MIL-C-24621 Revision B, June 6, 1991
COUPLERS, PASSIVE, FIBER OPTIC, GENERAL SPECIFICATION FOR (METRIC)
Includes all amendments and changes through Cancellation Notice 1, February 23, 2000
Additional Comments: CNCL NO S/S
This specification covers the requirements and characteristics of passive fiber optic couplers (see 6.4.7) intended to optically interconnect three or more optical fibers. Directional and bidirectional couplers are covered by this document. Couplers are suitable for interconnection to cable fibers as specified in DOD-C-85045. They are also compatible with splices as specified in MIL-S-24623, and connectors as specified in MIL-C-28876 and MIL-C-83522 (see 6.4.7).
Couplers are classified as specified in 1.2.1 through 1.2.3.
The type designation defines the wavelength of operation of the coupler as well as the method of interfacing the coupler to external fiber optic cables for system applications.
a. Type 1: Nominal center of operation at 1.31 micrometers (µm), with a range of 1.26 to 1.36 µm. Fiber optic cable pigtails are an integral part of the coupler assembly.
b. Type 2: Nominal center of operation at 1.55 µm, with a range of 1.50 µm to 1.60 µm. Fiber optic cable connectors are an integral part of the coupler assembly housing.
c. Type 3: Wavelength independent (range of operation that includes part of all of the wavelength ranges if types 1 and 2).
The class designation defines the optical power distribution made by the coupler. The tolerances of the elements of the transmittance matrix that allow the coupler to be classified as uniformly distributive or nonuniformly distributive (see 6.4.6 and 6.4.10) will be indicated in the specification sheet (see 3.1).
a. Class A: Uniformly distributive (see 6.4.10).
b. Class B: Nonuniformly distributive (see 6.4.6). Beneficial comments (recommendations, additions, deletions) and any pertinent data which may be of use in improving this document should be addressed to: Commander, Naval Sea Systems Command (SEA 55Z3), DOD Standardization Program and Documents Division, Department of the Navy, Washington DC 20362-5101, by using the Standardization Document Improvement Proposal (DD Form 1426) appearing at the end of this document or by letter.
The style designation defines the style of packaging.
a. Style 1: Couplers with single mode fiber pigtails.
b. Style 2: Couplers with multi-mode fiber pigtails.
c. Style 3: Couplers with single mode cable pigtails.
d. Style 4: Couplers with multi-mode cable pigtails.
e. Style 5: Couplers with single mode fiber optic connectors as part of coupler housing.
f. Style 6: Couplers with multimode fiber optic connectors as part of coupler housing.
The term Part or Identifying Number (PIN) is equivalent to the term (part number, identification number, and type designator) which was previously used in this specification. The couplers specified herein (see 3.1) shall be identified by PINs which shall consist of the basic specification number, slash sheet of the specification sheet, and a sequentially assigned number as shown in the following example: