Polarization Maintaining Photonic Integration PM Isolator WDM Hybrid Device 1550nm 1480nm 980nm

  The PM Isolator + WDM Hybrid Device (PM IWDM for short) is a hybrid device that integrates polarization-maintaining isolator and wavelength division multiplexing (WDM) functionality into a single device. It is used to simultaneously perform multiplexing/demultiplexing and unidirectional isolation of signal and pump light within a single optical fiber. The product supports multiple wavelength combinations, such as 1550/1480, 1550/1310, 1480/1550, and 1550/980 nm, covering typical C-band signals and 1310 nm/1480 nm/980 nm pump configuration requirements. The device offers both single-stage and dual-stage isolation configurations, with signal channel insertion loss as low as ≤0.9 dB (single-stage) / ≤1.0 dB (dual-stage) and pump channel insertion loss as low as ≤0.5 dB (single-stage) / ≤0.8 dB (dual-stage), and features an extinction ratio of ≥21 dB and a directivity of ≥55 dB. The pigtail can be made of SMF-28e or PM1550/PM980 polarization-maintaining fiber, packaged in a φ5.5 * 38 mm steel tube, suitable for integration into compact amplification modules and instruments.

  At the system application level, the PM IWDM is primarily targeted at applications such as fiber amplifiers (EDFA/Raman), polarization-maintaining fiber lasers, and high-end fiber optic instruments. For C-band EDFAs, it can simultaneously combine 1550 nm signals and 1480/980 nm pump light, providing unidirectional isolation for the signal channel, thereby reducing the number of components and fusion splices, and simplifying the amplification module structure. In polarization-maintaining fiber laser systems, the seed source signal light and pump source can be injected into the active fiber via IWDM, and the isolation function can suppress external reflections and backscattering, improving laser stability. In fiber optic test and measurement equipment, it can be used to construct an integrated "source + amplification + isolation + combining" optical path, making the whole system more compact and reducing uncertainties caused by free space or multi-component cascading.

  In terms of performance characteristics, PM IWDMs offer advantages such as a wide operating wavelength range, low loss, high isolation, high extinction ratio, and high power handling capability. The signal channel operates in the 1528–1565 nm C-band, with corresponding pump wavelengths of 1450–1490 nm, 1270–1350 nm, or 965–995 nm, adaptable to various amplification and laser solutions. The signal channel insertion loss is ≤0.9 dB for a single stage and ≤1.0 dB for two stages, while the pump channel insertion loss is ≤0.5 dB for a single stage and ≤0.8 dB for two stages, helping to maintain system power budget. In terms of isolation, a single-stage structure can achieve ≥21 dB isolation, and a two-stage structure can achieve ≥36 dB. Pump transmission isolation is ≥30 dB, and signal reflection isolation is ≥15 dB, effectively suppressing backlight and crosstalk. The extinction ratio is ≥21 dB, the directivity is ≥55 dB, and the maximum optical power handling capability is ≤1000 mW, supporting medium-to-high power applications. The device operates within a temperature range of 0 to +70 °C and has a storage temperature range of -5 to +75 °C, exhibiting excellent stability and reliability under long-term operation and environmental changes.

  From a system integration and optical path design perspective, PM IWDMs are ideally suited for use as core node devices with multi-functional capabilities. In a typical amplification module, it can be placed at the front end of an active fiber: the Common end receives signal light from the main system link, the Pump end receives 980/1480 nm pump light, and the Pass end outputs a multiplexed signal with isolation protection, achieving integrated "isolation + multiplexing" functionality. In a reverse-pump structure, a Backward pump configuration can be used to inject pump light from the opposite direction while controlling the signal direction. In multi-stage amplification or multi-segment active fiber structures, multiple IWDMs can be cascaded to flexibly inject pump sources from different stages into different locations, and the isolation segments effectively isolate reflections and noise between amplification stages. For modular devices and instruments requiring a compact structure, engineers can achieve "plug-and-play" optical path integration by selecting the pigtail type (SMF or PM), length, and sheath.

  Compared to the traditional "standalone WDM + standalone isolator" solution, PM IWDM offers significant advantages in structural simplification, loss control, polarization maintenance, and system reliability. First, hybrid integration combines two key functions within the same package, significantly reducing fusion splices and connection points, lowering assembly complexity and cumulative insertion loss, while also reducing module size. Second, in polarization-maintaining configurations, the signal channel uses PM1550 polarization-maintaining fiber, while the pump and common port can use PM980 or other polarization-maintaining fibers, ensuring the entire system maintains polarization consistency and predictability while performing multiplexing and isolation, making it ideal for polarization-sensitive amplification and laser systems. Third, standardized device parameter specifications (such as isolation, insertion loss, extinction ratio, and power handling) facilitate modeling in link budgeting and simulation for engineers. Through flexible ordering codes, users can customize the device by signal/pump wavelength combinations (e.g., 1550/1480, 1550/1310, 1550/980), single/dual stage, forward/backward pumping, packaging method, pigtail type and length, connector type, etc., enabling the same platform to adapt to various product and project requirements.

  Overall, the PM Isolator + WDM Hybrid Device (PM IWDM) is a key integrated passive device for fiber amplifiers, polarization-maintaining fiber lasers, and high-end fiber optic instruments. By integrating wavelength division multiplexing and optical isolation into a single package, it achieves a compact, balanced, and highly reliable optical path solution. It excels in wide operating wavelength, low insertion loss, high isolation, high extinction ratio, and high power handling capability, while also ensuring polarization maintenance and ease of engineering integration. For equipment manufacturers and system integrators who want to achieve high-performance amplification and pump management within limited space and a limited number of devices, the appropriate selection and deployment of PM IWDM can not only improve the system's OSNR and long-term stability, but also reduce assembly difficulty and maintenance costs, providing a solid device foundation for the next generation of highly integrated photonic systems.