Resonance Free Conical Inductor Precision Metal Inductor Low Jitter

Custom Conical Inductor Resonance Free Dynamic Bandwidth Gradient Pitch Taper Ratio Ultra Low Jitter Optical

HACC-CUSTOM-BW: Resonance-Free Conical Inductor with Gradient Variable Pitch & Ultra-Low Jitter for High-Speed Optical Modules

Resonance-Free Dynamic Bandwidth Customization

Standard conical inductors with uniform winding pitch exhibit parasitic series resonances — impedance nulls where the inductor behaves as a capacitor — limiting usable bandwidth. The HACC-CUSTOM-BW eliminates these nulls through a custom non-uniform pitch profile: winding pitch is varied progressively from the apex (tight) to the base (wider), creating a continuous impedance transition that suppresses the standing wave reflections responsible for resonance nulls. The result is a flat impedance response with variation below ±10% across the full specified band from 100 MHz to 40 GHz, with no nulls deeper than -3 dB return loss. The pitch profile P(z) is customer-specified: linear, exponential, or stepped — each optimized for a specific band shape. Every device is verified with a VNA sweep from 10 MHz to 50 GHz, and a Touchstone .s2p file confirms resonance-free operation before shipment.

Engineered Gradient/Variable Pitch & Taper Ratios

Beyond pitch variation, the HACC-CUSTOM-BW offers full control over the conical taper geometry. The taper ratio — the diameter gradient from the small apex to the wide base — is customer-specified within an angle range of 2° to 15°. Apex diameter is selectable from 0.2 mm to 0.8 mm, base diameter from 0.8 mm to 3.0 mm, and overall coil length from 1.5 mm to 5.0 mm. The wire diameter gradient along the coil (0.025 mm to 0.08 mm options) adds a second degree of freedom: combining variable pitch with variable taper and stepped wire gauge enables simultaneous optimization of low-frequency inductance (larger base turns, wider pitch) and high-frequency SRF (smaller apex turns, tighter pitch). This multi-parameter taper engineering is unique to custom HACC conical inductors and is not possible with off-the-shelf fixed-geometry components.

Ultra-Low Jitter Optimization for High-Speed Optical Modules

In 56G and 100G PAM4 optical transceivers, the bias tee inductor is a critical source of deterministic jitter. Any impedance nonlinearity or parasitic resonance in the bias path converts AM noise to PM noise, degrading the PAM4 eye diagram. The HACC-CUSTOM-BW is specifically designed for this application: RMS jitter contribution is below 100 fs in a standard 100G Lambda MSA test setup, and phase noise is maintained below -160 dBc/Hz at 10 kHz offset. The resonance-free bandwidth profile ensures consistent bias injection impedance across the full data spectrum from 100 MHz to 40 GHz — eliminating the bias-tee-induced eye closure common with generic conical inductors. Compatible with 100G Lambda MSA, 400G-FR4, and CPO (co-packaged optics) reference designs.

Key Specifications

Applications

• 100G Lambda MSA / 400G-FR4 Optical Transceivers — <100 fs RMS jitter bias tee, resonance-free 100 MHz–40 GHz for clean PAM4 eye
• Co-Packaged Optics (CPO) — Custom taper geometry for compact module integration, flat Z(f) for multi-channel bias injection
• Broadband Bias Tees (Test & Measurement) — Resonance-free 100 MHz–40 GHz, <0.5 dB insertion loss, .s2p verified per device
• Microwave Photonics — Phase noise <-160 dBc/Hz, minimal AM-to-PM conversion for low-noise laser bias

Contact us with your target inductance, frequency band, and taper geometry requirements. Resonance-free conical inductors with custom pitch profiles ship in 5–7 business days.