Ascentta High Directivity Ultra-broadband 3-port Optical Circulator

The Ascentta ultra‑broadband single‑mode 3‑port optical circulator is a non‑reciprocal, three‑port passive device that routes light sequentially from Port 1→2 and Port 2→3 while isolating the reverse directions. It is designed for single‑mode operation over an ultra‑wide wavelength range of 1290–1620 nm, covering O-, E-, S-, C- and L‑bands. Typical applications include fiber‑optic communications, bidirectional transmission, test and measurement setups, and optical sensing, where wideband performance and stable isolation over a large spectrum are required.

This 3‑port optical circulator is designed so that light entering Port 1 is transmitted to Port 2, and light entering Port 2 is transmitted to Port 3. Reverse propagation is strongly suppressed: light from Port 2 back to Port 1 and from Port 3 back to Port 2 experiences high isolation. At the center wavelength and 23 °C, the typical isolation is 23 dB and the minimum specified isolation is 20 dB for all states of polarization. In addition, the device provides a minimum directivity of 50 dB between non‑adjacent ports (1→3 or 3→1), which helps prevent unwanted back‑reflections and crosstalk in complex fiber networks.

For all states of polarization and at 23 °C, the typical insertion loss from Port 1→2 or Port 2→3 is 1.7 dB, with a maximum specified insertion loss of 2.0 dB. The polarization‑dependent loss (PDL) is ≤ 0.25 dB, ensuring stable performance with varying input polarization, which is important in real‑world fiber links. The polarization mode dispersion (PMD) is ≤ 0.2 ps, making the device well‑suited for high‑bit‑rate systems where dispersion must be minimized. The minimum return loss is 50 dB, which significantly reduces back‑reflection into upstream components such as lasers, EDFAs, or transceivers.

This ultra‑broadband 3‑port optical circulator supports a maximum continuous optical power handling of 300 mW, which covers most telecom and test & measurement applications and many lab setups. The specified operating temperature range is −5 °C to +70 °C, allowing deployment in controlled indoor and light industrial environments. For long‑term storage and shipping, the approved storage temperature range is −40 °C to +85 °C. These environmental specifications are comparable to many high‑quality telecom‑grade circulators available on the market.

The standard fiber type options are SMF‑28 single‑mode fiber in 250 µm bare fiber (code B) or 900 µm tight buffer (code L); other fiber types can be requested (code X). Standard fiber lengths include 1.0 m (10), 1.5 m (15), 2.0 m (20), and 3.0 m (30), with custom lengths available on request. Connector options include none (NE), FC/APC (FA), FC/PC (FC), SC/APC (SA), SC/PC (SC), ST/PC (ST), LC/APC (LA) and LC/PC (LC), as well as custom connectors (X). The standard package is a cylindrical housing with a diameter of 5.5 mm and length of 50 mm, and a mini package 5.5 × 38 mm is also offered. Note that adding connectors slightly increases insertion loss and may affect return loss and PDL relative to bare‑fiber performance.

An ultra‑broadband 3‑port optical circulator covering 1290–1620 nm is ideal for systems that need wide spectral coverage or multi‑band operation. Common applications include bidirectional fiber‑optic communication links (e.g., combining upstream and downstream traffic on a single fiber), OTDR and other test and measurement setups, interferometric and fiber Bragg grating (FBG) sensing, distributed temperature/strain sensing, and optical add‑drop or reflection‑based devices. Compared with narrowband circulators specified only for C‑ or C+L‑band, this device allows experimentation or deployment across O‑, E‑, S‑, C‑ and L‑bands with consistent isolation and low PDL.

Ascentta uses an ordering code that defines the port count, wavelength range, fiber type, fiber length, connectors, and package style. For this device, you would start with CIR (circulator family) and 3 for a 3‑port unit, then choose the wavelength code 1290‑1620 for the 1290–1620 nm range. Next select the fiber type (B for SMF‑28, 250 µm; L for SMF‑28, 900 µm; or X for other fibers), followed by the desired fiber length code (10, 15, 20, 30, or X for custom). Then choose connector types such as NE, FC/PC, FC/APC, SC/PC, SC/APC, ST/PC, LC/PC, LC/APC, or X for others, and finally select the package: blank for the standard 5.5 × 50 mm housing, 5.5×38 for the mini package, or X for a custom package. For assistance with non‑standard wavelengths, higher power handling, or unique mechanical or environmental requirements, Ascentta recommends contacting their sales/engineering team directly.