Miniaturized passive components for coherent modules, DCI platforms and long-haul line systems, with relevant products qualified to Telcordia GR-1221 / GR-1073.
Discuss your line system View coherent componentsCoherent optics are moving from the backbone into more metro and DCI links — and the passive layer has to shrink without giving up performance.
As coherent migration pushes toward 800G and beyond, modules pack more optical functions into less space. Every passive inside must get smaller while holding tighter wavelength and loss budgets.
Metro DCI platforms scale by packing more channels per rack unit. Monitoring, equalization and gain-flattening functions multiply — and each one must fit the module outline, not the other way round.
Over dozens of amplified spans, every fraction of a dB of insertion loss and every trace of PDL eats into OSNR margin. Passives are small parts with an outsized effect on reach.
TALFOD supplies the passive optical layer inside coherent modules and along the line — wherever loss, polarization and size matter.
Inside a coherent ZR/ZR+ module, the mini EDFA (highlighted) sits in the TX output chain and amplifies the modulated signal; the RX path does not pass through this amplifier.
Read the module left to right. On the TX side, the host electrical interface feeds a DSP, then a DAC, a driver and an IQ modulator; after the two polarizations are combined, a mini EDFA boosts the signal before it reaches the TX fiber. On the RX side, light passes a polarization beam splitter and enters the coherent receiver, where it is mixed with the local oscillator from the same tunable laser, and the recovered signal returns through the ADC to the DSP. The red frame marks the passive part of the booster, where we can supply the isolators, IWDMs and photodetectors (PDs).
In some high-power ZR/ZR+ coherent modules, a higher link budget makes an integrated EDFA an important option. At the same time, equipment density in data centers and equipment rooms keeps climbing, so external EDFAs must carry more channels within a limited rack space, moving from single-path amplification to multiple parallel paths. Inside the module and at the equipment-room side alike, miniaturization, higher integration and array packaging are the key directions for passive devices.
Inside coherent modules, we solve the space problem with hybrid integration and folded optical paths. Our IWDM combines isolation and pump coupling in one package, reducing discrete parts and splice points; folded optical paths let light turn back within a small volume and shrink the footprint further. Together with low insertion loss and high-extinction-ratio PM devices, this preserves optical performance within constrained module outlines.
A typical passive chain for an external multi-stage EDFA — tap/PD monitors, isolators, pump WDMs, EDF, GFF, TOF and VOA (dashed frames mark same-package hybrids). TALFOD can supply the passive devices in this chain.
An external EDFA contains a range of passive devices with distinct roles: tap + PD monitors power, isolators suppress back-reflection, WDM couples pump light, GFF flattens gain, TOF suppresses out-of-band ASE, and VOA adjusts output power. Dashed frames mark multiple functions integrated into one hybrid device, allowing one package to replace several discrete components.
In external and multi-stage EDFAs, we combine devices to match the link. IGFF and WIGW handle isolation and gain flattening, Tap PDs monitor power and MEMS VOAs adjust channel power; for parallel amplification, array products such as the 4-in-1 isolator and 2-in-1 IWDM cut device count and board space further. That eases line-card integration and reduces assembly and connection work.
Take ITPD as an example: the early package was Φ5.5×25 mm, and the current ultra-small version is Φ1.4×16 mm — about 75% smaller in diameter, about 36% shorter, and roughly 1/24 of the original volume by outline. Miniaturization is not only about a smaller outline: low insertion loss, high isolation and monitoring accuracy must hold at the same time, which is where our device design and packaging experience show.
We support customers around their module outline, channel count and performance targets, covering device combinations, package matching and custom development. With more than ten years of volume production experience in miniaturized hybrid devices, we respond quickly to selection and customization requests and help customers shorten evaluation and prototyping cycles.
2-in-1 mini IWDM, folded IWDM, isolator+WDM and isolator+GFF hybrids for EDFA and coherent integration — Φ ≤ 3.0 mm ultra-mini packages.
View details →Mini Tap PD, ITPD and Tap+PD hybrids for optical power monitoring inside amplifiers and coherent modules.
View details →MEMS-based variable optical attenuators for per-channel equalization across DWDM lineups.
View details →PM isolators and hybrids, plus PMTC (PM tap coupler) and PBS (polarization beam splitter/combiner) devices for polarization-sensitive coherent optics.
View details →Custom wavelength plans, package outlines and hybrid combinations available. Samples ship worldwide.
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