is not suitable, you may return it after testing
  • Return approval depends on product condition and review
  • Custom, modified, damaged, or contaminated products may not be eligible
Note
  • Please contact us before ordering if you want to check whether sample testing is available.

Need Help Confirming This Filter?

Whether you are replacing an existing part or building a new system, send us:

- Original part number or target specification
- Required size and quantity
- Application or system goal

We will help check product fit or suggest a stock/custom alternative.