Ascentta Single Mode Polarization Insensitive Optical Circulator (635nm or 532nm, 780nm, 850nm)

A 3‑port TGG type optical circulator is a non‑reciprocal, passive fiber‑optic component that routes light directionally from port 1→2 and 2→3 while strongly isolating back‑reflected light. “TGG type” refers to the Terbium Gallium Garnet crystal used as the Faraday rotator inside the device. When light enters port 1, it exits port 2; light entering port 2 exits port 3. Light that tries to travel in the reverse direction (2→1 or 3→2) is highly attenuated (isolated). This behavior is used in single‑mode fiber laser systems, optical sensing, and test setups to separate forward‑propagating signals from back‑reflections and to protect laser sources.

This Ascentta 3‑port circulator is designed for single‑mode operation at discrete visible and near‑IR wavelengths. Standard wavelengths include 532 nm, 635 nm, 650 nm, 780 nm, 850 nm, 980 nm, 1030 nm, and 1060 nm. The standard fiber type is single‑mode (code “S” in the ordering information). Other wavelengths or fiber options can be requested as custom configurations (code “X=Others”). Compared to many generic telecom circulators optimized only for 1310/1550 nm, this device specifically targets visible and Yb‑fiber‑laser bands commonly used in bio‑photonics, metrology, and industrial laser systems.

For all supported wavelengths, the device provides: - **Transmitting direction:** 1→2 and 2→3 - **Isolation (reverse, 2→1 or 3→2):** Typical 23–27 dB depending on wavelength; minimum 20–22 dB - 532/635/650 nm: typ. 23 dB (min. 20 dB) - 780/850 nm: typ. 25 dB (min. 21 dB) - 980/1030/1060 nm: typ. 27 dB (min. 22 dB) - **Insertion Loss (1→2 or 2→3):** - 532 nm: ≤2.5 dB - 635/650 nm: ≤2.3 dB - 780/850 nm: ≤1.8 dB - 980/1030/1060 nm: ≤1.5 dB - **Return Loss:** ≥45 dB - **Directivity (1→3 or 3→1):** ≥40 dB - **Polarization Dependent Loss (PDL):** ≤0.2 dB - **Polarization Mode Dispersion (PMD):** ≤0.2 ps These values are competitive with similar 3‑port single‑mode circulators on the market. Note that adding connectors can slightly degrade insertion loss, return loss, and PDL.

The maximum continuous optical power handling depends on the wavelength: - 532 nm: up to 50 mW - 635 nm and 650 nm: up to 100 mW - 780 nm and 850 nm: up to 150 mW - 980 nm, 1030 nm, 1060 nm: up to 250 mW The datasheet notes that **maximum power affects other specifications** (e.g., isolation and insertion loss can shift at higher powers), which is consistent with many TGG‑based circulators. If your application requires higher power, shorter pulses, or unusual duty cycles, you should contact Ascentta for a custom high‑power version and confirm safe operating limits.

Standard cylindrical package dimensions depend on wavelength: - 532 nm: Φ21 × L60 mm - 635/650 nm: Φ21 × L75 mm - 780/850 nm: Φ24 × L80 mm - 980/1030/1060 nm: Φ24 × L95 mm Cable type and length options: - Cable diameter: B=250 µm bare fiber, L=900 µm loose tube, H=3 mm jacket (others as “X”) - Fiber length: 1.0 m (10), 1.5 m (15), 2.0 m (20), 3.0 m (30), or custom (“X=Others”) Standard connector options on each port include: NE=None, FC/PC, FC/APC, SC/PC, SC/APC, ST/PC, LC/PC, LC/APC (or “X=Others” for custom). As is typical for fiber circulators, using connectors slightly increases insertion loss and may reduce return loss; for the best performance many lab setups use pigtails without connectors.

The specified environmental ranges are: - **Operating temperature:** +10 °C to +50 °C - **Storage temperature:** 0 °C to +60 °C This is slightly narrower than some telecom‑grade circulators (often −5/−20 °C to +70 °C), reflecting that this unit targets lab, industrial, and OEM environments where room‑temperature or mildly controlled conditions are typical. Within the specified operating range, the isolation and insertion loss specs apply for all states of polarization (SOP). For applications in harsher or outdoor environments, you should discuss extended‑temperature versions or additional thermal control with Ascentta.

The part number is built from several fields as shown in the ordering information. A typical code looks like: VCIR – [Port] [Wavelength] [Fiber Type] [Cable Type] [Fiber Length] [Connector] [Max Power] [Package] For example: **VCIR3–980–S–H–20–FA–X–X** could represent a 3‑port single‑mode circulator at 980 nm, with 3 mm jacketed fiber, 2.0 m pigtails, FC/APC connectors, standard power rating and standard package. Use “X” in any field to request a non‑standard option (other wavelength, fiber, power rating, or mechanical package). Because maximum power and connectors can influence optical performance, it is recommended to share your detailed application (wavelength, power level, environment, fiber/connector preferences) with Ascentta’s sales or engineering team when requesting a quote.