Parameter

Coating curve

Both single-mode and multimode fibers can be coated, although the angular distribution in multimode fiber must take into account the AOI distribution at the coating. Coatings can be designed to operate when coupled to another fiber or to air. We can offer a wide range of filter designs such as anti-reflection, bandpass, short-pass, long-pass, and partial reflectors.

Coated shorts can be connectorized, bare, tapered, or lensed fibers.

Filter film characteristics ¹

● (circle one) LP SP BP Reflector (full or partial)

● Start wavelength ____ ±____

● Cut-off wavelength ____ ±____

● %T (peak)

● Attenuation wavelength range

● Attenuation OD

● %R (peak) ±

● %R wavelength range

Fiber characteristics ²

● Numerical aperture (NA)

● Core diameter

● Cladding diameter

● Fiber length

● Fiber material (glass, plastic, chalcogenide) Single mode or multimode at operating wavelength (circular)

● Mode filling degree (if known)_______

● Maximum operating temperature of the casing_______

● Others (polarization-maintaining fiber, microstructure fiber, etc.)

Fiber end face features³

● First end connector (FC, SC, LC, SMA, None)

● Second end connector (FC, SC, LC, SMA, None)

● If no connector (cleaved, lensed, bare fiber)

● Which end needs coating

Fiber Configuration⁴

● Coated tip working in air

● Coated tip connected to uncoated tip

● Number of coatings required

● Fiber supplier

E.g.: BP-0760-037 Specifications:

CWL: 760 ±7 nm HW: 37 ±7 nm

Tmin: 60 %

Blocking: 1200 nm

Measured values:

CWL = 759.88 nm...OK 

HW = 38.5 nm...OK

Cuton 5 % = 732.43 nm 

Cutoff 5 % = 788.55 nm

Spectrogon:

HP1 = 740.63 nm

HP2 = 779.12 nm

Tpeak = 93.14 %...OK 

Tavg = 90.46 %

Slope 1 = 1.55 % 

Slope 2 = 1.7 %

Notes:

1. The steep spectral edges and tight blocking specifications lead to designs with high physical thickness. We have found that the tip of the fiber can support up to 6 microns of material. Thick coatings may delaminate and/or cause core-cladding leakage. Customers are advised to use the recommended filter thickness.

2. High NA multimode fibers lead to high AOI. High AOI causes any interference filter to blue shift. The observed spectral performance will be a weighted average of the performance at each angle. These spectral shifts can be modeled and measured in the AOI lab.

3.Idealphotonics monitors the reflectivity of the fiber tip during the deposition process. This requires that the uncoated end of the monitoring fiber must be terminated with a connector (preferably FC/PC). If the connected end is not suitable for a given application, we will place an additional fiber near the customer's fiber for monitoring.

4. If a single-mode tip is coated and connected to another single-mode tip, a near-zero blue shift will occur. The number of fiber lengths allowed for one deposition depends on the fiber configuration (connected, cleaved, bundled, etc.).