Innolume Gain chip – gain chip / RSOA for tunable lasers

A gain chip (gain element, also referred to as a reflective SOA / RSOA) is a key component of tunable lasers and stable external cavity lasers (ECL – external cavity laser). Innolume gain chips, based on quantum-dot and quantum-well technology, cover the 765–1360 nm range. Thanks to deep anti-reflection (deep AR) coatings on one or both facets, they provide wide, hopping-free tuning without the self-lasing effect.

Unlike standard laser diode chips, a gain chip has a deep anti-reflection coating that significantly raises the self-lasing threshold or eliminates it entirely. This makes it an ideal gain medium in diffraction-grating configurations (Littrow, Littman/Metcalf), where the wavelength is tuned by rotating the grating. Gain chips are used in external cavity lasers, swept sources and broadband sources – including in OCT tomography, spectroscopy and LiDAR systems.

Optimized for external cavity operation – design dedicated to ECL lasers with wavelength locking.
Wide tuning range without mode hopping (hopping-free).
High side-mode suppression ratio (SMSR).
No self-lasing at maximum current.
Deep anti-reflection (deep AR) coatings – reflectance even below 10⁻⁵.
Fiber-coupled (gain-module) versions – fiber output for easy system integration, low beam ellipticity and simple optical assembly.

Type A – straight stripes and deep AR coatings; an economical solution for external cavities, symmetric far-field distribution.
Type B – curved stripe and deep AR coating; ultra-low reflectance (<10⁻⁵), self-lasing suppression and gain ripple minimization.
Type C – curved stripes with low reflectance on one facet and partial reflection on the other; balances output power and beam quality (basis for fiber-coupled modules).
Type D – deep AR coatings on both sides; supports advanced optical schemes with integrated amplification.

• External cavity lasers (ECL) – Littrow and Littman/Metcalf
• Tunable lasers and swept sources
• OCT optical tomography and biomedical imaging
• Spectroscopy and high-precision scientific research
• LiDAR systems (high-speed scanning, precise mapping)
• Broadband sources

Innolume gain chips are supplied as individually configured solutions – wavelength, facet reflectance and other parameters can be selected for a specific application. Contact us to choose the optimal configuration and to receive the datasheet of the selected model and a quote.