Secure communication provided by cryptography is of vital importance in many activities of the information society. The security of traditional public-key cryptosystems is based on computational complexity and can be broken by powerful computers. Fortunately, with the advent of Quantum cryptography unconditionally secure encryption can be guaranteed by the laws of (quantum) physics. Quantum cryptography allows for the parties to securely obtain secret keys by using Quantum Key Distribution (QKD). The two most popular forms of QKD are Discrete Variable QKD (DV-QKD) and Continuous Variable QKD (CV-QKD). DV-QKD distributes the secret key by encoding information in single photons while CV-QKD makes use of continuous properties attributed to streams of photons. DV-QKD receivers require single photon detectors which are limited in bandwidth and spectral selectivity while also being relatively expensive. The advantage of the CV-QKD approach is that single photon detectors are no longer required. Instead, less expensive and faster telecom components can be adopted. Up to now CV-QKD systems have mostly been limited to bench-top experiments, using discrete photonic and electronic systems. These experiments are valuable from a scientific point of view but are impractical and costly for commercial applications. This project aims to realize the shift from basic science to engineering by developing and implementing an integrated balanced receiver with a high sensitivity and bandwidth.